Fermented Sausages: Control Design and Equipment Construction
Includes Chuckwagon on Microorganisms
You can review the posts from the original Project “A” (135+ pages, divided into thirds ) by clicking one of the following:
Wisdom Gleaned from the Original Project “A” (part 1) (part 2) (part 3)
SECTION TWO – CONTROL DESIGN AND EQUIPMENT CONSTRUCTION
This is a good place to discuss the factors that influence evaporation rate, and a potential problem- – case hardening. As was mentioned, case hardening results when the layer of meat at the surface in contact with air becomes too dry, too dense, restricting outward diffusion of water. It is better to restrict evaporation rate enough that the outer layer stays somewhat moist, and therefore permeable.
You can think of the route that water takes in getting out of the sausage in terms of the following:
• Water is not generated by fermentation. However, meat has typically 75% water content, perhaps more if the packer has added “fluids” to it. This moisture is assumed to be distributed uniformly within the sausage mixture. (highest moisture)
• Water diffuses outward through the inner sausage mixture, which is assumed to be uniform in composition (high moisture) and offers negligible resistance to diffusion from the center outward.
• A small thickness of sausage meat and/or casing may possibly offer added resistance if it becomes drier than the inner mixture. (slightly lower moisture) This can become the controlling resistance in some cases, a condition called “case hardening.” Normally it offers negligible resistance to diffusion.
• A small thickness of moist air, termed a boundary layer, offers resistance. (lower moisture still, dropping off rapidly) This is the preferred controlling resistance to water diffusion, and is a function of several factors including its thickness, which is controlled by bulk air mixing rate.
• Bulk air composition (lowest moisture), which, if mixed at too great a velocity, strips off the boundary layer, allowing water to evaporate too rapidly from the outer meat layer, which results in case hardening. If the opposite condition is present, the bulk air is too humid, drying slows, and can result in deterioration of the meat.
There is a resistance to water diffusion flowrate in each of these layers. The largest resistance regulates the overall outward flowrate, and the others (having lower resistance) just keep up with that rate. Consider a river- – the water jams up at the tight spots, but flows along freely at the wide spots.
Thinking through the above, several important factors can be reasoned.
• Temperature affects water evaporation rate. It also affects water diffusion rate, but in a minor way. A nice, slow fermentation brought on by the “right” temperature is much more important. Project A called for a rapid fermentation at 68 degF for 3 days, tapering off to 57 degF for a further three months. Temperature can be thought of as the driving force for the fermentation reaction(s), but has only minor effect on water removal rate in the range that we will be using.
• Humidity, or more precisely the humidity gradient, is extremely important to prevent case hardening. Water diffuses from a high concentration within the sausage toward a lower concentration in the bulk air. If the bulk air humidity is too high, diffusion will slow down or stop and the sausage will become soggy from water buildup, and perhaps develop slime on its exterior. On the other hand, if the bulk air humidity is too low, water will diffuse too rapidly, the outer layer of the sausage will become too dry, and diffusion will slow down due to case hardening, again making the inner portion of the sausage mushy.
The rule of thumb for Project A salami calls for 85% to 90% relative humidity in the bulk air phase for the first three days, tapering off with slowing fermentation rate to the 80% – 85% humidity range. This can be thought of as the driving force for drying rate. At the end of the period, 30% to 35% of the weight will have been lost, an estimated Aw (water activity) of 65% to 70%, which makes the sausage safe to store and consume.
• One or more water diffusion boundary conditions exist which, if crossed, can bring ruin. The most significant is the boundary layer resistance, which can be thought of as that layer of air that you can see shimmering above a paved surface on a hot day. The pavement is hottest, the boundary layer of air is a cooler, stagnant layer and is hot enough that it bends (refracts) light, making it look like… well, like there’s some sort of layer there (which, in fact, there is). Above the boundary layer, the air is mobile and the light shining through it bends and wavers almost randomly, as if the stuff is flowing (which it is). The air in the bulk phase can flow in all three dimensions (left/right, forward/backward, up/down), but the air in the boundary layer can only flow in the two horizontal directions.
You can break up the boundary layer, or at least make it thinner, by blowing on it. This can be overdone, however. There is an empirical limit of one mile per hour, established by trial and error, which if you exceed, breaks down the resistance of the boundary layer and makes the outer meat/casing layer dry out too fast. Predicting this number is actually pretty complicated, and is probably subject to a wide range of uncontrolled variables like sausage composition, casing permeability, fineness of grind… (don’t ask!) Suffice it to say that if you don’t exceed the limit, you should be okay. If you do things right, the boundary layer water diffusion resistance can be thought of as the rate-determining resistance for drying rate.
But how do you measure it to make sure that your equipment is okay? Short of sticking a small anemometer into the curing chamber, which you could do in a commercial-scale chamber, you can estimate it, and you can take steps to approximate uniform velocity throughout the chamber. For example, don’t direct a fan discharge directly onto the meat. Instead, make air flow bend through a larger opening, bounce off a wall, or go through a distribution grate. Estimate flow velocity by the discharge rate (in, say, cubic feet per minute) divided by the cross-section area of the slots in the space or grate (in, say, square feet). We’ll take this up in a following section
Design Criteria: Air handling and Humidity Control
Let’s then propose some design criteria for our fermenting and curing chamber. We can do this in several stages, just in case it turns out to be a bad project or you get sent away from “home base” on an assignment or, like CW, wake up one morning in an alternate reality.
• Start simple! Start by indicating temperature and humidity only, not controlling them. External readout would be preferable. Adjust temperature and humidity (via air exhaust) manually.
• Use water makeup or periodic door opening to maintain relative humidity – may not be needed until long-term curing, and then only sparingly.
. . . . To raise humidity (to a fixed level): use CW’s salt bed w/water added. (see below for some “how to” ideas.)
. . . . To have a controllable humidity..? Start with water mist shot through the opened door? However, the salt bed method (what Ross Hill termed the “salt marsh” method) seems easiest and most reliable.
. . . . Using an external humidifier & control loop may be overkill for a small system, but could be desirable later, especially if scaled up.
. . . . External air recirculation would offer a way to add water, but it is fairly complicated to do.
• Water removal –
. . . . This could be done “Hand-o-matic”: at first. (Open door briefly) Adjust frequently during early fermentation.
. . . . Alternative: some type of as-yet-unspecified air exhaust control.
