Introduction. The longer storage period is required to obtain beef meat of an adequate tenderness. Its microbiological condition is determined by such factors as type of the meat, the packaging method, as well as the applied technological processes. The aim of this paper was to compare the concentration of microorganisms (aerobic bacteria, lactic acid bacteria and bacteria of the family Enterobacteriacea) in the longissimus dorsi muscle (rump cut) and in the semimembranosus dorsi muscle (heel of round), stored at 5°C and in both aerobic and vacuum conditions. The brine containing 1% NaCl or 1% NaCl and 0.3% pentasodium triphosphate E 451 was applied to improve the meat tenderness.
Material and methods. The types of beef meat: rump cut (R) and the heel of round (L) were used as the materials in this experiment. The meat was cured either using the brine A, containing 1% NaCl in total weight, or the brine B, containing 1% NaCl and 0.3% pentasodium triphosphate E 451 (including 56% P2O5). The samples were either vacuum packaged (P) or left in open containers (T) and cold stored (5°C) for 1, 3, 7, 10 and 15 days. The total amount of mesophilic aerobic bacteria, the amount of lactic acid bacteria, the amount of bacteria of the family Enterobacteriaceae (including coliform bacteria and E. coli) and pH value were determined after each period of the storage.
Results. Comparing to aerobic storage, the vacuum storage confined the growth of microflora in the beef meat, with the biggest effect found in case of aerobic bacteria. The higher concentration of lactic acid bacteria was found in the period up to 10th day of the storage in comparison with the beef stored in aerobic conditions. In the longer period, the differences depend on the type of the muscle and the type of the applied brine. Higher concentration of bacteria of the family Enterobacteriacea in vacuum packed meat was found
in the heel of round than in the rump cut.
Conclusions. The microbiological contamination of beef stored at 5°C is statistically significantly affected by not only the time of storage, but also the type of the meat elements, as well as the applied technological processes.