Packaging Methods To Preserve Meat, Poultry And Fish
The major goal of any packaging way for fresh muscle foods is to prevent or delay undesirable changes to the appearance, flavor, odor, and texture which is so called decomposition. Deterioration in these qualities leads economic losses due to consumer rejections of the product. Interms of consumer purchase mentality appearance of fresh muscle foods greatly affects the decision. During the storage of raw muscle foods like fresh meat, fin fish, fresh chicken etc… at chiller temperatures, various enzyrnemediated and non-enzymic chemical reactions will affect the flavor, odor, and texture of the tissues. Some of these changes caused by enzymic reactions are desirable – such as, the increased tenderness of aged beef. Nevertheless, most of the changes led by enzymic activities are undesirable. Therefore, a preservative packaging should ideally applied to inhibit undesirable enzymic activities, but not interfere with, or inhibit, activities that are beneficial. Considering above, there are basically four categories of preservative packaging that can be used with raw muscle foods like fresh meat, chicken, poultry, fish… These are vacuum packs, high oxygen modified atmosphere packs (MAP), low oxygen modified atmosphere packs (MAP), and controlled atmosphere packs (CAP). Vacuum packs comprise evacuated bags, in which a film of low gas permeability is closely applied to the surface of the product. Preservative effects are achieved by the development of an anaerobic environment within the pack. High O2 modified atmopshere packs (MAP) contain atmospheres of oxygen and carbon dioxide and, often, nitrogen. Only oxygen and carbon dioxide have preservative effects. However, carbon dioxide is highly soluble in both muscle and fat tissues, while oxygen may be respired by tissues and bacteria at high initial concentrations, will tend to be lost through the packaging film.