. . . . Dry air is more dense than wet air. This is because air contains nitrogen (molecular weight 28) and oxygen (mw = 32), whereas water has a molecular weight of 18. The volume of a gas is proportional to how many molecular weights (moles) of that gas are present. If you add water to nitrogen/oxygen, the average molecular weight goes down, and thus the mixture is less dense. …so let’s vent moist air from the top, and add dry air into the bottom. The effect is small, but conceptually it’s the right thing to do.
. . . . Consider having a small circulation fan, and using an aquarium air pump bubbling through a bed of the appropriate salt+water to control ingress/egress air. You’ll need a speed control on the air pump, or else a diverter valve.
. . . . External air entrance/discharge
. . . . . . . . Consider ducting circulation air out of chamber, then back in, with an adjustable leak on the discharge.
. . . . . . . . To lower humidity: Water is removed as part of drying. Due to slow humidity response, discharge only when there is high humidity inside your chamber. This might be accomplished with opening the door periodically.
. . . . Consider drying incoming air with desiccant, to avoid problems on humid days.
. . . . Better, consider bubbling air through a saturated bed of one of various salts.
. . . . “We will start out by removing air at about 2.2 MPH and drop to just a little over 1.5 by the end of 72 hours.” (This for 10 lbs of salami.) …should drop off rapidly after that.
. . . . “While the sausage is in the fermentation chamber, use the [circulating] fan only if there is moisture on the sausage.” (This may be over-cautious. If you keep the velocity low, continuous air circulation is not a problem.)
• Internal air circulation (stirring)
. . . . Rate: one suggestion: I bought a small Radio Shack 273-0240 chassis cooler fan, 12 VDC fan. 6500 RPM, 130 mA max, 1.56 watts, 7.7 cfm, 40 x 40 x 10 mm size
. . . . Runs at low speed at 6.5 volts, using an old plug-in power supply.
. . . . Fan laws http://www.nyb.com/Catalog/Letters/EL-03.pdf?gclid=CLzqp5jF8ccCFc0WHwodvQENxQ suggest that turning RPM down is linear with voltage. What is the RPM at 6.5 volts vs. design 12 volts?
. . . . May need a diffuser plate on discharge, probably on inlet too, to slow linear velocity. Aiming air against the back wall of the chamber, rather than the meat, should do. …or use a baffle (aluminum foil works).
. . . . Wet air is lighter than dry air (average molecular weight is lower). Therefore, add air at bottom, exhaust high, to promote mixing. Use a small aquarium pump and tubing.
Heating / Cooling
• Split range control may only be necessary at certain times of the year, when night/day cycle crosses desired temperature.
• Cooling control: an in-line voltage switch could be used to adjust cooling setpoint
• Heating control: T/C on/off switch to aquarium heater (I used a 40 watt soldering iron).
. . . . Where should the heating element be positioned? Near air circ fan?
• Split range: the T/C controller can be used that way. (Available inexpensively via Amazon.com.)
Combined Temperature/Humidity Measurement
• Temperature indicator integral with humidity sensor. Use an indoor/outdoor wireless system
• 2nd Temperature indicator: standalone T/C kitchen thermometer
• External air relative humidity varies with temperature. Will need a calculation in order to determine if (humid or dry) external air should be admitted or not. Example: adding air on a humid day won’t lower internal humidity.
• An inexpensive humidity controller is available via Amazon.com. Make sure that the signal can be inverted, that is, activating a relay on high humidity, switchable to activating it on low humidity. (You may need “off” when “on” is provided.)
One Possible Design
This is one of an infinite number of possibilities. I started this way. You will probably have a different one.
• The Chamber
I purchased a small “dorm-size” refrigerator for $35 at Habitat for Humanity’s “Re-Store” shop. (I purchased a second one off Craig’s List for the same amount.) The lower section is 8” deep by 15” wide by 6-1/2” high. The upper section is 14” deep by 15” wide by 6-1/2” high. A small freezer section is present but not included in these measurements.
• Cooling Control
. . . . A Johnson Controls in-line voltage switch formerly used to control a chest-style freezer as a home-brew “keg-o-rator” was installed. If the refrigerator temperature rises above a manually-set limit, power is supplied to the refrigerator. It continues running until temperature drops about 5 degrees lower, at which point it switches off.
. . . . Alternatively, the refrigerator control itself could be used, but it appears not to be as accurate as the in-line voltage switch. It also is the wrong range, which could be modified, but that’s probably a bad idea..
• Heating Control
o I purchased a four watt terrarium heater pad. It turned out to be inadequate. A 40 watt soldering iron worked better.
o Rather than purchase another in-line voltage switch, I could use the existing one to drive a 110 volt relay such that, when high temperature is sensed, the line voltage switch cuts off, turning the relay on, which would energize the heater. This would only be suitable if ambient temperature was always below desired temperature; in other words, only heating was needed. This would not be suitable for split-range control. (As it turns out, several inexpensive dual temperature controllers are available via the internet.)
• Humidity Control
. . . . Use the water/salt bed method.
. . . . Feed make-up air via a small aquarium air pump to an aquarium “bubbler stone” in a flask filled with a mixture of gravel and the required salt. The flask would be located within the chamber so as to heat or cool the air to the controlled temperature.
. . . . The air pump first used was purchased to power a venturi-type smoke generator. A smaller pump turned out to be better. These are relatively inexpensive, $12 to $30 at PetSmart.
. . . . One possible complication: during cooling cycle, the refrigerant may get cold enough to condense liquid moisture on the surface of the coils. Also, during cold weather, water may condense on the door seals. This can build up in the bottom of the interior, rendering the humidity control ineffective.
. . . . Check the makeup air contribution to air velocity: (see below)
• Air Circulation Control
. . . . I bought a small Radio Shack 273-0240 chassis cooler fan, 12 VDC. 6500 RPM, 130 mA max, 1.56 watts, 7.7 cfm, 40 x 40 x 10 mm size
. . . . It will run at low speed at 6.5 volts. This may still give too high a velocity if the air flow impinges on the sausages. I located the fan so it would blow toward the back. That way, the velocity that the sausages “see” will be the air flowrate divided by the cross sectional area of the compartment (or perhaps, the freezer compartment if you locate the fan inside it).
. . . . The humid air inlet and the heating element may need to be integrated with the circulation fan, probably with the freezer compartment, which does all the cooling. With proper baffling (by the compartment rear being open to the main compartment), combined air speed can be reduced to close to an average. (Check this.)
Chuckwagon on Microorganisms
…in which the Chuckster proceeds to scare the daylights out of you, regarding microorganisms, then adds some daylight back in on how to live with, control, and even utilize the pesky critters.
Posted: Wed Jun 15, 2011 09:37
Hi sausage makers working on Project-A!
