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.

In the food processing industry, hygiene is the key measure to eliminate the pathogens which cause food spoilage. These spoilage microorganisms are persistent sourcing a problem to the processing industry. It stresses the whole environment of food processing. Processing facilities suffer from microbes that suites the microbiota of raw material. These microorganisms grow in the form of biofilm, which is slimy and are hard to eradicate. The conventional methods of eradication of these biofilms can How to cite this article:

Oral polio vaccine (OPV) proved to be superior in administration eliminating the need of sterile syringes and making the vaccine more suitable for mass vaccination campaigns. Poliovirus is heat sensitive in nature, and thus OPV is stored at low temperature (frozen). The growth medium containing varying concentration of serum such as 6, 8, 10, 12, 14% were prepared. 10 ml of the above mentioned growth media containing different concentration of serum were added to different culture bottles. The culture flasks containing different volumes of growth medium with 10% serum concentration such as 8, 9, 10, 11 and 12 ml were added to a series of culture flasks. All the culture flasks were inoculated with the RD cells (10,000 cells/culture flask) and kept at 37°C. The most favoured serum concentration and volume for the growth of RD cells was found and used for testing the potency of vaccine. Vaccines from two manufacturers were kept at three different temperatures, 2-8 ± 0.5°C (refrigerator), 26 ± 0.5°C and 37 ± 0.5°C (Incubator). Cytopathic viruses were titrated by the determination of a tissue culture infectious dose 50 (TCID 50 ), vaccine dilutions were seeded in replicate onto cells in multiwell plates (usually 96 wells). After a suitable incubation period, wells were examined microscopically and scored as infected or not infected. The potency of vaccines was tested using the Karber's Formula.