The differences between the various types of dry-cured salami are due to the kind of meat they contain, the proportion of lean to fat, spices or the lack thereof, and the fineness or coarseness of the grind is what distinguishes one regional Salami from Another. Italian salami are different from region to region; they can be un-smoked or smoked, each with their own formulas, curing and maturation. The Salami of Toscana has large cubes of fat and coarsely ground meat, that of Lombardia has an ubiquitous consistency of lean to fat, those of Calabria are redolent with hot pepper. Salami can be exclusively pork, or be a mixture of pork and beef, but they can also be made with venison or other game meats, poultry, goose, lamb, donkey, horsemeat and goat.

Generally speaking the salami of northern Italy is heavily molded on the outside, whereas those of southern Italy are generally cured in a way that produce a light mold covering or none at all. These molds, like those on fine ripened cheeses, impart a complexity of flavor to the salami. Generally, I prefer a ratio is 70% lean and 30% fat, but that may vary depending of the recipe or style being made. There are two types Italian salami most familiar to Americans. The fine-grind type of salami that is similar to that made in Milan containing black pepper; the other is Soppressata, a coarse grind salami, often with red pepper, similar to the type found in Naples. 

The information on the following page is the result of my experience in a San Francisco, California Salami Factory (Columbus Salami) owned by my relatives for 60+ years. My experiences range from work in the sales and shipping departments, production kitchen, manufacturing floor, fermentation rooms, aging rooms and quality control laboratory, primarily in our San Francisco factory, later in our South San Francisco production facility.

The Production of Fermented Dry Salami:

Background:

Salami production has always been due to the presence and life activities of lactic acid bacteria in the meat and the meat preparation area. In the past, salami making was thought of as an art because sausage makers did not have an understanding of the effect of bacterial growth in the meat paste. Meat was chopped, salt was added along with spices and the salami maker had a protocol to follow that produced an edible product...most of the time! The indigenous bacterial contaminants worked their "magic", but the results were not always successful. If the bacteria activity resulted in a high pH, spoilage bacteria could grow and, in the worse case, pathogenic bacteria had a population explosion in the salami.

With research in the academic institution, bacterial growth and fermentation processes we elucidated and "starter bacterial cultures" became available for commercial production which resulted in a uniform and consistent product. With the introduction of starter cultures, salami production became less of an art and more of a science.  It is now know that a large family of bacteria, the lactic acid family, is essential for good, consistent product development. However not all lactic bacteria are desirable; some prefer to live in an oxygen rich environment, while other prefer anoxic environments. It seems that this group has very specific substrates that they rely on for food.  Some produce buttermilk from milk sugars and others produce cheese and others produce yogurt. Some like certain starches and produce the flavor complexity of sour dough bread, others like wheat and barley and contribute to the flavor of beer,. A small group prefer to live in ground meat and convert glucose to lactic acid! Those are the ones we use to make salami!

The Meat Paste:

Regional traditions dictate the types of meat and fat used in the manufacture of salami. I prefer to use pork shoulder butts when the recipe calls for pork, beef chuck when beef is used. For fat, I prefer to use what is termed pork back fat, which is the fat trimmed of the top of loin area along the back of the pig; another choice would be "fat bellies", the same cut of meat used to make bacon. Other choices are pork jowls and beef cheeks! As mentioned previously the pork meats should be pre-frozen according to the schedule outlined by the USDA--in the business, this is referred to "certified pork"--which means that the pork has been certified by the on-site government meat inspector and meets all the USDA requirements.

