Effects of exogenous AHLs on the spoilage characteristics of Pseudomonas koreensis PS1

Some specific spoilage organisms (SSO) respond to the presence of exogenous N-acyl-homoserine lactones (AHLs) through the quorum sensing (QS) system to modulate their spoilage characteristics. To explore the effect of exogenous AHLs on the spoilage characteristics of Pseudomonas koreensis PS1 from spoiled chilled pork, four kinds of AHLs were added to the liquid medium to analyze their effect on the cell growth and spoilage characteristics of P. koreensis PS1, and N-hexanoyl-l-homoserine lactone (C6-HSL) was added to evaluate its effect on spoilage characteristics of P. koreensis PS1 inoculated in fresh chilled pork. The results showed that the addition of low concentrations of C6-HSL (10 µmol/L) to the liquid medium could remarkably promote the protease activity, lipase activity, and biofilm formation of P. koreensis PS1 (p < 0.05), and more than 30 µmol/L C6-HSL could significantly increase the cell density (p < 0.05). Furthermore, the addition of 10 µmol/L C6-HSL into fresh chilled pork could increase the lipase and protease activities of P. koreensis PS1. The enzyme activity accelerated the decomposition of total protein, total fat, and total sugar, and led to an increase in putrescine, tyramine, cadaverine, and total volatile basic nitrogen (TVB-N) content in chilled pork during the storage at 4°C. PRACTICAL APPLICATION: The infestation of chilled pork with SSO may be a challenge for the meat industry. In this study, exogenous AHLs were found to have a positive effect on the spoilage of chilled pork. The elimination of the QS phenomenon of bacteria should be considered when looking for ways to prolong the preservation of chilled pork.