Compound probiotics starter: A solution for aflatoxin B1 reduction and meat quality improvement in fermented chicken jerky

This study investigated the effects of compound probiotics (CP) as starter cultures to reduce AFB₁ residues and improve safety and quality of chicken jerky. First, Enterococcus faecalis, Candida utilis, Lactobacillus casein, and Bacillus subtilis were subjected to single strain fermentation experiments. Then, a three-factor, three-level response surface methodology design was used to select the CP based on AFB₁ degradation and histamine content. The optimal CP included Candida utilis, Lactobacillus casein and Bacillus subtilis at initial viable counts of 3.0 × 10⁸, 3.0 × 10⁹ and 3.0 × 10⁹ CFU/mL respectively, and then mixed at a volume ratio of 1:1:1. Each AFB₁-contaminated chicken strip was fermented with 0.15 mL CP at 30 °C for 40 h then dried. AFB₁ and histamine contents were reduced by 90.18% and 9.74% in fermented jerky, compared with the unfermented jerky (P < 0.05). Amino acid analysis showed lower serine and histidine contents and higher cysteine content in the fermented jerky. 16S rRNA sequencing unveiled a reduction in the absolute abundance of Staphylococcus saprophyticus. According to metabolomics and proteomics, CP inhibited methionine metabolism and increased lactic acid and alanine accumulation through cysteine and methionine pathways (KEGG map ID: map 00270), thereby maintaining low pH and improving flavor/safety. The results thus confirmed that C. utilis, L. casein, and B. subtilis are potential meat product starters.