Remove and discard as much sinew as possible from the meats. The dimensions of the grind will depend upon the style of salami you wish to make; for example, to make Soppressata or a Toscano style, choose a medium to large grind, whereas, a Milan style would require that the meat require that the meat be ground to a fine grain. I prepare the meat by cutting it into 1 to 1-1/2 inch cubes.  (This is a convenient size for my #22 grinder throat, but you can adjust this to fit your grinder.) Then I put them in the freezer until they are partially frozen; then I grind them to the desired consistency, returning them to the freezer while I prepare the fat, which I handle the same way. An infra-red/laser thermometer is useful here because nothing touches the meat and cross contamination is avoided. These are relatively inexpensive (about $25) and easy to use.  So many steps are involved in producing a successful product that you must keep written records relating the meat to fat ratio, size of the grind grinder plate, temperature, etc. If you have access to a pH meter or pH paper, it is helpful to record the pH at this time and again after fermentation is complete.  There are many types of pH papers on the market.  Be sure to get one with a narrow range for a more accurate reading...generally the best are measure pH from 4.5 through pH 7.5 (5.5-8.0 is OK) Prices vary a lot but you shouldn't have to pay more than $6 a roll! These notes will be invaluable in evaluating the final product The preparation of the meat paste begins with grinding the raw materials.

Meats that are chopped or are a medium or large grind can be mixed fairly aggressively since the final product will not have a homogeneous texture of fat to lean. However, the fat in fine ground pastes can  become excessively smeared during the mixing and blending stage if it is not kept very cold. Of the many variables in making salami, one of the most important is the temperature of the fat and the meats. The meats used in salami making should be kept at a temperature range of 36°F to 40°F in order to minimize the growth of harmful microorganisms (brought on by butchering and handling the meat) and keep the fat from melting and smearing in the product. Generally speaking, when preparing your own formulations, remember to compensate for the fat in a pork shoulder (often called Boston butts) which can contain approximately 17 - 20% fat.   If you are using game meat, many people find the taste of the fat (what little there is) objectionable...you can trim it off and substitute pork fat!  If you have access to a butcher that prepares primal cuts from slaughtered animals, you may be able to order bull or cow meat; not only because it generally cost less, but because the biochemical makeup of the muscle meat from older, leaner beef animals is best for making salami. The general procedure is to chop or grind the meat first, then add the sugar, spices, additives and dissolved starter culture and mix them evenly into the paste. Mixing should be done under the most strict sanitary conditions; if you mix by hand, use sterile latex surgical gloves to prevent cross-contamination and to protect your skin from absorbing the chemical additives!  I have a small stainless steel sausage mixer that I purchased from Northern Tools for $100 that holds about 18 lb. of meat...It works very well and keeps your hands clean! Add the almost frozen fat so as to maintain good differentiation between the red meat and the white fat.  Finely, add the salt; the late addition of the salt minimizes its absorption. The salt immediately begins reacting with the muscle proteins; the result is the formation of sticky myosin molecules (see the "INTRODUCTION" pages for more information). The additives need to be well amalgamated into the meat paste for the sausage to have a consistent cure and taste throughout.  Immediately after mixing the meat with the salt,  the meat paste begins its transformation to salami.  Before we get to the stuffing and incubation stages a few words about additives and starters are in order.

Sugar: Essential to the process of making fermented dry cured sausages is the presence of sugar in the form of glucose (often called dextrose). Glucose is a sugar that contains carbon hydrogen and oxygen atoms with the general formula of C₆H₁₂O₆ The lactic acid bacteria (LAB) get their name from the fact that they convert glucose to lactic acid, which in turn lowers the pH in the meat mixture.  This has the effect of inhibiting the growth of less desirable bacteria. Sugar in animal muscle is in the form of a starch called glycogen and is not immediately available to the bacteria as a food source so glucose must be added to get the process going; however, other carbohydrates may also be added in some formulations such as maltodextrin, lactose or sucrose. All these carbohydrate can easily be broken down into glucose by LAB.

 

GLUCOSE          [               LACTIC ACID    +    ENERGY    C6H12O6            [               2 CH3-CHOH-COOH  +  2 ATP

Salt: The salt is essential because it is involved in the biochemical activities we call curing as well as the inhibition of some microorganisms found in the meat. Because LAB are salt tolerant, they get a jump start over less desirable salt intolerant microorganisms. Contrary to common belief, it is the salt the only ingredient that is essential to "cure" or preserve the meat, not the nitrite/nitrate "curing salts". The salt makes the proteins in the meat soluble, causing a sticky film (myosin) to form around the fat particles which in turn creates a stable emulsion. The addition of salt to the meat alters the osmotic pressure of the muscle cells and causes the dehydration of the meat paste which also prevents growth of food-spoilage microorganisms. The use of salt alone would produce a harsh, dry and overly product with an undesirable dark color, therefore other additive to the meat paste help improve the appearance and taste of the product. The usual amount of salt added is generally between 2-3% by weight.

