Dynamics in ammonia levels in the process of producing canned meat for long-term storage

Ammonia contents were studied in correlation with sensory changes in raw materials (pork and beef) used for the production of meat cans, and in relation to sensory changes at the end of their production. The following three types of meat cans designed for long-term storage were tested: Pork in Natural Juice, Beef with Bacon, and Luncheon Meat. Raw materials used for the production of meat cans had the known sensory characteristics and known ammonia values. Four groups of final products were prepared from each kind of these meat cans; the materials used for this purpose differed in their freshness. To obtain these differences in freshness, the material had been stored under constant conditions (average temperature 12.5 degrees, relative humidity 78.0%) and processed step by step in four work shifts during two days in succession. Each kind of raw material was sampled before processing into the final product and the samples of canned meat were taken after the termination of the technological process of production. The samples were subjected to sensory evaluation and the quantitative content of ammonia was determined in all of them by a microdiffusion method. In all kinds of meat the contents of ammonia evidently increased with the time of storage whereas the values of sensory evaluation declined. As indicated by measurements during the technological process of production, sterilization increases the ammonia content. The value of ammonia content in the meat cans at the end of the technological process of production indicates how fresh is the raw material. In combination with other investigations, this value can be used for forecasting the changes in canned meat in the course of long-term storage.