Zeitschrift für Lebensmittel : Mikrobiologie, Sicherheit und Hygiene
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Milchsäurebakterien aus Meeresfischen: Antibiotikaresistenz und Produktion von Bakteriozin wirksam gegen L. monocytogenes in situ

AR Sarika*, AP Lipton, MS Aishwarya and RS Rachana mol

Objective: To determine the antimicrobial resistance of bacteriocin producing marine Lactic acid bacteria and to study the efficacy of bacteriocin against L. monocytogenes during fish preservation.

Methods: Lactic acid bacteria from scales and mucus of marine fish viz., Perca sp., Platax sp. and Tuna sp. which showed activity against different spoilage causing bacteria were subjected to antibiotic sensitivity testing. The LAB isolates were also screened for their antagonistic activity against L. monocytogenes and other pathogenic and spoilage causing bacteria by the well-diffusion method. The potent bacteriocin from L. lactis PSY2 was tested for its efficacy in combating L. monocytogenes challenged fresh fish fillets stored at different temperatures viz., 4, 0 and -18°C for 28 days and compared to that of the chemical preservative sodium benzoate.

Results: The LAB isolates showed sensitivity to antibiotics of clinical use, but resistance was detected more frequently towards ampicillin A, furazolidone, gentamycin, kanamycin norfloxacine and vancomycin. Five of the isolates viz., PSY2, MC2, MC6, TS1 and PSY1 inhibited both Gram positive and Gram-negative fish pathogenic and spoilage causing bacteria and possessed broad inhibitory spectrum. The potent isolate Lactococcus lactis PSY2 inhibited Listeria monocytogenes in vitro. The bacteriocin PSY2 effectively reduced the viable count of L. monocytogenes in the fillets stored at 4 and 0°C; however, the freezed (-18°C) sample harbored less count of the pathogen even in the control after 28 days of storage. The sensory and other physicochemical analyses also revealed the efficacy of bacteriocin PSY2 in combating L. monocytogenes under storage conditions.

Conclusion: The study concluded the inhibitory potential of bacteriocin PSY2 against L. monocytogenes during cold storage of raw fish; hence provide prospects for its’ possible application as fish biopreservative.