Nitrite: In addition to the salt, nitrite is added for the inhibition and the selection certain bacteria found in the meat. In dry cured products, a mixture of both nitrite and nitrate are added to the meat. As stated on the "INTRODUCTION" page, it is desirable to select and add lactic acid producing bacteria to the salami paste. more on this topic follows. You sometimes see formulas that call for saltpeter (potassium nitrate). Saltpeter concentration is difficult to control in small amounts and it is very easy to overdose. The current trend is to move away from saltpeter and use sodium nitrite/nitrate mixtures. In reality, the nitrate, to be useful in curing, must be converted to nitrite...this is accomplished by bacteria (Micrococcus, for example) present in the meat paste. Nitrite is used up quickly in the curing process so a mixture of nitrate and nitrite is added to dry-cured meats to ensure a supply of nitrite in the later stages of maturation. In addition it keeps the meat an appealing red color. Nitrite reacts with myoglobin and is an essential for the development of characteristic red color in preserved meats.  It is quickly used up so another sodium compound (nitrate) is added along with the nitrite.  An enzymatic reaction (caused by nitrate reductase) converts nitrate to nitrite. The reductase is produce by a common bacterium (Micrococcus) found in the meat or the bacteria may be added during production.

nitrate reductase Sodium nitrate            [           Sodium nitrite        Na+ [NO3]-            [                 Na [NO2]-

The nitrite is particularly effective in the inhibition of Clostridium bacteria, which causes botulism. This microorganism  produces a very powerful neurotoxin (nerve poison) that is the most toxic of all naturally occurring substances. The incidence of the disease is low, but the disease is of considerable concern because of its high mortality rate if not treated immediately and properly. When it is ingested it causes paralysis. if left untreated 12 or more hours, the lungs can be paralyzed and death occurs. Botulism is usually associated with consumption of the toxin in food. It can exist as a living organism or spore in contaminated food. The animals most commonly affected are wild fowl and poultry, cattle, horses and some species of fish. Sausages, meat products, canned vegetables and seafood products have been the most frequent vehicles for human botulism. The organism is very resistant to heat and other treatments. Because naturally occurring levels of spores are low, cellular growth is required to produce the toxin. C. botulinum can grow under the anaerobic (no oxygen) conditions found in dry-curing sausages and salami. The neurotoxin is heat labile and can be destroyed if contaminated foods are heated at 80°C (176^oF) for 10 minutes or longer.

Starter Cultures: Many foods that we enjoy, such as, cheeses, yogurt, beer, and sourdough bread to name a few are the result of bacterial fermentation. The lactic bacteria used in salami making are salt tolerant and produce lactic acid from the glucose (dextrose) in the meat paste, which has the effect of lowering the pH (or raising the acidity). 

I recommend the use of a starter culture in order to control the myriad of microorganisms that may be present in ground meat, especially food-spoilage and pathogenic microorganisms. The purpose for using them in my opinion is twofold: they enhance product safety and enhance product quality. The environment of the meat is quickly acidified making it a hostile place for pathogenic and spoilage bacteria to grow. The rapid increase in acidity inhibits the water bind ability of the meat and makes for a more consistent drying process. See the discussion of water-activity (A_w) in the "TIPS" page.

Starter cultures can be difficult to find in small quantities. At one time they were available only for commercial use, but now they are now available in small packets for the home sausage maker.  I currently use a number of freeze dried starter cultures produced by Chr. Hansen North America.  They are available from several sausage making suppliers and can be purchased over the internet. Each type produces slightly different subtle flavors and can be used through a specific range of incubating temperatures.

