Effect of slightly acidic electrolysed water against Shewanella baltica in phosphate-buffered saline and on golden pomfret sticks

Shewanella baltica is a common spoilage bacterium in fish during refrigerated storage. This work aims to evaluate the effect of slightly acidic electrolysed water (SAEW) against three S. baltica strains (ABa4, ABe2, and BBe1) and to explore the antibacterial mechanism. SAEW showed high antimicrobial activity against S. baltica in phosphate-buffered saline (up to 3.82 log CFU/mL) and on fish sticks (up to 1.40 log CFU/g). This sanitising efficiency enhanced as the free available chlorine concentration of SAEW increased. Strain ABa4 showed the highest resistance to SAEW among three strains in different media. SAEW induced the accumulation of intracellular reactive oxygen species (ROS), lowered intracellular adenosine triphosphate (ATP), and resulted in the shrunken cell and irregular cell surface of S. baltica. After treatment, the contents of most amino acids and organic acids decreased. The metabolic response of S. baltica revealed that pathways about amino acids, carbohydrates, nucleotides and nicotinate were disturbed by SAEW. These results suggest that SAEW is a promising antibacterial approach to prolong the shelf-life of fish and fish products.