🥩 Curing, Smoking and Drying

Curing is not magic and it is not tradition. It is arithmetic against a table of bacterial growth limits. Every bacterium that can hurt you has a minimum temperature, a minimum pH, a minimum water activity and a maximum salt concentration below or above which it cannot multiply. Preservation means pushing your product past one of those limits and keeping it there.

A small butchery has three barriers.

1. Salt. It raises osmotic pressure and lowers water activity, which is the amount of water in the product that bacteria can actually use.
2. Nitrite and nitrate. These specifically inhibit Clostridium botulinum, fix the cured pink colour, contribute cured flavour and retard rancidity.
3. Drying. This lowers water activity directly by removing water.

Smoking is often listed as a fourth, but it belongs in a different category and Lesson 4 deals with it separately. Hot smoking cooks; cold smoking does not preserve on its own.

Now look at what the barriers are aimed at. From the published master table of growth limits:

• Clostridium botulinum, proteolytic types A and B and F: minimum 10 degrees Celsius, minimum pH 4.6, minimum water activity 0.935, tolerates up to 10 percent salt. It is a strict anaerobe.
• Clostridium botulinum, non-proteolytic type E and B and F: minimum 3.3 degrees Celsius, minimum pH 5.0, minimum water activity 0.97, tolerates up to 5 percent salt. This one grows at refrigeration temperature.
• Listeria monocytogenes: minimum minus 0.4 degrees Celsius, tolerates 10 percent salt, water activity down to 0.92.
• Salmonella: minimum 5.2 degrees Celsius, minimum water activity 0.94, up to 8 percent salt.
• Staphylococcus aureus: grows from 7 to 50 degrees Celsius, water activity down to 0.83, in up to 20 percent salt.

Read the last line again. Staphylococcus aureus grows in 20 percent salt and down to water activity 0.83. Salt does not stop it. Drying does not stop it. It is the pathogen that beats curing, and it is the one you must understand before you cure anything.

S. aureus comes from people. It lives in the nose, on the skin, on hands and especially in infected cuts, boils and sores. It also comes from the udder of animals. It does not compete well, so it thrives exactly where competitors have been killed or inhibited: on cooked product, on heavily salted product, on product handled by hand. In other words, on cured meat.

And it produces a heat-stable toxin. Toxin production needs a slightly narrower range than growth: 10 to 48 degrees Celsius, water activity 0.85 or above, and up to 10 percent salt. But once that toxin is formed, cooking does not destroy it. There is no recovery from a Staphylococcus aureus failure. You cannot cook it out, you cannot dry it out, and you cannot sell your way out of it.

The controls that work against it are all about people and about speed. Exclude any staff member with a skin lesion, boil or infected cut from handling meat. Cover any minor wound with a waterproof, brightly coloured dressing, conventionally blue so that a lost dressing is visible against meat. Wash hands. Minimise hand contact with cooked and cured product. And hold product outside the 10 to 48 degree band so toxin is never formed, which in a curing process means getting through the wet, warm phase fast.

The second thing curing does not do is fix bad meat. Curing is a barrier against growth, not a lethal step. Salmonella can survive several weeks in a dry environment: drying does not kill it, it only stops it multiplying. So a cured or dried product is only as safe as the raw material and the hygiene that went into it. Meat that was contaminated at slaughter stays contaminated through the salt.

Third, curing does not suspend meat quality rules. Dark, firm and dry meat, with a post-rigor pH above 5.9, must not be selected for curing. Its high pH supports microbial growth, its shelf life is already reduced, and it is exactly the wrong starting point for a slow process.

So the honest description of curing is this: a set of barriers that stop the growth of most organisms, that specifically inhibit the deadliest one when nitrite is used lawfully, that do nothing at all about a toxin formed by a human-carried organism before the barriers took effect, and that cannot repair a hygiene failure that happened before you started. Everything in the rest of this module follows from that.

The practical consequence for your business is that curing raises your standard, it does not lower it. A butchery that cannot hold a chiller temperature, cannot keep records and cannot keep staff with infected cuts away from meat should be selling fresh, fast-turning product, not building a curing room.

This is the most legally dangerous lesson in the course, and the one where this course will give you the least. Read why before you read anything else.