I’ve used several species Pediococcus, Staphlococcus, and Lactobacillus. These microorganisms are available in various mixtures and I refer you to the charts on my "INTRODUCTION" page.  My choices are based on their optimum incubation temperature and flavor production. I like Bactoferm LHP whose optimum growth is obtained between 80-100ºF.  It contains a mixture of Pediococcus acidilactici  and Pediococcus pentosaceus).  Bactoferm F-RM-52 shows optimum growth between  70-90ºF. It is a fast acidifier that is a mixture of Lactobacillus sakei and Staphylococcus carnosus. Bactoferm T-SPX is my favorite for northern Italian style salami and shows optimum growth at 75^oF. It is a mixture of Pediococcus pentosaceus and Staphylococcus xylosus). The Lactobacillus and Pediococcus in these last two mixtures are the acid producers and the Staphlococcus is the flavor and nitrate reductase producer.

Spices: The purpose of the spices is to impart the desired the taste and aromas that the salami maker prefers. These aromatic plant substances can be used in their natural form, oils or extracts and give color or flavor to the product. They can be used whole, cracked or ground. Spices like garlic and pepper contain antioxidants and help prevent rancidity. In the majority of the cases, Italian salami is often flavored with black pepper, cracked or ground, wine infused with crushed garlic, red pepper or fennel seeds. Other formulations may have mace, cinnamon, clove or nutmeg. It is absolutely essential that you use fresh spices for consistent results.  If your ground spices are more than 6 months old, through them out and purchase new ones.  It is always better to purchase whole, un-ground spices and grind them yourself as needed...you'll be surprised by the difference!

The meat paste is stuffed into casings and tied. The casing used must allow moisture  to escape the salami throughout the manufacture. The choices for casings are astonishing. They fall into two categories: natural and artificial. The artificial casings can be collagen (some edible others not) or fibrous; the natural can be intestine, bladder, stomach or esophagus from beef, pork or sheep.  In Europe, horse and donkey innards can also be used in some countries.

For salami, I prefer to use a natural casing called a "beef middle". The size I use makes salami of 2-1/2 inches in diameter, stuffed. They are packed in salt and will keep for many months in the refrigerator. I like to use natural casing for two reasons: they give the salami an "old world" look and because the are edible, they contribute to the overall taste of the salami. I also believe the salami dries more evenly and consistently with natural casings.  If you're going to spend money for casings, you might as well get the kind you can eat!  The advantage of artificial casings are that they are easy to store, they are a consistent size, and they don't smell!

 

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The Maturation Process:

In my opinion, the maturation of salami can be thought of being subdivided in three distinct phases: Curing, Incubating, Drying...all of which require different temperatures and relative humidity conditions. Depending upon the type of product that is intended, this process may last  21 or more days Once the meat is ground or chopped and all the additives have been added and mixed, the maturation process of salami production can be thought of being subdivided in three distinct phases: Curing, Incubating (Fermentation), and Drying (Aging); each of these phases require different conditions of temperatures and relative humidity. Depending upon the type of product that is intended, this process may last  21 or more days.

I. The Curing Phase:

This is the beginning of the maturation process. This phase begins immediately upon the addition of salt. In the old, traditional method, after grinding and mixing, the paste was put under refrigeration for "holding period" of approximately 24-48 hours to cure. The differences in time depended upon the recipe being used or available space in the production facility. As I mentioned before, not much was known about the science of the curing process. In those days manufactures considered salami making an art developed over centuries of tradition and did not know that curing was due to the presence of salt interacting with the indigenous bacteria in the chopped meat.

In the modern production of salami, this refrigeration period has been replaced by immediate fermentation at 85oF or higher because bacterial starter cultures are added to the meat paste. The high temperature is necessary to "jump start" the production of acid.  During this phase it is essential that the parameters of proper temperature and humidity and time constraints are maintained so as to maintain consistent acid production so the pH remains in the 4.5-5.0 range. The appropriate temperature and humidity will be dictated by the species requirement of each microorganism in the starter culture. This has the effect of raising the acid content of the meat to a point where the establishment and growth harmful bacteria are inhibited; For TSP-X use 75oF @ 80% RH (relative humidity) for 48 hours!

