LPT 321: Meat Science (1+1)

Points for Consideration to Choose a Method of Preservation

POINTS FOR CONSIDERATION TO CHOOSE A METHOD OF PRESERVATION OF FOOD

• Preservation of food most often involves application of measures to delay or prevent certain changes which make meat unusable as a food or which down grade some quality aspect of it.
• Theer are several processes by which such deterioration can occur are  and they include microbial, chemical and physical processes.
• Most of the edible tissues of the healthy animal at the time of slaughter are either sterile or contain few micro-organisms, owing to the several level of defence in place against microbial invasion
• Unfortunately, these efficient defence mechanisms are nullified at the time of animal’s death.
• The momentary state of shock concomitant with exsanguination probably facilitates bacterial invasion from the intestinal tract.
• The slaughtering operation contaminates the vascular system with  numerous micro-organisms that may disseminate through the body before bleeding has been completed.
• Bleeding largely depletes the body of the circulating antibodies and leucocytes. Therefore, a sudden cessation of the body’s defence against microbial invasion and as a consequence growth of foreign micro-organisms accompany the death of the meat animal.
•  There appear to be no residual bacteriostatic or bactericidal properties in the tissues of the freshly slaughtered animal.
• Fresh meat is highly perishable because of almost neutral pH (low acid food), high moisture content and being rich in all the nutrients required for microbial growth.
• Cured and processed meats are generally more stable than fresh meats with respect to microbial deterioration because of additives such as salt or moisture reduction (as in the case with dry sausages) or a combination of these agents.
•  The widespread availability of refrigeration has decreased the need to rely on curing and processing , for example, salt levels have been reduced to meet palatability and consumer health considerations.
• Due to the greater microbial stability of such products, the other deteriorative processes can be of greater significance in them.
• For example, the colour deterioration through chemical changes under some conditions might pose a serious problem.
• Important advances in preservation have resulted through application of appropriate packaging materials and methods.
• It is essential that in evaluating a method of preservation criteria other than that of merely preventing spoilage of meat must be considered.
• Attention must be given to
  • The effect of the method on product quality
  • Any health hazards involved for either the food handler or the consumer
  • Possible misuse of the method
  • Distribution and marketing problems
  • Engineering and  evaluation of economics of the method’s commercial application.
• The recognized methods by which meat foods may be preserved are
  • Drying,
  • Salting–curing,
  • Application of low temperature – Chilling/cold and Freezing
  • Application of high temperature - Thermal Processing
  • By the usage of Chemicals, Antibiotics, etc.
  • Radiation - Ionizing radiations.