Nitrite limits are national law. They vary between countries, they are legally binding, and nitrite is acutely toxic at a modest overdose. This is not a matter of best practice. It is a matter of law and of poisoning a customer. This lesson will show you two countries' rules as worked examples of how such a rule is written. Neither of them is your rule. Almost certainly, neither is even close to your rule. Before you add nitrite to any product for sale, you must obtain the current permitted maximum from your national food-safety authority, food control agency or standards bureau, from the food additives regulation itself, not from a summary, not from a forum, and not from this course.

First, what nitrite does. It inhibits Clostridium botulinum, and that is its primary safety function. In nitrite-cured products the presence of the nitrite should ensure compliance with the performance standard for C. botulinum. It fixes the cured pink colour by forming nitrosylmyoglobin and, after cooking, nitrosomyochromogen. It contributes cured flavour. And it retards rancidity. Remove the nitrite and you have not simply made a paler sausage: you have removed the barrier against the most dangerous organism in meat processing.

Now the worked examples, presented as illustrations of how a competent authority writes a rule.

In the United States, university extension and the code of federal regulations report combined nitrite and nitrate ingoing limits of not greater than 156 parts per million for hams and not greater than 120 parts per million for bellies, that is bacon. Dry cure figures are given as 1.0 ounce of sodium or potassium nitrite per 100 pounds of meat, and 3.5 ounces of nitrate. A liquid pickle cure at 10 percent pump is given as 2.0 pounds of nitrite per 100 gallons and 7.0 pounds of nitrate. For pumped or massaged bacon the figure is 120 parts per million ingoing sodium nitrite, or 148 parts per million potassium nitrite, with sodium ascorbate or erythorbate at 550 parts per million. Immersion-cured bacon is not to exceed 120 parts per million ingoing sodium nitrite. Dry-cured bacon is not to exceed 200 parts per million sodium nitrite, or 246 potassium. Reduced-nitrite bacon formulations are described at 100 parts per million sodium nitrite, or at 40 to 80 parts per million with added carbohydrate and lactic acid bacteria.

Two pieces of the United States picture could not be verified for this course: the maximum residual nitrite permitted in finished product, and the full curing table for comminuted and immersion-cured products. If you need them, obtain 9 CFR 424.21(c) in full from the eCFR.

In the European Union, a regulation applicable from 9 October 2025 sets a maximum for general meat products of 80 milligrams per kilogram expressed as nitrite ion, down from 120 expressed as sodium nitrite, and for sterilised meat products 55 milligrams per kilogram, down from 82. Residual levels are set at 25, 45 or 50 milligrams per kilogram depending on product type. The new EU maximum levels for nitrates could not be verified and must be obtained from the regulation itself via EUR-Lex.

Inside that EU example sits a trap that will catch you in any jurisdiction. The EU moved from expressing limits as sodium nitrite to expressing them as the nitrite ion, with conversion factors of 0.67 for nitrites and 0.73 for nitrates. So a figure of 120 and a figure of 80 can describe the same amount of chemical. Whenever you read a nitrite limit, the first question is not what is the number, it is what basis is the number expressed on: nitrite ion, sodium nitrite, or combined nitrite and nitrate. A butcher who reads the number and ignores the basis can overdose a product by half again while believing he is compliant.

Four handling rules apply regardless of jurisdiction, and none of them is optional.

1. Never buy or use loose, unlabelled curing salt. Use a commercially formulated cure with a stated nitrite percentage and a stated usage rate on the packaging.
2. Never store nitrite or a nitrite premix in an unlabelled container, and never beside ordinary salt. The two look identical and the mistake is fatal.
3. Weigh cure on a scale accurate to the gram. Never measure by volume, by scoop or by eye. An indicative gram scale costs 50 to 200 USD, unverified, and it is the cheapest insurance in the building.
4. Keep cure locked away from general staff access.

Add a fifth for your records: the weight of cure recorded against the weight of meat, every single batch, signed and dated. That record is the only evidence you will have if a product is ever questioned, and it is the thing that will show you a weighing error before a customer does.

If you cannot obtain your national limit, the correct professional response is to make the product uncured, sell it fresh with a short shelf life, and revisit the decision when you have the regulation in your hand.

Water activity is the single most useful idea in meat preservation, and most butchers have never heard of it. It is not the same thing as moisture content. It is the proportion of the water in a product that is free for bacteria to use. Salt and sugar bind water; drying removes it. Both lower water activity, and bacteria respond to water activity, not to how wet something feels.

