The influence of vacuum packaging on microbiological status and sensory properties of fresh beef

Abstract

The packaging method can significantly affect the shelf life of fresh meat, and consequently the microbiological status and sensory properties of the packaged meat. In our country, for extending the shelf life of meat and meat products, the vacuum-packaging and packaging in the modified atmosphere are usually used. Vacuum-packaging favours the growth of facultative anaerobic bacteria, including lactic acid bacteria, Enterobacteriaceae and Brochothrix thermosphacta, as proven spoilage bacteria of fresh meat. Vacuum packaging has a positive influence on juiciness, tenderness, flavor and ripening of meat, but it has negative influence on the meat color. The aim of the present study was to investigate the microbiological status and sensory properties of vacuum-packaged fresh beef. Samples of beef tenderlo in packaged in stretch foil and vacuum-packaged fresh beef tenderloin were kept in strictly controlled conditions, at 0-4°C. Microbiological and sensory examinations were performed on 1st, 7th, 14th, 21st and 28th day of storage, in three separate cycles. Microbiological examinations included determination of microbial indicators of the processing hygiene and microbial indicators of meat spoilage (total count of aerobic mesophilic and psychrophilic bacteria, the number of Enterobacteriaceae, the number of lactic acid bacteria, the number of Brochothrix thermosphacta) and determination of pathogens (Salmonella spp., coagulasepositive staphylococci, sulphite-reducing bacteria, E. coli, Listeria monocytogenes) as well. Sensory properties were evaluated by using quantitative-descriptive test, on a scale of 1 to 5. The following properties were evaluated: appearance of meat, the color of meat surface, the color of the meat intersection, structure, texture, smell of the fresh meat, smell of meat after cooking, taste of meat after cooking and roasting. By sensory analyses spoilage of meat was established on 21st day of investigation, in the first cycle and on 28th day, in the third cycle. Results obtained from microbiological examinations indicated meat spoilage on the same days, as well. In the second cycle of investigation the meat spoilage was established on 14th day of storage, although the microbiological results did not indicate the meat spoilage.