Cover
FAO ANIMAL PRODUCTION AND HEALTH PAPER 79





Manual on simple methods of meat preservation




Contents




The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.



M-25
ISBN 92-5-102744-7



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FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1990
© FAO 1990


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Contents

Introduction

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

Illustrations

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.

Introduction

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.