The scale runs from 0 to 1.0, where pure water is 1.0. The published thresholds are these:

• At water activity 0.95, a certain number of micro-organisms are inhibited.
• At 0.92, all bacteria groups are inhibited, but moulds and yeasts can still grow.
• 0.91 is the minimum permitting growth of normal spoilage bacteria.
• 0.88 is the minimum for yeasts.
• 0.80 is the minimum for moulds.
• 0.77 is the minimum for halophilic, that is salt-loving, bacteria.
• Below 0.85 is a regulatory requirement for shelf stability in the United States, quoted here as an example of how a regulator sets such a threshold.

Set those against the pathogens. Salmonella stops at 0.94. Pathogenic E. coli including O157:H7 stops at 0.95. Listeria stops at 0.92. Proteolytic C. botulinum stops at 0.935 and the non-proteolytic type at 0.97. And Staphylococcus aureus grows down to 0.83 and produces toxin down to 0.85. So a product dried to 0.90 has stopped Salmonella, E. coli, Listeria and both botulinum groups, and has not stopped S. aureus. That is the whole reason Lesson 1 spent so long on staff health and hand contact.

Typical water activity of product classes, published:

• Dried meat, including biltong and charque: 0.75 to 0.50.
• Dry sausage of the salami type: 0.96 to 0.70.
• Raw cured ham: 0.96 to 0.80.
• Commercial jerky as observed in the market: about 0.77 to 0.87, with most premium brands between 0.78 and 0.84.

Notice that a dry sausage and a raw ham can both sit at 0.96, which is above every pathogen threshold except the non-proteolytic botulinum limit. Those products are not safe because they are dry. They are safe because of the combination of salt, nitrite, acidity and time. Drying alone is not a preservation system.

Now salt. The published concentrations are these. In cooked cured products, salt should not exceed 2.5 to 3 percent. In raw cured and dried products, it should not exceed 4.5 to 5 percent. Brines, that is pickles, are in use at 8 to 22 percent sodium chloride. And the general curing target in the product itself is described as about two to three percent being right.

Read those as they are written: the 2.5 to 3 and the 4.5 to 5 figures are ceilings on what the product should carry, not targets to aim above. Salt above those levels makes the product unpalatable long before it makes it meaningfully safer, and it accelerates fat rancidity, because salt is a pro-oxidant.

The brine range is wide, 8 to 22 percent, because a brine is not the product. The concentration in the brine, the time in the brine, the temperature and the thickness of the piece all decide how much salt ends up in the meat. This course does not have a sourced table converting brine strength and time into finished salt concentration, so do not build one from guesswork. Work from a cure supplier's stated usage rate, weigh your meat, weigh your cure, and verify the outcome by measuring.

Which brings us to the hard commercial truth of this lesson. Water activity cannot be judged by feel, by look, by weight loss or by experience. It is measured with a water activity meter, at an indicative and unverified 1,500 to 4,000 USD, and there is no substitute. If you are making a dried or shelf-stable product and you do not own a meter, you cannot demonstrate that the product reached a safe water activity. You can only hope. Hope is not a control point, and it is not a defence.

The honest conclusion, and this course states it plainly: if the meter is unaffordable, your butchery is not yet equipped to sell dried meat. That is a business decision about sequencing, not a judgement about your skill. Sell fresh, cooked and chilled product, build the turnover, and buy the meter when it is affordable.

One more practical point. Weight loss during drying is a useful process indicator and you should record it, because it tells you whether this batch behaved like the last one. It is not a safety measurement. Two batches can lose the same percentage of weight and end at different water activities, depending on the salt they carry, the fat content, the piece size and the humidity of the room. Record weight loss to control your process; measure water activity to prove your product.

Smoking does three things: it puts flavour on the meat, it dries the surface, and its compounds have some antimicrobial and antioxidant effect. What it does not reliably do, by itself, is make a product safe. Whether smoking contributes to safety depends entirely on the temperature at which you do it, and that is the difference between hot and cold smoking.

