Food stabilizing potential of nisin Z produced by wild Lactococcus lactis subsp. lactis from raw milk and some fermented products
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In this study, we evaluated food stabilizing potential of nisin Z produced by wild Lactococcus (Lc.) lactis subsp. lactis from a total of 114 raw milk and naturally fermented products. After microbiological cultivation of lactic acid bacteria, Lc. lactis subsp. lactis strains identified by mass spectrometry were screened for the nisin Z gene by PCR. Nisin Z-production activity was studied under batch fermentation conditions, followed by testing food stabilizing potential of nisin Z extracted. Of 35 Lc. lactis subsp. lactis identified, 3 were nisin Z-producer, and one strain (e69) of natural cheese origin produced 2350 IU/mL at 63 ◦C for 30 min and 80 ◦C for 10 min, at pH 2.0. This nisin Z purified was moderately inhibitory on Gram (− ) bacteria, stable at − 20 ◦C and 4 ◦C during 6 weeks, influential on the shelf life of UHT milk and fruit juice at 30 ◦C from 2 to 6 weeks, and susceptible to lipase (89%), pepsin (92%) and catalase (84%) at 37 ◦C for 60 min, respectively. Overall, our study revealed that wild Lc. lactis subsp. lactis exhibited good activity in nisin Z production and native “clean-label” bio preservative potential for consumers and the food industry without biotechnological adaptation.