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An approach to select Lactobacillus isolates as protective cultures for food fermentations
Author(s) -
Inglin Raffael C.,
Delbrück Alessia I.,
Fässler Benjamin,
Siebenmann Katharina E.,
Lacroix Christophe,
Stevens Marc J. A.,
Meile Leo
Publication year - 2018
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/jfs.12483
Subject(s) - lactobacillus sakei , lactobacillus plantarum , microbiology and biotechnology , biology , food science , fermentation in food processing , food spoilage , lactobacillus , fermentation , listeria monocytogenes , bacteria , lactic acid , genetics
Food waste reduction can be achieved by applying protective cultures to avoid spoilage of fermented food products. In this study, we present an approach to screen large numbers of strains for potential use as protective cultures in food. A phenotypic screening of 504 Lactobacillus strains for 27 food‐relevant growth conditions revealed variations and physiological limits for the genus. Previously, the strains were tested for their antibacterial activity in a high‐throughput assay. Here, the activity of 22 positive strains from that screening was assessed in more detail, mainly against Listeria , Enterococcus , Rhodotorula , and Candida species. The proteinaceous nature of the inhibiting substances was confirmed by protease digestion. Twenty‐two antibacterial and 42 antifungal strains were detected. In a co‐culture competition‐assay, 1–2 cfu/ml of Lactobacillus plantarum RI‐162 were able to inhibit the outgrowth of Rhodotorula mucilaginosa LME and reduce the cell number below the detection limit of 50 cfu/ml within 48 hr. Practical applications To translate the result to industrial application, the potential protective culture Lactobacillus sakei RI‐409 reduced the initial Listeria ivanovii DSM 12491 T concentration in an industrial‐scale salami fermentation by 1.4 log within 5 days. In a small‐scale salami fermentation, one L. sakei strain and five Lactobacillus plantarum strains were tested as protective cultures. Four strains reduced the spiked counts of L ivanovii DSM 12491 T from an initial concentration of 10 5 cfu/g at the start of fermentation to below the detection limit of 100 cfu/g within two days. In a 1,000‐L small‐scale raw milk soft cheese fermentation, the potential protective culture L. plantarum RI‐271 reduced the endogenous enterococci concentration with 1.5 log compared to untreated raw milk. In conclusion, we have developed an approach to select tailor‐made antimicrobial protective cultures for biopreservation in fermented food products.