Hot smoking applies smoke while cooking the product. It includes a lethal step, because the product reaches a temperature that kills vegetative bacteria. Cold smoking applies smoke below cooking temperature. It provides no lethal step at all. A cold-smoked product relies entirely on salt, nitrite and drying for its safety, and this course will not teach cold smoking as a preservation method in its own right. If you cold smoke, everything that makes the product safe happened in the curing and drying, not in the smokehouse.

The published temperature stages for smoking emulsion-type products in a small or medium plant run like this:

1. Tempering before smoking, to dry the surface: 1 to 2 hours at room temperature. Smoke does not deposit evenly on a wet surface, so this step is about product quality and appearance.
2. Smoking start temperature: approximately 43 to 55 degrees Celsius.
3. Mid-phase: 65 degrees Celsius.
4. Final heavy smoking: 70 to 75 degrees Celsius.
5. Terminal smoking: 80 to 85 degrees Celsius.
6. Relative humidity during smoking: about 80 percent.
7. Duration for bologna or mortadella: 6 to 8 hours.

The stages exist because you are doing several things in sequence: drying the surface, depositing smoke, setting the colour and cooking the product. Going straight to the top temperature case-hardens the surface, seals it, and stops both smoke penetration and moisture loss.

Now the safety line, and it is the same one as in Module 9. The temperature you must hit is the internal temperature of the product, and this course teaches 71 degrees Celsius for minced and emulsion products and 74 degrees Celsius for poultry products. Smokehouse air temperature is not product temperature. A smokehouse running at 80 degrees does not mean the sausage inside it is at 80 degrees, and the only way to know is a calibrated probe in the thickest part of the thickest piece in the load, in the coldest part of the chamber.

That last phrase matters. Every smokehouse has cold spots: near the door, on the bottom rail, behind an overloaded rack. Find yours by probing several pieces from different positions, and then always monitor the position that runs coldest. If you monitor the hottest spot you are recording a number that proves nothing.

The published cooking figures that accompany smoking of emulsion products are a cooking vat water temperature of 73 to 76 degrees Celsius, a water spray at 80 to 82 degrees, and a total smoking and cooking cycle of one to two hours as an optimum, extended to two or three. The published internal end-points of 65 degrees as a minimum and 68 degrees as an optimum are lower than the 71 and 74 degree figures this course teaches, and the reason is important: lower temperatures held for longer can achieve the same lethality, but only against a validated time and temperature lethality table. No such table was available for this course. Until you obtain one, specifically the USDA FSIS Appendix A compliance guideline on lethality performance standards or your national equivalent, use 71 and 74.

What happens after the smokehouse is a control point in its own right, and it is the one small producers most often miss. A cooked product cooling slowly is the perfect environment for Clostridium perfringens, whose spores survive cooking and whose growth range is 10 to 52 degrees Celsius in anaerobic conditions, which describes the interior of a cooked sausage exactly. The published stabilization rule is that product must not remain between 54 and 27 degrees Celsius for more than 1.5 hours, and must not remain between 27 and 4 degrees Celsius for more than 5 hours, achieving no more than one log of total growth. An older option begins chilling within 90 minutes of cooking and goes from 48 to 12.7 degrees Celsius in no more than 6 hours. For nitrite-cured products a slower option is permitted: 54 to 27 degrees in 5 hours and 27 to 7 degrees in 10 hours, 15 hours in total.

Hanging hot product on a rack in a warm room overnight breaks every one of those options. Chill deliberately: cold water spray, a blast of cold air, smaller pieces, spread out rather than stacked, and a thermometer with the times written down.

Two more practical points. First, wood matters for flavour and for what it deposits, and treated, painted or resinous wood must never be used. Second, a smokehouse is a piece of equipment with a fire in it, in a building full of fat. Grease accumulation in the chamber and the flue is a genuine fire risk, and cleaning it is not optional maintenance.

Finally, remember what smoking cannot do. It cannot rescue meat that was contaminated before it went in, it does not destroy Staphylococcus aureus toxin, and light smoking reduces mould growth on cured product surfaces without sterilising anything. Smoke is a finish, not a repair.

Biltong is the culturally dominant dried-meat product across southern Africa and a genuine commercial opportunity. It is also the single largest safety gap in this course, and this lesson is going to tell you plainly what is not known rather than fill the gap with something that sounds authoritative.

