Isolation of a Bacteriocin-Producing Lactococcus lactis and Application of Its Bacteriocin to Manage Spoilage Bacteria in High-Value Marine Fish Under Different Storage Temperatures

Abstract

The bacteriocins of lactic acid bacteria have considerable potential for biopreservation. The Lactococcus lactis strain PSY2 (GenBank account no. JF703669) isolated from the surface of marine perch Perca flavescens produced antibacterial activity against pathogenic and spoilage-causing Gram-positive and Gram-negative bacteria viz. Arthrobacter sp., Acinetobacter sp., Bacillus subtilis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus and possessed broad inhibitory spectrum. The biopreservative efficacy of the bacteriocin PSY2 was evaluated using fillets of reef cod, Epinephelus diacanthus. The fillets (10 g) were sprayed with 2.0 ml of 1,600 AU/ml bacteriocin, wrapped and kept under different storage temperatures viz., 4, 0 and −18°C. The biopreservative extended the shelf-life of fillets stored at 4°C to >21 days as against <14 days observed in the untreated samples. The total count of spoilage bacteria was reduced by 2.5 logarithmic units in the treated sample during the 14th day of storage as against the control. Chemical analysis revealed a significant change (P<0.05) in the pH value, free fatty acid (as % oleic acid), total volatile base nitrogen and total methyl amine content in the treated samples. The overall acceptability in terms of sensory attributes was significantly higher in the bacteriocin-treated samples stored for 21 days at 4°C while the untreated samples became unacceptable by the 14th day. The biopreservative gave no significant effect at −18°C. Thus, the bacteriocin derived from L. lactis PSY2 gave increased protection against spoilage bacteria and offers an alternative for the preservation of high-value sea foods.

Effects of dietary enrichment with alpha-tocopherol acetate and post-harvest filleting on lipid oxidation and flesh quality of tropical farmed barramundi (Lates calcarifer)

“…The pH of fish flesh is frequently observed to increase during chilled storage (Gildberg, 1978;Ruff et al, 2002;Sarika et al, 2012). This can be attributed to the production of volatile bases by bacteria within the tissues as glycogen is utilised as an energy source, as well as to the actions of heterofermentative lactic acid bacteria which grow and degrade amino acids with the formation of carbon dioxide and other decarboxylation products (Sarika et al, 2012). In this study, we observed increases in pH in whole ungutted fish whilst the pH of filleted fish remained stable and appeared to decrease in unenriched fillets during storage.…”

Synergistic antimicrobial action and potential application for fish preservation of a bacteriocin produced by Enterococcus mundtii isolated from Odontesthes platensis

“…Therefore, for a possible use in fishery products, bacteriocins would be more adapted to the substrate (Calo-Mata et al, 2008). However, the study of the use of bacteriocins as fish preservatives has been focused on their antilisterial activity and not in their ability to control the growth of spoilage bacteria or their combined use with other antimicrobials (Sarika, Lipton, Aishwarya, & Dhivya, 2012;Vescovo et al, 2006).…”

The effects of Lactococcus lactis subsp. lactis and its supernatant on some bacteriological and sensory values in Rainbow trout (Onchorhynchus mykiss) fillets

“…17 Psychrophilic bacteria limitation in fish fillet is 7 logCFUg -1 . 19 According to results of day 15, in 2% treatment of immersion method and control until day 15 the number of psychrophilic bacteria exceeded from 7log CFUg -1 that were 7.31±0.03, 7.51±0.22 logCFUg -1 , respectively (Figure 1). In samples with 4% supernatant and live cells with concentration of 6log CFUg -1 , the number of psychrophilic bacteria on 15th day were 5.36±0.09, 4.25±0.06 logCFUg -1 , respectively ( Figure 1) that were less than human consumption limit.…”

“…2%, 4% solutions of this supernatant were prepared using distilled water. [13][14][15][16][17][18][19][20][21] Pure bacteria of lactic acid bacteria preparation Serial dilutions were prepared and then pour plated in solid nutrient broth culture, made by Merck Co. Germany, medium and incubated in 30°C to count the grown colonies after 48 hours and stored in the refrigerator to avoid the further growth of bacteria during the colony counting and the initial concentration of our solution were obtained. Concentration of 10 6 ml -1 were prepared that in this work we call it live cells or pure bacteria of L. lactis subsp.…”

“…[12][13][14][15][16][17][18][19][20][21] The aim of this study was to use L. lactis subsp. lactis (PTCC1336) as LAB and its supernatant as a preservative to enhance the microbial and organoleptic quality of rainbow trout fillets using two methods including immersion and spray at 4°C refrigerated temperature and vacuum condition.…”