While we are reading about bad bugs and bad manners, how about allowing me to expand just a bit on some of the material you’ve read about microorganisms and their effect on our fermented meat products and possible effects upon our bodies. I do not expect you to remember all the data I’ve presented here, I just thought I’d put the following information together for your further reading in case you’d like to know more about the bugs we are contending with. I’d like to present three pages for you to read at this point in our project. You may wish to copy n’ paste these three pages for your reference notes. The first deals with the causes of food poisoning. The second describes some of the most vicious pathogenic bacteria we have to deal with. The third page describes yeasts and molds, and such tough-to-get-rid-of microorganisms as spores and even some of the non-bacterial contamination we may encounter, such as trichinella spiralis – a microbial, nematode worm!
Food Poisoning – Page 1 –
Each year in the United States food borne diseases cause approximately 76 million illnesses and 325,000 hospitalizations*. Of this number, more than 5,000 Americans painfully suffer the clearly evident indications and symptoms of preventable food contamination, breathe their last breath, and agonizingly die! * statistics from Center For Disease Control
Three pathogens in particular – Salmonella, Listeria, and Toxoplasma – are responsible for 1,500 deaths annually. Many of the pathogens of greatest concern today, were not even recognized as causes of food borne illness merely twenty years ago! They include Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, Cyclospora cayetanensis, and others.
Other pathogenic bacteria of concern to sausage makers include Clostridium botulinum whose spores produce the deadliest toxin known to man, and Clostridium perfringens – both of which grow without oxygen present. Staphylococcus aureus is present in the mouth, nose, and throat as well as on the skin and hair of many healthy people who never suspect it. One cough or sneeze may be accountable for the sickness of countless individuals. Shigella, also a rod-shaped pathogenic bacterium, is closely related to E.coli and salmonella. Usually ingested, it is the cause of severe dysentery. Also rod-shaped pathogens of bacteria genus bacillus include Bacillus cereus, which causes a foodborne illness similar to that of staphyloccus.
We live in a microbial world in which there are limitless opportunities for pathogenic or spoilage microorganisms to contaminate food whether it is produced in huge commercial kitchens or prepared “from scratch” at home. Food borne microbes are present (usually in the intestines) in healthy animals raised for food and the slightest contact with even small amounts of intestinal contents may contaminate meat or poultry carcasses during slaughter. Others are passed along by any number of means. As a result, worldwide each year, over two million people die from diseases attributed to contamination of food and drinking water, many being painful diarrheal diseases. Even in industrialized countries, up to 30% of the population have reported suffering from foodborne diseases annually.
Recently in Europe, two and a half million pounds of beef were recalled due to salmonella contamination. In the United States, a single ice cream producer affected 224,000 persons when salmonella contaminated products were placed on the market. Earlier, an outbreak of hepatitis A, resulting from the consumption of contaminated clams, affected some 300,000 individuals in China. In the United Kingdom, two million cases, (about 3,400 cases per 100,000 inhabitants), of food contamination are reported each year. In France, three quarters of a million people (1,210 cases for 100,000 inhabitants), report food contamination sicknesses annually. Australia reports an estimated five and a half million cases of food-borne illness every year, causing 18,000 hospitalizations and 120 deaths. The problem creates an enormous social and economic strain on people in every country. In the United States alone, diseases caused by the major pathogens are estimated to cost over $35 billion dollars annually in medical costs and lost productivity.
So, why am I including this ghastly information in the midst of our sausage making project? Frankly, to scare the daylights out of you! What better place to print explicit and even graphic details in which every responsible sausage maker should become familiar before undertaking the business of feeding or preparing sausage for other people? A trusted sausage maker or cook may either promote or recklessly endanger the health of other human beings. I openly cringe whenever I hear someone repeat the words “he’s just a cook”. Inside our ranch kitchen, cowboys helped with dishes and treated the cook as if he were royalty. After all, although he was “just the cook”, all hands depended upon the “biscuit wrangler” to feed us fresh, tasty, and safely prepared food. Shucks pards, we all knew he could have easily slipped a little something extra into the chocolate pudding anytime he had revenge on his mind. We also trusted and relied upon him to help keep harmful bacteria out of the sausage and meat products we devoured like hungry wolves.
Safety n’ Savvy
Before you begin making sausages in your own ranch or home kitchen that others will consume, you MUST become familiar with the basics of food handling safety and gain at least a fundamental insight of microorganisms and their behavior. Without this knowledge, you may very easily harm someone most seriously. Making fresh sausage involves the use of immaculately clean utensils and low processing temperatures. We must take advantage of every opportunity to lower the temperature of the meat during the various steps of processing sausage. Those of the cured, cooked, and smoked variety, require the same essentials, but further include the use of sodium nitrites and nitrates, higher salt content, and of course, higher cooking temperatures. If you wish to make any type of dried or semi-dried sausage, a basic understanding of the fermentation process becomes necessary, along with an elemental knowledge of unique, acid-producing, microorganisms and their behavior. In other words, because the meat in these sausages is not cooked during preparation or even upon consumption, a bit more “bacteria savvy” is required. Further, in making those great tasting, tangy, “fermented” sausages, familiarity with a few unique safety procedures involving yeast and mold microorganisms is essential. They include at least an elemental understanding of:
1. Water activity (Aw) – a measure of how much “bound” water is available to microorganisms.
2. pH acidity – (potentiometric hydrogen ion concentration) – a measure of acidity or alkalinity in food, developing resistance against microbiological spoilage.
3. Microbiology, including:
. . . . a. molds
. . . . b. yeasts
. . . . c. bacteria of three types:
. . . . . . . . 1. pathogenic
. . . . . . . . 2. beneficial
. . . . . . . . 3. spoilage
The Major Causes Of Food Poisoning
1. Pathogenic Bacteria
Of the three microorganisms affecting food (bacteria, yeasts, and molds), pathogenic bacteria, existing virtually everywhere in our environment, remain the greatest cause of food poisoning. Sausage makers and food handlers must be aware of the strains of (a.) food spoilage bacteria, (b.) pathogenic bacteria, and (c.) beneficial bacteria. Millions of microbes may be found on unwashed hands and dirty utensils and under the right conditions, multiply at an alarmingly incredible rate.
As sausage makers, we must constantly be aware of the primary factors necessary for bacterial growth. We must also know how to change any dangerous circumstances immediately. Bacteria need merely four elements for growth:
1. moisture- Did you ever imagine that meat is comprised of three-quarters water? If we freeze the water in meat, we give it temporary defense against bacteria by “binding” the moisture. Moisture is the primary reason meat spoils. Will dehydrating meat preserve it? We’ve been doing just that for thousands of years!
