FAO ANIMAL PRODUCTION AND HEALTH PAPER 79
Manual on simple methods of meat preservation
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© FAO 1990
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1. Slaughtering and raw materials for meat preservation
2. Simple techniques for production of dried meat
3. Meat preservation by thermal treatment
4. Impact of packaging methods on meat preservation
5. Basic methods of quality control
Table 1. Pistola system, primal cuts expressed in percentage of cold carcass weight
Table 2. F-values corresponding to various temperatures
Table 3. F-values in relation to temperature and time
Table 4. Decimal reduction rates during heat treatment
Table 5. Recommended thermal treatment for selected products
Figure 1 Simple wooden structure to hoist slaughter animal after bleeding
Figure 2 Removal of skin from the hanging carcass
Figure 3 Layout of the FAO small-scale modular slaughterhouse
Figure 4 Beef carcass showing primal cuts according to pistola procedure
Figure 5 Hindquarter (top) and forequarter (bottom) separated behind the last rib. (Procedure recommended for meat for drying)
Figure 6 Dehydration process of a piece of meat suspended under drying conditions (schematic)
Figure 7 Trimming a beef carcass
Figure 8 Suspended anatomic cut from the hindquarters (“silverside”) (A) and splitting into individual muscles (B) which result in (C)
Figure 9 Cutting meat strips from the muscle on a chopping board
Figure 10 Cutting meat strips from a suspended muscle
Figure 11 Special cutting technique to obtain long meat strips
Figure 12 Meat strips are soaked in a 14-percent salt solution for five minutes
Figure 13 Draining the brine from the meat strips after soaking using a plastic sieve
Figure 14 Suspension of meat strips on hooks (A), loops (B) and by means of clips (C)
Figure 15 Preparing hooks from galvanized wire
Figure 16 Preparing loops from string or thread and fixing the meat strips
Figure 17 Simple wooden construction for meat drying using sticks (A) or wire/plastic rope (B) to suspend the meat strips
Figure 18 Simple metal construction for meat drying using sticks (A) or wire/plastic rope (B) to suspend the meat strips
Figure 19 Movable metal construction for meat drying
Figure 20 Suspending meat strips on the lower level of the dryer on wooden sticks by means of metal hooks
Figure 21 Roofed meat dryer (corrugated aluminium)
Figure 22 Protecting the sides of a meat dryer with an insect screen
Figure 23 Arranging meat strips in the dryer along sticks or wires for suspension
Figure 24 Dried meat strips
Figure 25 Properly dried meat with a smooth surface and uniform cross-section
Figure 26 Dried meat strips packed in plastic bags with the opening heat sealed (above) or tied (below)
Figure 27 Dried meat in jute sacks for wholesale trade
Figure 28 Whole strips and flat pieces of dried meat and dried meat comminuted to fragments of different sizes for preparing meals
Figure 29 Preparing a meal of dried meat. As a first step the dried meat is put into boiling water
Figure 30 Retort cooker
Figure 31 Principles of can-seaming operation
Figure 32 Vacuum chamber machine
Figure 33 Electrical thermometer with digital display and two sensors, for measuring air temperature (left) and the temperature of meat, liquids, etc. (right)
Figure 34 Electronic psychrometer (hygrometer) and sensor (right) for direct measurement of the relative air humidity
Figure 35 Mechanical instrument to prove airtight closure of cans
Figure 36 Portable electric pH-meter with sensor (glass electrode)
Figure 37 Trigger and sterile cellotape for microbiological sampling of the meat surface
Figure 38 Culture medium with various fields after incubation of different samples taken using the technique shown in Fig.37
Figure 39 Sampling microbial contamination on a defined surface area marked by sterile template with sterile swabs
Figure 40 Transfer of the sample taken with the swab on to the surface of the culture medium.
Figure 41 Bacterial colonies grown from one cell each on the culture medium after the incubation period.
Although the demand in developing countries for animal proteins is increasing, animal production has failed to keep pace with the growth in demand and to make full use of its potential in developing countries.
The nutrition of resource-poor rural producers can be improved both directly by consumption of animal food products or indirectly by enabling the purchase of food with returns from animal product sales.
The average per caput supply of meat in developing countries is very low. In 1979 and 1986 it amounted to 12.7 and 15.4 kg/caput/year respectively as compared to the developed countries with 74.3 and 77.9 kg/caput/ year respectively. The average per caput supply in developing countries in Africa reached the average level of all developing countries in 1979 with 12.9 kg/caput/ year but in 1986 remained at 11.8 kg/caput/year, below the level of the developing countries combined and even below the 1979 level.
While efforts are increasing to support animal production in developing countries, they are not matched by similar efforts to use preservation to overcome seasonal variation in meat supply. In addition the existing conditions for slaughtering and meat handling in rural areas which cause quality deterioration and post-harvest losses of meat- and food-borne diseases in consumers must be improved.
In fact there is a lack of effort to provide knowledge and skills in adequate hygienic slaughtering, meat cutting and handling under rural conditions. Taking into account that an uninterrupted cold chain for meat cannot be expected in many developing countries in the near future, the absence of meat preservation techniques presents a serious constraint to the development of viable meat production by resource-poor rural livestock producers.
Adequate meat preservation complements a marketing system which by necessity has been adapted to a fast throughput of fresh meat and which does not facilitate the use of surplus meat in periods of meat shortage.
While this publication is mainly intended to disseminate information on traditional methods of meat preservation in Africa for teachers and instructors, it also addresses aspects of hygienic slaughtering under rural conditions. Reference is also made to FAO's work on small-scale slaughterhouses, raw materials for preserved meat, principles of meat preservation by thermal treatment, packaging methods and basic methods of quality control.