Abstract:

A mixed preservative consisting of citric acid, sodium diacetate and nisin was explored to prolong the storage
time of low-salt Xiangxi bacon. Effects of the three preservatives individually and in combination on bacterial inhibition in
Xiangxi bacon were investigated. Response surface methodology was used to optimize their combined concentrations using
bacteriostatic rate as the response variable. The results showed that citric acid, sodium diacetate and nisin displayed strong
inhibition effects on the growth of bacteria in low-salt Xiangxi bacon. Synergic effects existed between diacetate and nisin
and between citric acid and nisin, and nisin had a stronger synergistic effect with diacetate than with citric acid, whereas no
synergic effect was found between citric acid and sodium diacetate. The optimal combination of preservatives found was
1.20 g/kg citric acid, 0.97 g/kg sodium diacetate, and 0.16 g/kg nisin. The percentage inhibition of bacterial growth in
Xiangxi bacon with the mixed preservative was 95.98% and the storage time was 160 days.

Key words: nisin, sodium diacetate, citric acid, mixed preservative, low-salt Xiangxi bacon