为研究真空包装冷却牛肉贮藏过程中微生物和各品质指标的变化,确定理化指标和微生物指标的相关性,测定了于4℃贮藏的真空包装冷却牛肉在0、7、13、21、28、38 d的菌落总数、乳酸菌、假单胞菌、热杀索丝菌、肠杆菌5个微生物指标及pH值、挥发性盐基氮、系水力和色差值4个品质指标的变化情况,并确定了各指标随贮藏时间的动态变化规律及相关性。结果表明,在贮藏期间,菌落总数和乳酸菌的变化趋势相同,假单胞菌、热杀索丝菌和肠杆菌等生长迅速;pH值为先下降后上升趋势;色差值a*值、C*ab初期上升,后期小幅下降;挥发性盐基氮值初期平稳上升,后期快速增大;系水力逐步上升。菌落总数与乳酸菌呈现极显著相关的关系(P<0.01),与挥发性盐基氮值、a*值、b*值、C*ab及系水力显著相关(P<0.05)。由此可知,微生物的生长引起牛肉品质变化,挥发性盐基氮值、a*值、b*值、C*ab可以作为判断真空包装牛肉腐败指标。

In order to study changes of the microbiology and meat quality of the vacuum-packaged beef and the correlation between their chemical index and microbiological index,we measured total viable count,lactic acid bacteria,Pseudomonas spp.,Enterobacteriaceae,Brochothrix thermosphacta,pH value,total volatile basic nitrogen(TVBN),water holding capacity,meat color of chilled beef and their correlations at 4℃ on the 0,7,13,21,28,and 38 days.The results showed that the change of the total viable count and the lactic acid bacteria were the same,that Pseudomonas spp.,Enterobacteriaceae,Brochothrix thermosphacta grew rapidly.The pH value decreased at first and then rose.The color increased at first then decreased little later.The TVBN value slowly rose in the early days and rapidly rose in the later days.The water holding capacity at 4℃ increased steadily.During the storage,there was a significant correlation between total viable counts and lactic acid bacteria(P<0.01) and there was also a correction between the total viable counts and TVBN value,a* value,b* value,C* ab and the water holding capacity(P<0.05),but there was little correction between total viable counts and pH value,L* value.Therefore,the meat quality changed because of the growth of the microbiology,and TVBN value,a* value,b* value,C* ab could be used as the indicator of meat spoilage.