2. nutrient- Meat, (mammalian muscle) consists of roughly 75% water, 19 % protein, 2.5% fat, 1.2% carbohydrates, and 2.3% non-protein substances such as amino acids and minerals. Exposed to the atmosphere, meat becomes a virtual feast for bacteria.
3. warm temperature- Bacteria thrive at body-temperature! Called the “danger zone”, the range from 40°F. (4°C.) to 140°F. (60°C.) is the optimum temperature periphery for bacteria to multiply. It is interesting to note that bacteria are restricted from growing at 130°F. (54°C.) but actually start to die at 140°F. (60°C.).
4. lack of oxygen- Aerobic bacteria need oxygen; anaerobic bacteria do not. Certain pathogenic bacteria in sausage being smoked certainly present a risk. Casings also cut off a certain volume of oxygen as does the “overnight curing” covered with plastic wrap inside a refrigerator. Remember the first rule of sausage making: Don’t smoke it if you can’t cure it! (meaning the use of actual cures of sodium nitrate or sodium nitrite).
Bacteria, have been named mostly in Latin or Greek, for their shape. Spherical bacteria are called cocci. Rod-shaped bacteria are known as bacilli. Curved bacilli (resembling a comma), are called vibrio. If they are spiral-shaped, the are called spirilla, and if the bacilli is tightly coiled, it is called spirochaetes. Many bacteria exist simply as single cells. If they are found in pairs, they are neisseria. The streptococcus form chains while the staphylococcus group together in clusters resembling grapes.
If a specific bacterium is a facultative anaerobic, it is most active in oxygen but can survive without it. On the other hand, an obligate anaerobe cannot grow in the presence of oxygen. Bacteria do not grow in size – they multiply in number. And they do it very quickly! Without oxygen, the addition of sodium nitrates or sodium nitrites is necessary to prevent botulism. It also becomes crucial that meat be removed from the “danger zone” temperature range as quickly as possible during any preparation or cooking process. This includes grinding, mixing, and stuffing sausages, procedures often supported using ice, ice water, or refrigeration and freezing. As bacteria need moisture to multiply and meat is about three-quarters water, it becomes an ideal environment for the growth of bacteria, even when it is mostly dried. However, there is a point in which meat can lose so much “available” water, it will no longer sustain bacteria. This point differs within each particular type bacterium. We’ll discuss this “water activity” later as well as another bacteria destroying process known as potentiometric hydrogen ion concentration… … or simply “pH acidity”.
Our first line of defense continues to be the application of extreme temperatures applied to meat either being cooked or frozen. As sausage is prepared, it is essential to work with only small batches at a time outside the refrigerator. Very often, meat is partially frozen before it is put through a grinder and bacteria at this temperature remain mostly inactive. In the grinder, ice chips are sometimes added to keep the temperature down as the friction of grinding actually warms the meat.
Out of the refrigerator, most bacteria begin to wake up as the temperature rises above 40°F. (4.4°C.). At 50°F. (10°C.), it is safe to work with the meat only temporarily before it goes back into the refrigerator.
At this point, salt in the amount of 2.5% – 3% is frequently added to partially restrict pathogenic and spoilage bacteria growth, as beneficial bacteria go to work producing protective acidity within time. Most bacteria thrive at the temperature of our bodies (98.6°F. / 36.6°C.). As temperatures rise much above the “danger zone”, their growth becomes restricted until around 140°F. (60°C.), they begin to die. Yet, strains such as Clostridium botulinum, may survive heating up to 250°F. (121°C) by producing heat-resistant, isolating envelopes called spores – nature’s way of protecting the organism by sheltering the bacteria from other unsympathetic environmental conditions.
– Page 2 –
Clostridium botulinum – The Killer
Clostridium Botulinum is a common obligate anaerobic bacterium microorganism found in soil and sea sediments. Although it can only reproduce in an oxygen-free environment, when it does reproduce, it produces the deadliest poison known to man – botulinum toxin. One millionth of a gram ingested means certain death – about 500,000 times more toxic than cyanide. Onset of symptoms can occur quickly and include nausea, stomach pain, double vision, and spreading paralysis, ultimately reaching the heart or respiratory organs. If treatment is given and the dose is low, half of those affected may survive, but recovery may take months or years. Although fatalities occur yearly, especially in countries where home canning is popular, the risk of acquiring botulism is very, very low. However, the lethal consequences of poisoning may make you wish to reconsider the proper addition of sodium nitrate/nitrite in your products to almost eliminate the risk. Worldwide, there are about 1000 cases of botulism each year.
The rod-shaped bacterium was first recognized and isolated in 1896 following the poisoning of several people who had consumed bad ham. It was later discovered that due to the enzyme superoxide dismutase, the bacterium might actually tolerate very small traces of oxygen. Botulinum spores are extremely persistent and will survive heating up to 250°F. (121°C), freezing, smoking, and drying. Insidiously, they lie in wait for the right conditions to occur and give no foul smell or taste, making it even more treacherous. In non-cooked fermented sausages, the microorganism must be destroyed using a combination of salt, a drop beyond 5.0 pH, and a minimum drop in Aw water activity to 0.97 or less. Placing fresh vegetables or un-sterilized (garden fresh) spices into sausage is not recommended as botulinum spores are not uncommon on leafy herbs, peppers, beans, chilies, and corn. Cut off from oxygen by being stuffed into casings and placed in a smoker, the smoking temperatures are ideal for bacteria growth. The risk using fresh garlic is less, but cases of botulism poisoning have been reported after people have eaten home-canned garlic cloves in oil – the ideal environment for anaerobic bacterial growth!
The most commonly recognized foodborne infections are those caused by the bacteria species campylobacter, salmonella, and E.coli, along with a group of viruses called clicivirus also known as the Norwalk and Norwalk-like viruses. Campylobacter remains the most common bacterial cause of diarrheal illness in the world and incredibly, most raw poultry meat has campylobacter on it. Salmonella is also a bacterium widespread in the intestines of birds, reptiles, and mammals. Its infection, known as samonellosis, typically includes fever, diarrhea, and abdominal cramps. E.coli 0157:H7 is a bacterial pathogen infecting cattle and other similar animals. Human illness typically follows consumption of food or water that has been contaminated with microscopic amounts of cattle feces. The illness it causes is often a severe and bloody diarrhea with painful abdominal cramps, but without much fever. In 3% to 5% of cases, a complication called hemolytic uremic syndrome (HUS) can occur several weeks after the initial symptoms. This severe complication includes temporary anemia, profuse bleeding, and kidney failure.
