Abstract:

In order to study the relationships between microbial growth and quality of pork and to establish the models forecasting growth of microorganisms, the main microorganisms causing the spoilage of chilled pork were isolated and identified using basic medium and a variety of selective media in this study. During 4 ℃ storage, chilled pork was analyzed for pH value, muscle color, water activity, water holding capacity, tenderness, and numbers of the main spoilage microorganisms. The experiments were done at intervals of 2 d from the first day until the eleventh day. The pH at first declined and then rose. The redness a * of chromatic aberration kept descending, the b * increased after the first drop, and the L * had a integrated change with the drop of a*, the increase of b* and the increase of water-holding capacity. Little change was found in the water activity. The water holding capacity was be found to gradually decline. The tenderness exhibited a trend of first increase and then decrease. The logarithmized total number of microorganisms and individual numbers of the main spoilage microorganisms could be simulated on a few fitted equations with storage time as an independent variable. The equations were different from each other, but all of them were consistent with the theoretical ones. Temperature and pH affected the growth of microorganisms, while other factors did not. There was a positive correlation between the logarithm of total number of microorganisms and the meat quality, pH value, and cooking loss, with a significant difference (P < 0.05), while the logarithm of total number of microorganisms was negatively correlated with the redness a* of chromatic aberration (P <0.05).

Key words: chilled pork, main spoilage microorganism, forecasting of microbial growth