Evaluation of in situ spoilage ability of common facultative anaerobic bacteria and confirmation of volatile spoilage markers in vacuum-packaged lamb

Microbial growth causes lamb spoilage. This study explored the spoilage ability of Latilactobacillus sakei, Serratia proteamaculans and Hafnia proteus in vacuum-packed raw lamb, including growth ability, degradation of protein and lipid, and change of volatile organic compounds (VOCs) profile, meanwhile screened the key VOCs produced by the targeted strains with meat background excluding, finally confirmed the volatile spoilage marker of vacuum-packaged lamb by comparing with our previous work. The results showed that L. sakei, S. proteamaculans and H. proteus had excellent growth ability. L. sakei inoculated group significantly reduced the pH value, showed higher trichloroacetic acid-soluble peptides content, and excellently degraded sarcoplasmic and myofibrillar proteins. About free amino acids, L. sakei significantly degraded serine, arginine and aspartic acid, while S. proteamaculans and H. proteus significantly degraded serine and lysine. In addition, L. sakei had the strongest effect on promoting free fatty acid production, followed by S. proteamaculans and finally H. proteus. Evaluating from various indicators, the co-culture of the three strains did not have any effect. The key volatiles produced by L. sakei were 1-hexanol, acetic acid and hexanoic acid, S. proteamaculans produced 1-hexanol and acetoin, and H. proteus produced 1-hexanol, acetic acid and acetoin. In the end, 1-hexanol, hexanoic acid and acetoin were proven to be spoilage markers for vacuum-packaged and chilled lamb. This study can provide fundamental information for inhibiting and rapid identification of spoilage in vacuum-packaged lamb.