Nutritional significance
Meat processing
Suitability for small-scale production
Any animal can be used as a source of meat, ranging from the domesticated cow, pig, and chicken, to deer and camels.
The amount and type of meat eaten in a particular country is determined by factors such as cost, availability, and cultural or religious acceptability. In developing countries, meat is usually eaten fresh, and meat products, with the exception of dried meat in some African countries, are not commonly available or in significant demand.
Conditions under which animals are slaughtered in developing countries are often unhygienic, and animals may be slaughtered and displayed for sale in the open air without any covering. This enables bacteria to be transmitted by flies, other animals, and birds. Meat, like fish and milk, is a low-acid, moist food which provides a good environment for the growth of these bacteria. This may lead to rapid deterioration of the meat in tropical climates and fresh meat therefore has a very short shelf-life. Harmful micro-organisms may also grow on meat and produce food poisoning when eaten. This, together with infectious organisms such as parasites which grow in the meat, make proper handling and preparation of meat products essential.
In this chapter the focus is on processed meat products and not the sale of fresh meat for direct consumption. However, fresh meat is the raw material for processing, and a note on hygiene and handling is therefore included below.
Unlike other commodity groups in this book, there are a limited number of products made from meat. For this reason, only a few examples which may be suitable for production on a small scale, such as sausage, dried meat, and burger patties, are included. It is strongly suggested that meat products should only be considered by experienced food processors, because of the potential risks from food poisoning.
The two main methods of processing meat products are first, salting, smoking and/or drying, and second grinding to form minced meat, sausage-meat or pâté.
In this chapter, one example from each group is described ('biltong' as an example of a dried, salted meat, and sausages as an example of a ground (or comminuted) meat product). It should be noted also that there are hundreds of types of sausages, many of which are also smoked and/or dried to aid preservation. Freezing and canning are techniques not covered in this chapter. Both are excluded as they are capital-intensive operations and both have a serious risk of food poisoning which is thought to be unacceptable for small-scale producers.
Meat is a good source of easily digestible protein and contains essential amino acids which are vital for growth and maintenance of the body. It is also a good source of vitamins and minerals particularly iron. Processing, to form sausages, patties, or dried meat, does not have a substantial effect on the nutritive value when compared to normal cooking processes.
Fresh meat should be kept under refrigeration or cool storage and covered to protect it from insects and animals. Additionally, the hands and clothes of workers who handle meat should be regularly cleaned.
Salted, smoked, and dried meat
In all meat processing, the aim is twofold: to preserve the meat for a longer storage life, and to change the flavour and texture to increase variety in the diet. In smoking, the effects of heat from the smoke, and chemicals in the smoke, combine to preserve the meat. Smoke also adds distinctive and attractive flavours and colours to the meat.
In salting and curing, the main aim is preservation. This is achieved by high concentrations of salt which inhibit most microorganisms. This can be achieved by either rubbing salt into the meat (salting) or by soaking in salt solution (curing or brining). Salting or curing of meat is practiced in some countries to produce products such as salted pork or bacon.
Biltong is an example of a salted dried meat which is found in southern Africa. It consists of strips of meat which are dark brown in colour with a salty taste and a flexible rubbery texture. It is mainly used as a snack and has a shelf-life of several months under correct storage conditions.
It is produced by removing the fat and cutting the meat into thin strips. These are either soaked overnight in a mixture of salt and herbs/spices, or these ingredients are rubbed into the meat. It is then sun-dried by hanging the strips on a frame under an insect-proof mesh. If biltong is to be produced in more humid or cooler climates, a dryer could be used instead of sun-drying.
Production stages for biltong
|
Production stage |
Equipment |
Section reference |
|
Wash meat |
Clean water |
|
|
Trim the fat from the meat |
Knife |
|
|
Slice |
Cutting and slicing equipment |
17.1 and 17.2 |
|
Rub salt and flavourings into the slices |
Weighing equipment |
64.1 |
|
Dry |
Mats, racks |
|
|
Solar dryer |
23.1 |
|
|
Fuel-fired dryer |
23.2 |
|
|
Combined dryer |
23.3 |
|
|
Pack |
Traditional packaging materials |
|
|
Heat sealing machines |
47.1 |
Cutting
To cut the meat into thin slices a sharp sterilized knife can be used. For more precise slicing, electrically-powered knives are available.
