Effect of proteins, glucose and NaCl on growth, biosynthesis and functionality of bacteriocins of Lactobacillus sakei subsp sakei 2a in foods during storage at 4 °C: Tests in food models

Bacteriocins produced by lactic acid bacteria are used as food biopreservatives. In consequence of amphiphilic characteristics and high content of hydrophobic amino acids, biosynthesis and antimicrobial functionality of bacteriocins can be affected by components in the food matrix. This study evaluated the influence of proteins/peptides, glucose and NaCl on growth and bacteriocins production by Lactobacillus sakei subsp. sakei 2a, using simulated food models prepared with combinations of meat extract, yeast extract, proteose-peptone, starch, glucose and NaCl. A semi-purified extract of bacteriocins was used to investigate their functionality against Listeria monocytogenes added to the models, stored at 4 degrees C for 10 days. Results were compared to those obtained with a similar extract of a non-bacteriocinogenic strain of Lb. sakei, prepared according to the same purification protocol. Results indicated that growth and bacteriocin production in the tested conditions was minimal. Glucose had a small but positive affect on both measurements. However, the functionality of the bacteriocins against Listeria monocytogenes in the models during refrigerated storage was similar, indicating that none of the components at the tested concentrations had an evident influence on the activity. These results subsidize the correct application of bacteriocins of lactic acid bacteria in protein-based foods for biopreservation.