Characteristics of frozen beef according to biochemical and microbiological parameters

Abstract

Goal. To assess methods of storing frozen beef according to microbiological and chemical indicators. Methods. Microbiological and biochemical studies of fresh and frozen beef aiming at the determination of the indicators of freshness and microbiological safety were carried out by standard and generally accepted techniques. Results. It was found that the number of mesophilic microorganisms on fresh beef carcasses (24 h) was 12.7 times higher as compared to the number of psychrotrophic microorganisms. During 8-months’ storage of beef in a frozen state (–12°C) the number of mesophilic aerobic and optional anaerobic microorganisms decreased 7.8 times, Enterobacteriaceae — in 16.8, psychrotrophic microflora — only in 1.6 times. At the same time, fungal microflora for these storage modes increased 1.7 times. When storing beef at a temperature of –20...–25°C for 14 and 18 months, the gradual dying of microflora on its surface was revealed. At the same time, the amount of mesophilic and coliform microflora decreased on a larger scale — about 10 and 24 times, respectively. The number of psychrotrophic microflora thus decreased only 1.8 times against the initial amount, and the fungal one remained unchanged. Within 8-months’ storage of beef at –12°C deterioration was revealed of indicators and its freshness. At the same time, for storage of meat at –20...–25°C for 14 and 18 months, the presence of volatile fatty acids indicates its doubtful freshness. Also, the growth of products of peroxide oxidation of lipids is fixed in beef with long-term storage at –12°C. Conclusions. When storing beef in a frozen state at a temperature of –12°C for 8 months the development of mesophilic and psychrotrophic microflora is stopped. The most detrimental temperature of –12°C influences mesophilic and coliform bacteria. At the same time, the propagation of fungal microflora on the surface of the carcass is fixed. When storing beef at –20...–25°C for 14-18 months the microflora on its surface did not multiply, but gradually died. Within 8-months’ storage of beef at -12°C the deterioration was revealed of biochemical indicators of its freshness. At the same time, for storage at – 20...– 25°C for 14 and 18 months, beef had questionable freshness only by the content of volatile fatty acid.