EFFECT OF MODIFIED ATMOSPHERE AND VACUUM PACKAGING ON THE GROWTH OF SPOILAGE AND INOCULATED PATHOGENIC BACTERIA ON FRESH POULTRY

Fresh chicken breast meats inoculated with Yersinia enterocolitica and Aeromonas hydrophila were packaged in glass jars containing different compositions of modified atmospheres (MA) (100% CO2; 80% CO2/20% N-2) , in vacuum and in air and stored at 3+/-1 degrees C and 8+/-1 degrees C. The changes in gas composition, Y. enterocolitica, A. hydrophila, total aerobic bacterial, total psychrotrophic, Lactobacillus and Enter obacteriaceae counts were determined after 0, 1, 3, 7, 9, 11, and 14 d ays of storage. The results show that while the growth of Y. enterocol itica and A. hydrophila were retarded under MA storage, the pathogens were capable of growth in MA and vacuum storage at both temperatures, for studying inoculation levels. For total aerobic bacterial counts, t here were no differences between chicken breasts meats held in differe nt atmospheres. Co-2 packaging has the highest inhibiting effect on th e growth of psycrotrophic aerobic bacteria during the first 3 days. La ctic acid bacteria of samples stored in MA and in vacuum increased rap idly when compared to those stored in air. It was also found that, the effect of MA storage increased at 3+/-1 degrees C.