MEAT TECHNOLOGY: PRESERVATION OF MEAT
Diagram
Two ways to preserve meat
Curing
Salt, and usually nitrite or nitrate, is rubbed into the meat or dissolved in a brine. The salt draws out water and the nitrite gives cured colour and flavour and stops the growth of spoilage bacteria.
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Smoking
The meat is hung in smoke from burning wood. The smoke dries the surface, adds flavour and colour, and deposits compounds that slow bacteria.
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Often together
Many products are cured first and then smoked: ham, bacon and smoked sausage use both steps, one after the other.
Figure 1: Curing works with salt and nitrite inside the meat; smoking works with wood smoke on the surface. Drawn in our own style from the Curing chapter (p. 46) and Smoking chapter (p. 69) of Pearson and Tauber, Processed Meats.
Introduction
Smoking and curing are the two oldest ways of preserving meat, and they are often used together, which is why people mix them up. Curing is the treatment of meat with salt, usually with nitrite or nitrate, while smoking is the exposure of meat to smoke from burning wood. Pearson and Tauber define meat processing as all processes that alter fresh meat except simple grinding, cutting and mixing, and that definition covers curing, smoking, canning, cooking, freezing and dehydration.
The core difference is what does the preserving: in curing it is the salt and nitrite working inside the meat, and in smoking it is the heat, drying and smoke compounds acting mainly on the surface. A ham is cured, a smoked salmon is smoked, and a smoked ham is both.
Quick comparison
Table 1: Smoking compared with Curing
| Aspect | Smoking | Curing |
|---|---|---|
| Preserving agent | Wood smoke, heat and drying | Salt, with nitrite or nitrate |
| Where it acts | Mainly on the surface of the meat | Right through the meat, as the cure spreads inward |
| Main effect on water | Dries the surface and lowers surface moisture | Draws water out of the meat and binds it, lowering water activity |
| Colour change | Golden brown surface colour from the smoke | Pink cured colour through the meat, from nitrite |
| Flavour | Smoky flavour from the wood | Salty flavour with the characteristic cured taste |
| Effect on microbes | Smoke compounds and drying slow bacteria on the surface | Salt and nitrite stop the growth of spoilage and harmful bacteria through the meat |
| Needs heat | Hot smoking uses heat; cold smoking uses little heat | No heat is needed for the cure itself |
| Typical products | Smoked fish, smoked sausage, smoked ham | Ham, bacon, corned beef, salami |
| Shelf life | Adds shelf life, but smoked meat alone may still need chilling | Adds shelf life by salt and nitrite; many cured meats keep without chilling when dried as well |
| Used alone or together | Often used after curing, rarely as the only step for meat | Often used before smoking, and works alone for products such as bacon |
Scientific explanation
Definition
Curing is the preservation of meat with salt, usually with nitrite or nitrate added. Pearson and Tauber give curing its own chapter (p. 46), and list the curing agents as sodium chloride, nitrite, ascorbate or erythorbate, and possibly sodium phosphate, sucrose, dextrose or corn syrup and seasonings. Smoking is the exposure of meat to smoke from burning wood, covered in its own chapter (p. 69).
The two are separate processes with separate chapters, but the book also has a chapter on cured and/or smoked meats (p. 270), because in practice a product is often cured first and smoked second.
Working principle
Curing works because salt draws water out of the meat and lowers its water activity, so bacteria cannot grow easily, and nitrite gives the pink cured colour and flavour and helps stop harmful bacteria. The cure spreads slowly from the surface into the middle of the meat, which is why large pieces need time.
Smoking works in three ways at once: the heat dries the surface, the smoke deposits flavour compounds and compounds that slow bacteria, and the drying lowers the moisture that bacteria need. Hot smoking also cooks the meat, while cold smoking flavours it without cooking.
Apparatus
Curing needs a curing vat or tank for brine curing, or a table for dry rubbing, and a cool room where the meat rests while the cure spreads. Smoking needs a smokehouse or smoke chamber with a firebox for the wood, racks to hang the meat, and a way to control temperature and air flow. The books used here describe the processes rather than naming one standard instrument for either.
Measurement procedure
For curing, the salt and nitrite mix is rubbed into the meat or dissolved in water as a brine, the meat is covered with it, and it is held cool until the cure has spread through. For smoking, the meat, usually already cured, is hung in the smokehouse and exposed to wood smoke for the time the product needs, with the temperature held at the level for hot or cold smoking.
The books used here give the principles and the chapters for both methods, but they do not give one single standard recipe or time for all products: times and amounts change with the size of the piece and the product being made.
Factors affecting readings
The size and thickness of the meat matter: a thick ham takes far longer to cure through than a thin strip of bacon. Temperature matters too: curing is done cool so bacteria do not grow while the cure spreads, and smoking temperature decides whether the meat cooks. The kind of wood changes the flavour of smoked meat, and the amount of salt and nitrite changes both the safety and the saltiness of cured meat.
Formulas and calculations
The books used for this article give no formula for this comparison, so none is given here. The comparison is qualitative: it rests on definitions, materials and method, not on a calculation.
Industrial applications
- Curing is used for ham and bacon, where salt and nitrite give the pink colour and the long shelf life.
- Curing is used for salami and other fermented sausages, where salt works together with fermentation.
- Smoking is used for smoked fish and smoked sausage, where the smoky flavour is the point of the product.
- Smoking is used after curing for smoked ham and smoked bacon, to add flavour and colour.
- Both are used in traditional meat plants to preserve meat without refrigeration, and in modern plants for flavour and shelf life.
Advantages and limitations
- Curing, advantage: preserves meat right through and gives the pink colour and flavour people expect in ham and bacon.
- Curing, limitation: makes the meat salty, and needs time for the cure to reach the middle of thick pieces.
- Smoking, advantage: adds a flavour no other method gives, and dries and protects the surface.
- Smoking, limitation: acts mainly on the surface, so on its own it does not preserve the inside of thick meat.
FAQ
Is smoked meat always cured first?
Often, but not always: many smoked hams and bacons are cured first and then smoked, but some smoked fish is only lightly salted and smoked. Curing and smoking are separate steps that are often combined.
Does smoking cook the meat?
Hot smoking cooks it, cold smoking does not. Cold smoked meat stays raw inside and still needs chilling, while hot smoked meat is cooked by the heat of the smoke.
What gives cured meat its pink colour?
Nitrite: it reacts in the meat to form the pink cured pigment. Meat without nitrite turns grey or brown when cooked, which is why uncured cooked meat looks different.
Can curing alone keep meat safe without a fridge?
It helps a great deal, but not on its own for every product: salt and nitrite slow bacteria, yet many cured meats still need chilling or drying to be safe for long storage.
Why does smoked meat taste smoky?
The smoke from burning wood deposits flavour compounds on the surface of the meat. The kind of wood changes the flavour, which is why different woods are chosen for different products.