Start with what biltong is, technically. It is a raw, non-heat-treated meat product. There is no cooking step. Nothing in the process kills bacteria by heat. Its safety rests entirely on the combination of marinade, salt, acid, usually vinegar, and drying. That combination has to do all the work that a cooking step does in every other product in this course.

Now the facts that are sourced. Dried meat, including biltong and charque, typically sits at a water activity of 0.75 to 0.50. A water activity below 0.85 is a regulatory requirement for shelf stability in the United States, quoted as an example of how such a threshold is written. Commercial jerky observed in the market ran about 0.77 to 0.87, with most premium brands between 0.78 and 0.84. Those are the endpoint targets, and they are legitimate teaching.

Here is what is not known, and it is the heart of the matter. The specific marinade composition, salt level, vinegar concentration, drying air temperature, air velocity, drying time and final water activity that have been validated to achieve a pathogen log-reduction in biltong were not available for this course as a complete parameter set. That means no recipe in this module, and no recipe you find in a magazine or from another butcher, can be called a validated process.

To obtain a validated process you need three things:

1. The University of Wisconsin Center for Meat Process Validation status summary on lethality attained in dried non-fermented beef products, which covers biltong and basturma.
2. Peer-reviewed biltong validation studies, including work on achieving a 5-log Salmonella reduction in biltong without a heat lethality step.
3. Your national food-safety authority's requirements for dried meat products, which are jurisdictional and which override everything else.

Until those are in your hand, teach and treat the endpoint, not the recipe.

Why this matters so much comes down to two organisms.

Salmonella can survive several weeks in a dry environment. Drying does not kill it. It stops it multiplying at a water activity of 0.94, but the cells that were on the meat when you hung it are still there when you take it down, and its infective dose can be as low as one cell depending on the strain and the health of the person eating it. If Salmonella went into the drying cabinet, it comes out.

Staphylococcus aureus grows down to a water activity of 0.83 and in up to 20 percent salt, and produces its heat-stable toxin down to 0.85. Look at what that means for the drying curve. Meat hung wet sits at a water activity near 1.0 and passes slowly down through 0.99, 0.95, 0.90, 0.85 on its way to 0.75. Every hour it spends above 0.85 in the 10 to 48 degree band is an hour in which S. aureus can form toxin, and once formed nothing you do afterwards removes it. That is why the wet phase of drying must be fast, and why hand contact with the wet meat must be minimal, and why staff with cuts, boils or sores must not be near it.

So the safety of a dried product depends on three things together:

• The raw material was hygienically produced and did not carry Salmonella or E. coli O157:H7 to begin with.
• It was salted and acidified promptly and dried fast enough that S. aureus never had time to form toxin in the wet phase.
• It reached and held a water activity you have measured, not estimated.

That third point is where most small biltong businesses fail. A water activity meter, at an indicative and unverified 1,500 to 4,000 USD, is the only way to monitor the endpoint. Weight loss is a process indicator, not a proof. Feel, snap, colour and experience prove nothing. Without a meter you cannot demonstrate anything about the product you are selling.

The blunt sentence this course insists on: a biltong process that has always worked is not a validated process. It is an untested process that has not yet failed in a way you noticed. Small numbers of illnesses are rarely traced back to a single small producer, so the absence of complaints is very weak evidence.

What you should do, in order:

1. Obtain your national requirements for dried meat products. Start there, because they may prohibit or restrict what you were planning.
2. Obtain the validation literature named above.
3. Buy or arrange access to a water activity meter before you sell, not after.
4. Fix your hygiene, staff health rules and raw material sourcing first, because the drying step will not fix them for you.
5. Record for every batch: the meat source, the weight in, the salt and marinade weights, the times, the drying conditions, the weight out and the measured water activity.

Surface browning that is excessive on dried product comes from the Maillard reaction, which optimises at a water activity of 0.65 to 0.75, so it is a drying-rate and surface-humidity issue, not a sign of doneness. Judge nothing by colour.

None of this says do not make biltong. It says make it with the documents, the meter and the records, or make something else until you have them.

This lesson exists because the honest answer for many small butcheries is not yet, and nobody in the supply chain has a commercial interest in telling you that. Cure suppliers sell cure. Equipment dealers sell drying cabinets. Trainers sell courses. This course sells you the ability to make the decision properly.

Work through six preconditions. Every one is a gate. If you cannot pass a gate, you do not proceed past it.

