Bacteriocin from Bacillus velezensis BUU004 as a Seafood Preservative: Antibacterial Potential, and Physical and Chemical Qualities of Dried, Seasoned, and Crushed Squids

Food safety of seafood-based products has become an important health threat in Thailand. Simultaneously, potential hazards posed by the use of chemical preservatives have prompted the advent of alternative technologies. Bacteria-derived substances have attracted interest as biopreservative to respond to health conscious demand of consumers. In order to enhance biosafety quality from a farm to fork cycle of traditional seafood products, bacteriological assessment during multiple steps related to preparation of dried, seasoned and crushed squids was conducted. Total viable counts (TVC) in the ranges of 102 - 103 CFU/g were observed across a series of thepreparation from rinsing to 2nd sun-dry phases. Homemade seasoning sauce composed mainly of Thai spices and flavoring was the common source of spoilage bacteria supported by the highest TVC population and diversity. Three bacterial genera belonging to Bacillus, Kocuria and Staphylococcus existed predominantly in the prepared squids. In the subsequent phase of study, antibacterial potential, and mode of action of a semi-purified solution containing bacteriocin from B. velezensis BUU004 (SPS-BV) against pathogenic B. cereus were investigated. The SPS-BV (800 AU/mL) exhibited strong bactericidal activity towards B. cereus through cell lysis. Lastly, biopreservative potential of the SPS-BV was evaluated in the post-prepared dried squids during 28-day storage atroom temperature. The SPS-BV was as effective as commercial nisin for controlling food spoilage bacteria along with significant reductions in moisture content and aw of dried squids during storage. This study confirms the biopreservative potential of the SPS-BV in dried seafood products in Thailand.