Norwalk and Norwalk-like virus (calicivirus) is an extremely common cause of foodborne illness, though it is rarely diagnosed, because its laboratory test is not widely available. It causes an acute gastrointestinal illness, usually with more vomiting than diarrhea, that resolves within two days. It is believed that Norwalk-like viruses spread primarily from one infected person to another. Infected kitchen workers can contaminate a salad or sandwich as they prepare it, if they have the virus on their hands. Infected fishermen have contaminated oysters as they harvested them.
Sausagemakers, wash your hands!
Although other routes usually transmit them, some common diseases are occasionally produced by foodborne bacteria. These include infections caused by shigella, hepatitis A, and the parasites giardia lambia, and cryptosporidia. Even “strep throats” have been transmitted occasionally through food.
Indeed, we live in a microbial world with countless opportunities for food to become contaminated as it is produced and prepared. Many food borne microbes are present in healthy animals (usually in their intestines) raised for food. In the kitchen, microbes may be transferred from one food to another food by using the same knife, cutting board or other utensils to prepare both without washing the surface or utensil in between. Worse, a food that is fully cooked can become re-contaminated if it touches other raw foods or drippings from raw foods that contain pathogens.
A “strain” is a sub-group within the species of a particular bacterium having unique characteristics distinguishing it from other strains. These differences are often detectable only at the molecular level; yet, they may result in changes to the physiology or lifecycle of the bacterium. Some strains develop pathogenic capacity becoming hostile to our food supply.
Many bacterial microbes need to multiply before enough are present in food to cause disease. The way food is handled after it is contaminated can also make a difference in whether or not an outbreak occurs. Given warm moist conditions and an ample supply of nutrients, merely one reproducing bacterium dividing itself every half hour can produce 17 million progeny in only 12 hours! As a result, lightly contaminated food left out overnight can be highly infectious by the next day. If the food were refrigerated promptly, the bacteria would not multiply at all. In general, freezing prevents nearly all bacteria from growing but merely preserves them in a state of “suspended animation”. However, this general rule has a few surprising exceptions. Two foodborne bacteria, listeria monocytogenes and yersinia enterocolitica can actually grow at refrigerator temperatures! As we shall see, high salt, high sugar, or high acid levels keep bacteria from growing, which is why salted meats, sweetened jam, and pickled vegetables are traditionally preserved foods.
Staphylococcus aureus is a particularly infamous nasty strain of bacteria that thrives at 98° Fahrenheit, causes intense vomiting, and much like clostridium botulinum, it is capable of producing toxins that remain in meat even after the microorganism is destroyed or removed. Most often found around the nose and throat or on sores, the foods most often contaminated with staphylococcus are moist and high in protein, such as meats and cheeses. The bacteria are usually passed onto food by the hands. “Staph” is even more dangerous because there is no tangible way to tell if meat is infected – taste, aroma, and appearance all seem normal. Moreover, it is highly resistant to drying and in the presence of oxygen, it can survive in Aw water levels down to an incredible 0.86. Worse, it can withstand a whopping 15% salt! Proper temperature management is essential – no, it is critical – in avoiding the spread of staphylococcus microorganisms. Cooked foods that are not cooled quickly enough or that are allowed to stand at room temperature are susceptible to infection. In fermented (not cooked) sausage, a rapid drop to less than 5.3 pH is required for its demise. In fresh or smoked-cooked-cured sausage, normal cooking temperatures exterminate the bacterium.
The rod-shaped, facultative anaerobic, E. coli (escherichia coli) bacteria are comonly but not always confined to the lower intestine of warm-blooded organisms. Most are harmless and one strain in particular has been used in the development of probiotic medicine developed to treat gastrointestinal infection. However some strains, such as serotype 0157:H7, 0104:H21, and 0121, can cause potentially lethal toxins. The strain 0157:H7 especially may cause serious food poisoning in humans, as well as other life-threatening complications. The ability of E.coli bacteria to survive for brief periods outside the body makes them ideal candidates for fecal contamination. The bacteria survive freezing and acidic environments down to 4.0 pH and a minimum drop in Aw water activity to 0.95. Untreated water, unwashed hands, flies, or vermin can then spread the bacteria. As plants are eaten, the cycle continues. As with staphylococcus aureus, it is best destroyed using heat.
Salmonella bacteria do not produce spores, are not destroyed by freezing, and are facultative anaerobic, meaning they are active in oxygen but can survive without it. This is the nasty bug that causes Typhoid Fever! In food, it is the cause of salmonellosis. The rod shaped bacteria live in the intestinal tracts of humans and animals and are passed in the excreta of an infected host. Untreated water, unwashed hands, flies, or vermin can then spread the bacteria. Salmonella can survive for weeks outside a living body and have even been found in dried excrement after nearly three years. The foods most commonly infected with bacteria are poultry, eggs, and all kinds of meat. Thorough cooking of these foods at a temperature of at least 165°F. (74 ºC) will destroy the salmonella bacterium. Each year, about 40,000 Americans are infected with food borne salmonella and develop salmonellosis. Amazingly, another 142,000 are annually infected with Salmonella enteritidis solely from consuming raw chicken eggs! About 30 die. In non-cooked fermented sausages, the microorganism must be destroyed using a combination of salt, a drop to less than 3.8 pH, and a minimum drop in Aw water activity to 0.94.
Clostridium perfringens bacteria, like salmonella, is present in the intestines of humans and animals, but like clostridium botulinum, it is an obligate anaerobic and cannot grow in the presence of oxygen. The bacteria forms spores that survive very well in soil – thus vegetables may carry the organisms. Clostridium perfringens bacteria are most commonly found in raw foods, especially meats and poultry, and proper temperature management is fundamental in avoiding the spread of the microorganisms. In non-cooked fermented sausages, the bacteria must be destroyed using a combination of salt, a drop to a point less than 5.5 pH, and a minimum drop in Aw water activity to 0.93.
In October 2002, a major poultry producer in Franconia, Pennsylvania, recalled more than twenty-seven and a half million pounds of turkey and chicken “ready to eat” products they had already placed on the market. Following an outbreak of listeriosis, several other meat companies voluntarily shut down operations until the source could be identified. Unfortunately, listeria infection (listeriosis) in several northeastern states had taken its toll, initiating several deaths, sicknesses, miscarriages, and stillbirths.
