Background: The use of lytic bacteriophages for the biocontrol of food borne pathogens is gaining interest. In recent years it has become widely recognized that bacteriophages have several potential applications in the food industry as a biocontrol agent. Seafood industry is still using chemicals to control the food borne bacterial pathogens which may adversely affect consumer health. Hence this study has been under taken to control food borne Salmonella infections in peeled and deveined (PD) shrimp using bacteriophage.
Methods: Salmonella phage was isolated from raw sewage sample by using Salmonella typhimurium (MTCC 1264) as the host bacterium. The host range specificity of Salmonella specific bacteriophage isolated in the current study was checked using different bacterial strains by spotting technique. The efficacy of the isolated Salmonella phage as a biocontrol agent against Salmonella was checked by conducting challenge experiments in PD shrimp by collecting samples from all the controls and treatments at four time intervals viz.0th, 3rd, 6th, 9th h.
Findings: The results showed that the log reduction between the positive and treatment trials at 0th and 3rd hour interval as 0.24 and 0.95 log unit respectively (p>0.05). But from 6th hour onwards the host bacterial count showed high reduction in Salmonella count when compared to 0th and 3rd hour (p<0.05). At the 6th hour, the Salmonella count obtained for the positive control was 3.08×103 cfu/ml and for the treatment, the bacterial count was 1.4 × 101. The log reduction in host bacterial count between the positive and treatment at 6th hour was 2.34 whereas at 9th hour the log reduction was 2. 51 log unit (p<0.05).
Conclusion: Hence the study shows the potential effectiveness of this isolated Salmonella phage as a biocontrol agent of Salmonella typhimurium in PD shrimp.
Sutapa Biswas and Dr. Safeena M.P