Developing a new spoilage potential algorithm and identifying spoilage volatiles in small yellow croaker (Larimichthys polyactis) under vacuum packaging condition

The study aims to develop a new potential algorithm to quantify the spoilage degree in the blocks of croaker packaged under vacuum condition at 4 °C. Firstly, 3 high spoilage potential bacteria isolated from contaminated blocks of croaker were used as test bacteria in storage experiments. During chilled storage, the chemical indexes of each inoculated blocks of croaker were examined every two days, including total viable count (TVC), total volatile base nitrogen (TVB-N), trimethylamine (TMA), and K value was examined to indicate the freshness of small yellow croaker. Based on these parameters, a new method to quantify spoilage potential of small yellow croaker was established by using a calculus formula. In the parallel experiments, the spoilage volatiles of each Specific Spoilage Organism (SSO)-inoculated groups with positive correlation to TVB-N value (R-value > 0.85) were identified by GC-MS, while S. glacialipiscicola and C. maltaromaticum groups possessed highest alkanes, as shown in principle component analysis plot. The study provided a more comprehensively spoilage potential algorithm and proposed a rapid detection method of contaminated SSOs by analyzing the correlation between spoilage volatiles and TVB-N.