Gate one: the law. Do you have, in your hand, the current text of your national regulation setting nitrite and nitrate limits, from your national food-safety authority, food control agency or standards bureau? Do you know which basis the limit is expressed on, nitrite ion or sodium nitrite? Do you know whether there is a residual limit as well as an ingoing limit? If you are making dried products, do you have your national requirements for dried meat products? If the answer to any of these is no, you cannot lawfully cure for sale. This is not a technicality. Nitrite is acutely toxic at modest overdose and the limits are legally binding.

Gate two: the raw material. Curing is a barrier against growth, not a lethal step. It cannot repair a hygiene failure. Can you demonstrate that your meat arrives from a hygienic slaughter and is held at your national chilled storage temperature throughout? Do you keep goods-inwards records with measured arrival temperatures? Can you keep DFD meat, with pH above 5.9, out of the curing stream? If you cannot, curing simply preserves your problem for longer.

Gate three: the people. Staphylococcus aureus is the pathogen of the food handler, it beats salt and drying, and its toxin survives cooking. Do you exclude staff with diarrhoea or vomiting, and staff with infected cuts, boils or skin lesions, from handling meat? Are wounds covered with waterproof blue dressings? Is hand washing actually done, with liquid soap and paper towels at a basin that is not hand-operated? Is money handled by a separate person or with a hand wash between? These are the cheapest controls in the building and the ones that matter most for cured product.

Gate four: the measuring equipment. A curing operation is unmonitorable without three things: at least two calibrated probe thermometers, indicative 20 to 80 USD; a scale accurate to the gram for cure, indicative 50 to 200 USD; and, for any dried or shelf-stable product, a water activity meter, indicative 1,500 to 4,000 USD. All figures are unverified and require three local quotations. The first two are trivial in cost against a condemned batch. The third is the real gate on dried meat as a business, and there is no substitute for it.

Gate five: the records. Curing generates more records than fresh trading, not fewer. Weight of cure recorded against weight of meat, every batch. Water activity for every dried batch. Cooking and cooling temperatures with times. Chilled storage temperatures at least twice daily, with one check before production starts. Cleaning records. Staff health declarations. Water test certificates. Thermometer calibration records, and note that the required calibration frequency and method could not be verified for this course, so obtain them from your national food-safety authority and the thermometer manufacturer. All records signed, dated and kept. And made at the time: a record written up afterwards destroys the credibility of every genuine record beside it.

Gate six: the money. Cured products carry higher margins, and they also carry longer holding times, more capital tied up in stock, higher energy costs and a real risk of losing a whole batch. Run the arithmetic in the same way as Module 9 taught for sausage. Cost your lean at your true cost per kilogram of saleable meat, not at the live purchase price. Weigh your process yield yourself, because drying loss is enormous and no sourced figure for your product exists here. Add labour, energy, packaging, cleaning, depreciation and wastage, remembering that a 10 percent wastage rate raises the effective cost per kilogram by roughly 11 percent. Then compare the result to what your market actually pays, which you measure by surveying, not by assuming.

There are three legitimate outcomes and none of them is a failure.

Proceed. You pass all six gates. Write the process down, monitor it, keep the records, and start with one product rather than four.

Defer. You pass most gates but not the equipment or the legal one. Write down exactly which gate failed, what you need to pass it, and when you will revisit. Meanwhile sell fresh, cooked and chilled product. A fresh sausage sold the day it is made is a lower-risk, faster-turning business than biltong, and it builds the turnover that buys the meter.

Decline. Some products should not be made in some premises, and cold-smoked or vacuum-packed long-shelf-life products are the clearest case. A moist, low-acid, low-salt product held under vacuum for weeks is exactly what non-proteolytic C. botulinum, which grows from 3.3 degrees Celsius, needs. Note also that the toxin dose and the heat resistance of botulinum spores and toxin could not be verified for this course, so no time or temperature for destroying them is given anywhere in it. If you need those figures, obtain the FDA Bad Bug Book, second edition, chapter on Clostridium botulinum, and your national guidance on shelf-stable and reduced-oxygen packaged products. Do not accept any botulinum time or temperature from memory, from a video, or from a supplier.

Write your decision on one page, sign it, date it, and keep it. It is the document that shows an inspector or a hotel buyer that you understand your own process, and it is worth more to your business than any recipe.