Each year in the United States, an estimated 2,500 persons become seriously ill with listeriosis. Another 500 die, causing listeriosis to be the leading cause of death from food borne bacterial pathogens! Twenty to thirty percent of infections result in death! Listeriosis infection is caused by eating food contaminated with the bacterium Listeria monocytogenes. Pregnant women are twenty times more likely to contract listeriosis than other healthy adults and account for a third of all reported cases. The elderly, and persons with weakened immune systems due to cancer, diabetes, kidney disease, and other diseases, are especially at risk.
The rod-shaped Listeria monocytogenes bacteria do not produce spores and are found in soil and water. Most often, the bacteria get into food using manure as a fertilizer from animals having the infection yet displaying no ill symptoms. The bacterium is destroyed by heat while cooking or preparing food. Uncooked meats and vegetables and unpasteurized (raw) milk or foods made from unpasteurized milk may contain the listeria monocytogenes bacteria. Foods to be concerned about include soft cheeses and cold cuts at the deli counter, and many ready-to-eat foods such as hot dogs and raw vegetables. These items must be thoroughly cooked until they are steaming hot! Check the labels on Feta, Brie, and Camembert, any blue-veined cheeses, and Mexican cheeses such as Queso Blanco, Queso Fresco, and Panela. Unless labels clearly state they are made from pasteurized milk, avoid them. It is always a good idea to eat smoked seafood only in cooked dishes such as casseroles.
Whenever making fresh sausage from any raw meat, protection from listeria monocytogenes is dependent upon cooking the meat until the recommended internal meat temperature of at least 152°F. (66.6°C.) is reached. In non-cooked fermented sausages, the microorganism must be destroyed using a combination of salt, a drop to less than 4.4 pH, and a minimum drop in Aw water activity to 0.92. Sausage making is completely safe only when the rules are stringently followed.
It is now estimated that half of the chickens produced in America contain the spiral rod-shaped campylobacter jejuni microorganism that infects 13 persons in one hundred thousand. The bacterium does not produce spores. World wide, it affects about two and a half million people annually or 0.8% of the population. Most people who become ill with campylobacteriosis get diarrhea, cramping, abdominal pain, and fever within two to five days after exposure to the organism. The diarrhea may be bloody and can be accompanied by nausea and vomiting. The illness typically lasts one week. Although comparatively few people die from the disease (about 125 each year), the symptoms are harsh and painful, usually requiring medical attention. Many chicken flocks are infected with campylobacter but show no signs of illness. In non-cooked fermented sausages, the microorganism must be destroyed using a combination of salt, a drop to less than 4.9 pH, and a minimum drop in Aw water activity to 0.98. Campylobacter may be easily spread from bird to bird through a common water source or through contact with infected feces. When an infected bird is slaughtered, campylobacter organisms are easily transferred from the intestines to the meat.
Reactive arthritis is autoimmune condition that develops in response to an infection in another part of the body. People developing an infection having come into contact with Shigella bacteria, often devolp severe dysentery and reactive arthritis. Infection is made though fecal-oral contamination and as few a ten cells may trigger the disease shigellosis. The rod-shaped bacterium does not produce spores, is closely related to E.coli, but is found naturally only in man and apes. It does not affect other animals. In non-cooked fermented sausages, Shigella bacteria must be destroyed using a combination of salt, a drop to less than 4.0 pH, and a minimum drop in Aw water activity to 0.91.
Bacillus cereus is a rod-shaped bacterium that develops spores. Some strains are harmful to humans when survival of bacterial endospores takes place whenever food is improperly cooked. This problem is compounded when food is then improperly refrigerated, allowing the spores to germinate. Infection causes severe nausea, vomiting, and diarrhea. In non-cooked fermented sausages, bacillus cereus must be destroyed using a combination of salt, a drop to less than 4.3 pH, and a minimum drop in Aw water activity to 0.91.
Other strains of bacillus cereus can be beneficial as probiotics. The bacteria are facultative anaerobic (most active in oxygen but can survive without it) and are found mostly in the soil. The bacterium is difficult to identify, as it closely resembles staphylococcus aureus and other pathogens. Bacillus cereus is also known to cause problematic skin infections in humans that can be quite damaging, and difficult to eradicate.
2. Food Spoilage Bacteria
Mother Nature has always employed an efficient and practical means for reducing and eventually eliminating waste. Surplus organic material (without preservatives) no longer needed or not consumed while fresh, simply wastes away with the infection of several types of bacteria. Most often, a product simply falls apart and eventually disintegrates. Meats spoil by food spoilage bacteria breaking down proteins and fats. Brochotrix thermosphacta, pseudomonas spp., or a host of other spoilage-type bacteria, usually cause not only slime and discoloration, but also objectionable odors, terrible tastes, and intolerable textures as well. Each has its preferred temperature range for quick reproduction and some are most active inside a refrigerator. Others are active at room temperature or even smokers, heated up to 140°F. (60°C.). Although spoilage bacteria may not be life-threatening, they may certainly make life miserable for a week or two, if ingested in spoiled food. How do we stop food spoilage bacteria? Sometimes we can’t before it does its damage. However, most cannot survive a drop below Aw 0.85. Dried foods? Most are very palatable but not always preferred or practical.
You may wonder how the Great Plains Indians kept fresh buffalo meat from spoiling. Without salt, and plenty of it, bison jerky did indeed spoil! Rarely did they have freshly killed meat as an alternative to tough, chewy, dried buffalo jerky and most often it had to be soaked a few hours just to relieve enough of its salt content to make it palatable.
Although the spoilage bacteria is unpleasant, it is the pathogenic bacteria with which we are most concerned, as its presence in contaminated food is not always made evident by irregular odor, color, texture, or other normally perceptible means.
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Microorganism Type 2. (Yeasts)
It is estimated that only 1% of all yeast species have been described. Yeasts are microscopic fungi that grow as single cells. They will grow on the surface or near the surface inside non-cooked, air-dried, fermented sausages, while molds grow only upon the surface. Neither yeasts or molds are affected by the pH drop during the fermentation stage of sausage making and as long as a high degree of humidity is sustained, they will grow within a wide temperature boundary. However, the two microorganisms grow much slower than bacteria and during the drying process, they develop much later. Both yeast and molds are entirely part of traditional sausage making as both metabolize some of the lactic acid created during fermentation. Increasing the pH, thus lowering acidity, the flavor of slowly fermented sausage is greatly enhanced. Yeasts are not as sensitive to increased levels of salt as are lactic acid bacteria and they need little oxygen to survive. Two yeasts especially tolerant of salt are Debaromyces hansenii and Candida formata.