Salting
There are many methods of salting the product. Usually a mixture of salt and spices is prepared (the type and amount depend on individual tastes). This is then rubbed onto the pieces of meat in order to achieve a uniform distribution. Alternatively the meat is soaked in a solution of these ingredients.
Packaging
Salted, dried meat needs to be protected from moisture pick-up and attack by insects. If the climate is dry it may be packaged in traditional materials such as jute bags and cane baskets. For more humid areas, sealed polythene bags can be used.
Ground meat products
Here, the process of grinding meat into small pieces (such as minced meat) or pastes (sausage-meat), aims to change the texture of the meat and allow it to be formed into different shapes. Most commonly, these are cylindrical sausages enclosed by a casing (skin), or flat discs (patties). Both enable more rapid cooking, and both methods allow for spices and other flavours to be included.
The process of grinding the meat does not help to preserve it, and in fact causes more rapid spoilage. This is because there is more chance for bacteria from hands or dirty equipment to become mixed with the meat. Grinding also releases enzymes from the meat which cause changes to its flavour and texture.
Therefore, if sausage or patty-making is to be considered, the operators must be thoroughly trained in hygienic processing, all equipment should be thoroughly sterilized, and all processing should be done quickly, preferably at a low temperature (below 10°C) using ice or refrigeration, to slow down bacterial growth.
Preservation is achieved after grinding by one or more methods including adding chemical preservatives, refrigeration or freezing, smoking, drying or, pasteurization. It can be seen from these factors that ground-meat products have the potential to cause food poisoning and it is strongly recommended that productions are not attempted unless the staff are fully aware of the potential risks involved, and are trained to avoid them.
The table below outlines the production stages for sausages and patties.
Chopping/mincing
The cheapest option is to use a knife, but for a more thorough and efficient chopping process, bowl-choppers are available. They are designed specifically for chopping meat to be processed into sausages. They consist of a rotating, horizontal bowl and a set of rotating vertical knives. The chopper will transform the meat into a homogenous sausage emulsion.
Manual or powered mincers/grinders may be used to produce minced meat for burger patties. They consist of a screw shaft inside a metal barrel, and a cutter/die assembly at the end of the barrel. As the handle is turned, the screw rotates and the minced meat is pushed along the barrel, chopped by the knives, and forced out through the die.
Production stages for sausages and patties
|
Process product |
Wash meat |
Mince/chop |
Add ingredients |
Form/mould |
Extrude |
Fill into skins |
Pack |
|
Patties |
* |
* |
* |
* |
|
|
* |
|
Sausages |
* |
* |
* |
|
* |
* |
* |
Equipment required
|
Processing stage |
Equipment |
Section reference |
|
Washing |
|
|
|
Mince/chop |
Cutting, slicing and dicing equipment |
17.1, 17.2 and 17.3 |
|
Bowl chopper |
12.2 |
|
|
Mincers and shredders |
42.0 |
|
|
Add ingredients |
Weighing and measuring equipment |
64.1 and 64.2 |
|
|
Form/mould Burger press |
53.3 |
|
Extrude |
Extruding machines (cold) |
27.2 |
|
Casing (skin) |
Filler |
28.2 |
|
Pack |
Heat sealing machine |
47.1 |
Forming/moulding
Burger patties can be moulded by hand. The mixture is weighed into portions of the correct size, and moulded and pressed by hand. Whilst this method is effective, it also gives opportunity for bacteria from workers to contaminate the patty. Alternatively, burger and patty moulds are available quite cheaply or they can be easily fabricated from local materials.
Extrusion
Sausages are prepared by forcing the ground-meat mixture into casings. Extrusion can be achieved by using a hand-held plunger such as a piston type, which may be fitted with a range of different sized nozzles.
Packaging
These products are mostly sold uncooked. If not purchased at the site of production, they should be kept under refrigeration. In terms of packaging they require a covering to prevent contamination by insects and dirt. Refrigeration slows down the actions of enzymes and micro-organisms to give a shelf-life of 1-7 days. In the raw state there is a high risk of bacterial infection, and the need for refrigeration requires expertise and strict control over hygiene. These products may also be frozen to give the product a longer shelf-life of up to six months.
The potential hazards of infection, food poisoning and product deterioration make meat processing largely unsuitable for small-scale food processors. Only people with knowledge and experience of these hazards during routine production should consider becoming meat processors.