Biochemical reactions occur between the salt and the muscle proteins. The curing reactions are quite complicated and require some knowledge of biochemistry. The important thing to understand is that it is the salt and the curing salts that are responsible for curing the meat. The salt concentration should never be reduced in order to limit your intake of sodium.  Besides curing the meat, salt and cure  are necessary to kill any pathogenic bacteria and trichina worms that may be in the ground muscle meats. Generally, the concentration of salt is 2.5-3.5% of the weight of the ground meat before any ingredients are added. The aging or maturation process is strictly defined by the USDA, and the reader is directed to review this document. I can't overemphasize the importance of keeping notes on the entire process in order to aid in the evaluation the final product.

II. The Incubation Phase: It is during this phase that the amateur salami maker becomes somewhat concerned because of the unanticipated "foul" odors that begin to emanate from the incubation chamber.  Some of the odor is generated by the enzymes in meat and digestive activities of the microorganisms that cause glycolysis, proteolysis, lipolysis and lipid oxidation. These chemical and enzymatic reactions during dry sausage fermentation process degrade proteins into peptides, dipeptides and amino acids, and lipids into fatty acids. Amino acids are further degraded into amines and other aroma compounds. The fatty acids are oxidized into aromatic aldehydes, alkanes, alcohols and ketones. These compounds and orders are normal and are the result of bacterial fermentation that are breaking down their food sources in the meat...I assure you that the finished product will not taste as now smells. These odors disappear during the aging process as the salami matures.

The stuffed salami is incubated at 70°F - 110°F from 1 to 2 days...again depending upon the the starter culture used. The relative humidity is generally kept at 75%-85% (although some formulations require as high as 90% R/H). During this phse there is a rapid growth of Lactic Acid Bacteria producing copious quantities of lactic acid.  The presence of this acid and the salt in the wet meat inhibits the growth of harmful microorganisms such as Escherichia coli  (E. coli), Listeria monocytogenes, Salmonella species. In addition the growth of both Bacillus sp. and Clostridium sp. spores which may be introduced to the meat paste from spices that are used to flavor the salami are also inhibited at thiis time.

In contrast to the LAB used as starter cultures, staphylococci are able to improve the flavor of meat products because of the proteolytic and lipolytic activity of their enzymes. The Staphylococci  are important in fermentation because of two major enzymes (nitrate reductase and catalase) they produce Nitrate reductase is important for the promotion of color by breaking down nitrate to nitrite to nitrous oxide. This is essential for good color development in the meat.

Other bacteria present in the meat paste produce hydrogen peroxide (H2O2), which will cause poor color development and fat rancidity. The catalase enzyme produced by the Staphylococci breaks down hydrogen peroxide to harmless oxygen and water

Any storage container that can maintain a consistent temperature and humidity and provide some air flow can be used as an incubation chamber. I use an old, non-functional freezer cabinet that I modified and set the thermostat on a heater unit to maintain 70°F; I also added a baby nursery humidifier and adjusted air flow to maintain 85-90% R/H. This temperature and humidity is ideal for bacterial growth.

As i keep emphasizing, the salami maker must use all possible means to favor the beneficial and hinder the spoilage bacteria by using a lactic acid bacteria starter culture. As you can imagine, the ground meats contain a whole host of bacteria; some beneficial, others harmful. I mentioned that harmful bacteria like Clostridium botulinum, which produces a toxin that causes botulism in humans can be possibly present as spores in the ground meat.  Sodium nitrite is added to dry cured salami in order to kill this organism, therefore it is an essential ingredient in the amounts regulated by USDA; too little and it won't control botulism; too much and it may kill you! Lactobacilli in starter cultures ferment the sugars in the paste, producing lactic acid, among other things. This has be shown to successfully hinder the growth of harmful bacteria by lowering the pH (increasing the acidity) of the meats.

