Characterizing bacterial strains of spoiled Jinhua ham and evaluating the effect of antimicrobial agents on these isolated bacterial strains

Abstract

In order to explore effective measures to control the microbes responsible for the spoilage in Jinhua ham, spoiled ham was sampled and used to characterize bacterial strains; NaCl tolerance and ability to produce biogenic amines of bacteria strains were further determined. Total of 80 strains were isolated from spoiled ham, which 6 strains and 18 strains were identified at family level and species level, respectively; C. farmei CDC 2991–81, B. cereus ATCC 14579 and E. faecalis ATCC 19433 were main spoilage microorganisms of Jinhua ham. E. faecalis ATCC 19433 and E. faecium DSM 20477 showed higher NaCl resistance and production capacity of 2-phenylethylamine and tyramine, compared with other bacterial strains. The main producers of putrescine were strains of C. farmei CDC 2991–81 and B. cereus ATCC 14579. Nisin, sodium diacetate, citric acid, potassium lactate and potassium sorbate were active against the tested strains but at high levels. Antimicrobial interactions between binary mixtures showed that the combination of nisin and sodium diacetate had the best preservative effect on above bacteria based on the changes of fractional inhibitory concentrations index. These results indicated that the combination of nisin and sodium diacetate could be the best preservative effect against all tested strains.