Unlike bacteria, there are no known species that grow only anaerobically (obligate anaerobes). Yeasts grow best in a neutral or slightly acidic pH envirnment but are able to grow in foods with a low pH, (5.0 or lower) and in the presence of sugars, organic acids, and other easily metabolized carbon sources. During their growth, yeasts metabolize some food components and produce metabolic end products. This causes the physical, chemical, and sensory properties of a food to change, as the food is spoiled. The yeast of the Zygosaccharomyces genus have long been associated with the food industry as a spoilage yeast. These species are able to grow in some of the more commonly used food preservation concentrations including ehanol, acetic acid, sorbic acid, high sucrose, benzoic acid, and sulfur dioxide.
Microorganism Type 3. (Molds)
Molds are microscopic fungi that grow in the form of multicellular filaments called hyphae. Ubiquitous in nature, molds are aerobic and grow on the surface of sausages. Wild growing “white” molds have been used for centuries on sausage surfaces to help prevent oxygen from penetrating the sausage and to help regulate or temper the drying cycle. Mold also oxidizes lactic acid – increasing pH, and it consumes oxygen to produce catalase, thereby reducing lipid oxidation and rancidity of fats. Penicillium nagliovense in particular, promotes lipolytic (breaking down of fats) and proteolytic (breaking down of proteins) development, greatly improving the flavor of fermented, air-dried sausages. In order to grow, molds need 75% humidity or more and higher temperatures facilitate their development. The sausage maker’s favorites include penicillium nagliovense and Fleming’s penicillium chrysangenum, from which the miraculous antibiotic penicillin was developed.
Spores And Mycotoxins In Molds
Some molds also produce spores and subsequently, mycotoxins. When mold spores are present in large quantities, their mycotoxins can certainly present a health hazard to humans and animals, potentially causing allergic reactions and respiratory problems. Exposure to (or consumption of) high levels of mycotoxins can lead to neurological problems and in some cases… death! Molds of color, especially green, should be wiped away with vinegar immediately. Although it is generally accepted that wild white mold is safe, it yet remains a wild mold and therefore its safety remains a gamble. For this reason, it is suggested that starter cultures, purchased from a reputable company, be used in sausage making to control microorganisms. I prefer and recommend the very fine Chr. Hansen Bactoferm™ products made in Denmark and distributed in Germany. To start a mold culture on sausage, most sausage makers dip them into a solution just before they go into the fermentation room or chamber having raised temperature and higher humidity – ideal growing conditions for fungi. I like to spray them using an atomizer. And yes, you really should put a little ventilation into your curing chamber. A couple of well placed 30-30 rounds should do the trick!
There will always be skeptical ol’ timers and hardy, dogmatic ol’ folks who may say, “We’ve never used that ‘newfangled bio-culture stuff’ to make salami – our good ol’ mold has been successful for years, and we haven’t killed anybody yet, so what’s the big deal”? Well, I have but one question… and I’ve wondered about it for some time. Just how many folks over the years have died of “natural causes”?
How Bacteria Multiply
Microorganisms do not grow in size – they multiply in number. And they do it very quickly! Lets take a look at the bacteria count of two particularly infamous nasty strains – E.coli 0157:H7 and staphylococcus aureus – both bacteria thrive at 98° Fahrenheit. It is crucial that meat be removed from this temperature range as quickly as possible during any sausage making preparation or cooking process. Because staphylococcus aureus bacteria are most often found around the nose and throat or on sores, and the foods most often contaminated with staphylococcus are moist and high in protein (such as meats), hands must be scrubbed, a hairnet or hat worn, and any contact with the mouth, nose, or acne sores etc., must be eliminated. Coughing or sneezing is inexcusable and indefensible during any phase of the sausage making process! The bacteria are usually passed onto food by the hands. “Staph” is even more dangerous because there is no tangible method to indicate whether the meat is infected; the taste, aroma, and appearance all seem normal. Proper temperature management is not only necessary, it is critical in avoiding the spread of staphylococcus microorganisms. Cooked foods not cooled quickly enough or are allowed to stand at room temperature too long, are susceptible to infection. How quickly do bacteria develop? Left on a table top on a warm late spring day, bacteria actually double each twenty minutes! In other words, E.coli and Staphylococcus aureus bacteria in “sterile meat” may easily number above 25,000 in three short hours without refrigeration. Worse, if the meat is ground into burger, the increased surface area increases the risk exponentially!
Non-Bacterial Contamination – (Parasites)
Trichinella spiralis is a parasitic roundworm whose larval form may be present in the flesh of pork or wild game and its painful infection is known as trichinosis. The best way to irradicate the dangers of the trinchinella spiralis larva is to simply cook the meat thoroughly. However, not all sausagemaking procedures allow the meat to be fully cooked or even cooked at all. In these cases, “certified pork” must be used; pork that has been deeply (sub-zero) frozen for a prescribed amount of time. Because of new USDA regulations in American hog production during the 1970’s and 80’s, the disease in modern America has mostly been eradicated. For decades preceding the new rules, many hog producers fed hogs the entrails of other butchered hogs as the cycle continued until the modern rules were put into effect. By public demand over an extended period of time, American pork has become less fatty and mostly trichinae free. It is interesting to note that in England, as well as in many other hog producing countries, trichinella spiralis is virtually unknown.
Always follow the recommended cooking temperatures in recipes. The internal temperature of cooked fresh pork must reach at least 150 ºF. (65.5 ºC.) All hot smoked sausages should be cooked to 155 ºF. (68 ºC.). Cold-smoked or air dried sausages, whose formulas contain Prague powder #2, should be cooked to 120-135 ºF. (49-57 ºC.). Never judge by looks alone, whether meat is cooked sufficiently, and always check the internal temperature using an accurate meat thermometer.
Cryptosporidiosis is a diarrheal disease caused by the microscopic parasite cryptosporidium paryum. Both the disease and the parasite are known as “crypto”, and there is no effective treatment or cure for the nasty stuff. The parasite lives inside the intestines of humans and animals and is passed in the stool of both once infected. Most people with healthy immune systems will recover on their own having been infected. So why is it such a concern? Many people affected with other diseases as cancer etc., have weakened immune systems. Worse, the Crypto parasite has a protective outer shell allowing it to survive outside the body for long periods and makes it very resistant to the chlorine disinfection of any city’s water supply. Within the past two decades, cryptosporidium paryum (“crypto”) has become recognized as one of the most common causes of waterborne disease (drinking and recreational) in humans in the United States. The parasite is found in every region of the United States and throughout the world. Millions of Crypto bacteria may be released in just one bowel movement of an infected human or animal. People may become infected after accidentally swallowing the parasite inside a recreational facility as a swimming pool or by simply eating uncooked food contaminated with cryptosporidium paryum. As food is prepared with water taken from a “chlorinated and disinfected” city’s reservoir supply, Crypto yet thrives. Cooks must destroy any possible contamination by completely cooking any food. How much heat? The USDA recommends at least 152 degrees F.
