Use of Bacteriocinogenic Cultures without Inhibiting Cheese Associated Nonstarter Lactic Acid Bacteria; A Trial with Lactobacillus plantarum

Abstract

Bacteriocinogenic cultures can represent a natural way to increase the safety of cheeses made from raw milk, in which a relevant role in ripening and flavor formation is exerted by the nonstarter lactic acid bacteria (NSLAB). Since the latter can be inhibited by bacteriocin producers, this study evaluated to which extent a nisinogenic culture inoculated at low initial levels can affect the growth rate and peptide degradation activity of the nisin-sensitive cheese isolate Lactobacillus plantarum LZ by comparison with its isogenic variant, L. plantarum LZNI, with increased immunity to nisin. A growth delay of the nisin sensitive strain was observed only when its initial number was 100-fold lower than the nisin producer and nisin was added as an inducer of its own production. In this case, the amount of free α-amino groups was significantly different between cultures of L. plantarum LZ and LZNI only at Day 1. Reverse Phase High Performance Liquid Chromatography (RP-HPLC) highlighted a few differences between the peptide profiles of co-cultures L. plantarum LZ and LZNI. However, results showed that the bacteriocin producer did not dramatically influence the behavior of the sensitive NSLAB and that the evaluation of the effects on microbial contaminants in cheese is worthwhile.

Impact of Nisin-Producing Strains of Lactococcus lactis on the Contents of Bioactive Dipeptides, Free Amino Acids, and Biogenic Amines in Dutch-Type Cheese Models

“…lactis allowed to limit the content of biogenic amines in cheeses produced from raw goat's milk [20], which suggests that bacteriocinogenic cultures can also be used to limit the formation of undesirable ingredients in cheese. Rossi and Veneri [21] show that bacteriocinogenic cultures had no inhibitory effect on the NSLAB group, which plays a significant role in the maturation and production of typical cheese sensory traits. In turn, research on the use of strains producing bacteriocins in the production of Cheddar cheeses to limit the development of NSLAB responsible for causing defects in these cheeses [23] shows the effectiveness of using these strains.…”

“…LAB peptidases are intracellular enzymes, and therefore bacterial lysis may play a major role in accelerating cheese maturation by favoring the access of enzymes to their substrates [18][19][20][21][22]. The use of the nisin-producing strain of L. lactis subsp.…”

Characterization of Lactic Acid Bacteria in Pecorino di Farindola Cheese and Manufacturing with a Lacticaseibacillus paracasei Autochthonous Culture

“…In particular, M17 medium is commonly used to count and isolate lactic cocci. However, this medium also sustains the growth of lactobacilli so that lactic cocci are not detected when lactobacilli predominate in the sample [27]. Most of the bacteria enumerated on M17 medium were of coccoid shape until day 14.…”