III. The Drying Phase: After incubation, the salami are dried in order to lower the water content of the meat. At the conclusion of this drying phase,  the salami can be held without refrigeration. The drying may lasts 30 days or more depending upon the diameter of the salami. Large diameter salami, stuffed in beef bungs may require 65 days! During this phase the salami will loose between 35% to 45% of its water. The reduced availability of water prevents growth of spoilage bacteria. The temperature during this phase is generally 55-65°F with a relative humidity of 70-80%.  The maintenance of this high humidity is necessary to prevent "case hardening". That occurs when the outer circumference of the salami dries faster than the interior preventing the diffusion of water from the interior to the environment. An excessive superficial drying can also cause the formation of interior cavities within the salami and a general loss of compactness of the meat and trapping oxygen which will lead to the formation of a rancid product.

The drying and aging conditions must provide an environment where the moisture transfer process can occur as consistently as possible in order to preserve the salami.  Moisture migration in a dry dry-cured sausage is a good example of the application of water activity. The driving force between the internal and external water vapor produces a water flow which is known as osmotic dehydration.  For completeness purpose a brief discussion of water activity is included. This measurement  is essential for commercial processors as well as for research purposes. While important for a commercial production facility  it is beyond the scope of the hobby salami maker due to the high cost of accurate instrumentation which produces reproducible results.

The water activity of dry-cured meats is a very important aspect of their preservation. The major application of water activity measurement concerns the control of microbial growth. While the mathematical expression is simply stated, it's experimental  measurement is not!  Water activity (Aw) is the ratio of the water vapor pressure (WVP) in  the salami to the water vapor pressure of pure water.

Aw = WVP product /WVP pure water

Most pathogenic bacteria in food can be stopped by water activity of around Aw 0.90. The growth of microorganisms stops at this level simply because there is insufficient free water available to to them to carry on their vital chemical reactions.  

During this time, the casing of the salami will mold. This is natural and it imparts complexity to the flavor of the salami. If this is objectionable to you,  rub the salami (when completely mature)  with a cloth to partially remove the mold and dust it with rice flour.
 

A word about “salami mold: Old world style salami are generally covered with a fine white mold.  This is considered extremely desirable characteristic in both European and San Francisco style dry-cured products.  See Salami War. There are two major groups of micro-organisms that contribute to this bloom: Yeasts and Molds. The very first organisms to appear after fermentation are single celled yeasts.  They form a slightly "sticky" film over the surface of the casing. The most common found on Italian-style salami is several species of Debaryomyces hansenii,  A few days after the growth of yeast, assuming the temperature and humidity of the recipe is adhered to, the appearance of a fine white mold begins to grow, supplanting the yeast cells. This mold will grow and mature over the coarse of the aging period. Is is edible...I can only say that if grown on natural casings, I've eaten it with absolutely no ill effects.  Its up to you to decide! Fungal species of the genus Penicillium are a frequently used as commercial starter cultures for mold ripened foods, especially cheeses. Penicillium roqueforti, for example, is used in cheese to develop characteristic blue veins such as in Roquefort Blue, Danish Blue, Gorgonzola, Stilton and other blue style cheeses. It is common practice to use mold starters for salami-type products, especially in Europe….after stuffing, the salami casings are sprayed or dipped in the mold culture before they are sent off for fermentation.  Three species of these fungi, P. notatum, Penicillium nalgiovense and Penicillium chrysogenum have been isolated from both European and U.S. dry-cured salami.  These molds help in flavor development by decomposing excess lactic acid and inhibiting the growth of other undesirable molds. P. notatum was the first species of fungus that is used to commercially produce the antibiotic penicillin. From the physiologic, as well as the genetic, point of view Penicillium notatum seems to be related very closely to Penicillium chrysogenum and Penicillium nalgiovense since these also both producers of the a-lactam antibiotic penicillin; all three contain the same gene sequence necessary for biosynthesis of penicillin. Starter cultures of these organisms are now available in small quantities here in the U.S. You can purchase them from Butcher-Packer Company. See Resources page for the link. The one I use is shown at the right.

Note: Hansen has changed M-EK-4 designation to:
 Mold - 600 Bactoferm (TM) Sausage Mould

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