“Declaring War On The Bugs”
How are we to defeat pathogenic and spoilage bacteria in sausage? Is it possible to starve them? What about salt? How much should we use? We also know that bacteria cannot survive in an environment without moisture, so may we limit the amount of water available to bacteria to destroy them?
All good questions! However, contrary to popular certainty, salt does not destroy bacteria. It doesn’t even force water to evaporate. It does, however, immobilize or bind a specific amount of free water, preventing it from interacting with bacteria (or anything else). The measurement of “bound” water (not available to bacteria) is called “water activity”, and is abbreviated Aw. How about serving a bacterium a dose of salt at first, while we deprive it of moisture? It works. For thousands of years, it has worked! How did your grandparents preserve fresh pork hams and bacons? Perhaps they were pioneers heading westward across the plains in a wagon with bacon, hams, or other cured meats in the larder. Salted hams were dried then “revived” in water before use. Bacon was cured with salt, smoked, and par-cooked. Your grandparents certainly knew that salting and par-cooking meats were positive steps adverse to microorganism survival! They were also aware that if they smoked meat, it not only tasted better but it was not likely to develop mold on its surface. Of course, they had to soak the salt from the flesh just to make it palatable. Nevertheless, it was meat – consumed along the trail, months after it had been initially prepared.
How about introducing acidity as protection against pathogenic and spoilage microorganisms? Bacteria hate acidity, right? But how much is enough? Doesn’t acidity affect the taste of the final product? It’s true, another effective method of preserving meat involves acidity introduced by various means. Of course acidity affects flavor and the addition of an acid is not just a simple resolution for every type of meat. Yet, without lactic acid – producing bacteria, we wouldn’t have wonderful, fermented type sausage. As we lower the pH factor, we increase acidity. Are microorganisms able to survive inside acidic foods? Not when the acidity is increased in a sausage by a drop below 4 pH. Lets investigate a most effective way of preserving non-cooked, fermented sausages such as salami and pepperoni, using lactobacillus or pediococcus – lactic acid bacteria.
pH – The Measure Of Acidity
Roughly, pH is the measurement of acidity or alkalinity in any substance using a scale from zero to fourteen. Pure water is said to be very close to neutral, having a pH nearly 7.0 at 77° F. Foods with pH less than 7 are said to be acidic, while foods having a pH greater than 7 are said to be alkaline or “base”.
Aw The Availability Of Water
Not all the water in the cells of meat is available to microorganisms. Some of it is “bound” by salt, or other restrictive elements as sugar. The remaining water is known as “free water” and it is the only moisture available to bacteria as well as yeasts and molds. By adding salt or sugar to a sausage, we are able to restrict the amount of “available water” to pathogenic bacteria. Unfortunately, it also restricts available water to beneficial bacteria as well. Freezing water into ice is simply another method of “binding” or keeping water restricted from harmful bacteria. The measurement of “bound” water (not available to bacteria) is called “water activity” or Aw. Water Activity is measured on a scale from 0.00 (called “bone dry”) to 1.00 – the measurement of pure water. Adding salt immediately binds a large amount of water.
Sterilized Spices In Sausage
The risk of bacterial contamination is the primary reason the meat industry uses only extracts of spices in cured meat products. In Europe, most dried spices are irradiated with intense gamma rays before packing, effectively killing the spores. Although irradiation for meat was approved in the 1990’s under the Clinton administration, it has been slow to catch on in the United States. The U.S.D.A. recommends the long-established procedure, and declared it to be entirely safe. Herbs and spices freshly picked and plucked from your own garden are fabulous when washed and prepared in foods for immediate consumption. However, a little fresh, non-sterilized basil or oregano, fresh from your prize-winning garden, may rapidly spoil jerky or meat used for sausage in a matter of only a few hours, producing any number of bacteria types. Whenever storing meat overnight for casing sausages, fresh spices will invariably begin to produce pathogenic and food spoilage bacteria, quickly devastating your product. For health’s sake, it is of utmost importance that you use only sterilized spices and herbs purchased from a reputable company, in making sausage.
Is bacterial contamination the only type of food poisoning? Absolutely not. Consider the toxins of poison mushrooms. Many are fatal. Recently in Salt Lake City, an entire Vietnamese family was tragically poisoned having made a mushroom soup from wild mushrooms found in a nearby canyon. Consuming the soup in one picnic meal on an outing, the entire family agonizingly died. Each year, many people become ill having eaten poisonous reef fishes, me included! Pesticides claim their toll also. Similarly, fresh fruits and vegetables can be contaminated if they are washed or irrigated with water that is contaminated with animal manure or human sewage.
3. Beneficial Bacteria
Binding available water (Aw) in sausage effectively confines it to a point where harmful pathogenic bacteria are no longer able to survive. The process is known as dehydration or limiting water activity. For centuries, this process, along with the chance addition of lactic acid-producing bacteria to increase acidity, has been responsible for safely preparing air-dried, fermented, sausages. Today, by adding carefully chosen strains of lactobacilli or pediococci, reducing the pH acidity to safe levels in fermented sausage has been most effective in destroying competing pathogenic bacteria. Historically, as the sausage maker unwittingly created ideal conditions for competing beneficial bacteria to thrive, pathogenic bacteria were deprived of nutrients, being literally crowded out of the way. Providing optimum temperatures and relative humidity for any number of previously unknown lactobacilli and pediococci bacteria, safe and tasty fermented air-dried sausages have been crafted for hundreds of years. Only since about the middle of the nineteenth century has man known what was actually taking place inside the fermentation process. Without beneficial bacteria declaring war on pathogenic bacteria, we would not have salami, pepperoni, summer sausage, or any number of other tangy, fermented air-dried sausages.”
The staphylococcus genus includes thirty-two species and eight sub-species. Staphylococcus Aureus remains one of the most dangerous pathogenic bacterium known and can even survive an incredibly massive dose of fifteen percent salt! However, at least one of its strains has proven to be beneficial by promoting color fixing and flavor forming qualities in air-dried sausages. Closely related to Micrococcus, the two micro-organisms provide beneficial qualities to fermented air-dried sausages.