Meat processing
Processed meat products are a broadly composed group ranging from whole muscle products such as cured pork loin, cured veal or marinated chicken portions to comminuted products, for example sausages, and from uncooked products to canned meats. Common for them all is that they have been exposed to a process.
The processed meat products comprise cold cuts, sausages, canned products etc.
Raw materials
The raw materials for the processed products come from all parts of the carcass. For the expensive products, whole meat pieces are normally used; this is for example the case for bacon, cooked ham, cured pork loin and smoked loin. The processing is often curing and possibly smoking and heat treatment.
Comminuted meat products are made from chopped/minced raw materials. The raw materials are often smaller meat and fat pieces, which are cut off during trimming and boning of the cuts. The less valuable parts of the carcass, for example jowls and shank muscles, are also often used for comminuted products.
During the comminution of the meat, various ingredients are added; for example salt, phosphates, proteins, starch and spices. The meat mixture is used for making sausages and canned meat products, for example luncheon meat (a typical export product).
Curing
During curing, sodium chloride (NaCl) is added, often together with water, nitrite salt (i.e. salt with 0.6% sodium nitrite), phosphates, ascorbate etc.
The curing has several purposes: To provide flavour and juiciness and to improve the shelf-life.
The salty flavour is important for the correct taste of the products. Investigations have shown that approximately 2% salt is suitable for the majority of modern consumers. Many products were more salty earlier, but the focus in recent years on the unfortunate effect of salt on the blood pressure has contributed to a reduction of the salt content.
Curing is an old method for food preservation. The salt inhibits the growth of many bacteria and stops some of the enzymes in the meat that contribute to its breakdown. In modern meat products the salt content is, however, so low that the shelf-life is prolonged through refrigeration, packaging etc.
Smoking
Smoking is an old traditional preservation method. Smoking will preserve the surface of the product by inhibiting the growth of the bacteria. In addition a drying can occur; this will also contribute to a longer shelf-life. Finally the smoke provides colour and flavour - this is today the main reason for the smoking of meat products.
Smoking can be done in three ways depending on the temperature and time for the smoking:
Cold smoking, where the temperature is 20-30oC, i.e. where the smoke is cooled. Cold smoking is for example used for salami sausages. Cold smoking is often done over an extended time period from some days to several weeks.
Semi-warm smoking, where the smoke temperature is ca. 40oC. This smoking method is used for bacon, cured pork loin and various cold cuts.
Hot smoking, where the products are heated to 70-90oC; the products are therefore cooked and can be eaten without further heat treatment. The process typically consists of drying, smoking and cooking. Hot smoking is for example used for
Heat treatment
Many processed meat products are heat treated (cooked) as part of the process. Most cold cuts receive a mild heat treatment equal to pasteurisation, i.e. a heating to a core temperature of at least 75oC. Depending on the packaging method, on whether the products are sliced or sold as a piece, on the storage temperature (maximum 5oC) etc., the typical shelf-life ranges from some weeks to a couple of months.
Perishable canned meats are products that are cooked in an impermeable pack and have a shelf-life of at least six months when refrigerated. When the pack is opened, the shelf-life is only a few days or weeks under refrigeration.
Fully stable canned meats are products that are heat treated to have a shelf-life of at least one year at room temperature - in practice often considerably more. Heat treatment is done in an autoclave (an industrial 'pressure cooker'), where the core temperature in the products reaches 120-122oC. Canned meats are nearly always packed in metal cans.
Additives
Various additives are used for processed meat products. Statutory regulations determine the permitted types and quantities of additives for each product.
Preservatives are used to increase the shelf-life. For meat it is mainly nitrite, which inhibits the growth of bacteria. Nitrite is used as nitrite salt; a mixture of salt and 0.6% sodium nitrite.
Emulsifiers, stabilisers and thickening agents. Emulsifiers are compounds that make it possible to produce a stabile mixture of fat and water that does nor separate. Some proteins, e.g. soy and milk proteins, are used in comminuted products to prevent fat separation during cooking. Polyphosphates also have an emulsifying effect. Stabilisers and thickening agents bind water and contribute to a firm texture of the products.
Colouring matters are only used in certain products, i.e. salami, Saveloy sausage and hot dog sausages ('red sausages'). The similar products without added colour are 'spegepølse' (South Jutland salami), kødpølse ('meat sausage') and
Various are compounds that do not come in the other groups of additives. This includes flavour enhancers, e.g. 'the third spice' (mono sodium glutaminate) that enhances the flavour of meat products without itself having any taste. Other compounds are glucona-delta-lactone, which is used to regulate the acidity (pH) and ascorbic acid (vitamin C), which for example stabilises the colour in meat products.
