Thanatin peptide reduces bacterial loads by up to 4.20 log CFU/mL in diverse food matrices, extending shelf-life.

Food safety and quality are severely compromised by foodborne pathogenic and spoilage bacteria, particularly Gram-negative species. Traditional antimicrobial strategies often fall short, either lacking broad-spectrum efficacy or negatively impacting product integrity. The urgent need for novel, effective, and safe antimicrobial agents is driven by the increasing prevalence of multidrug-resistant (MDR) bacterial infections. Thanatin, an antimicrobial peptide (AMP) that targets the lipopolysaccharide transport (Lpt) system, offers a promising mechanism against Gram-negative bacteria, but its direct application in food systems has been underexplored.

Researchers systematically evaluated the antibacterial efficacy and food preservation potential of Thanatin against key foodborne pathogens (Escherichia coli, Salmonella spp.) and spoilage bacteria (Pseudomonas aeruginosa). Initial characterization included determining minimum inhibitory concentrations (MIC), assessing biofilm clearance and prevention, and evaluating membrane-disruptive effects. Cytocompatibility was tested on mammalian cells. For food applications, Thanatin was applied to diverse food matrices including chilled pork, lettuce, salmon, water, and chicken breast. The study measured reductions in both indigenous and inoculated bacterial loads and assessed shelf-life over 7 days of refrigerated storage at 4 °C, monitoring total viable counts, coliform counts, pH, TVB-N values, color, texture, and water-holding capacity.

Thanatin demonstrated potent antibacterial activity, with MIC values ≤ 64 μg/mL against tested Gram-negative bacteria. It also exhibited notable biofilm clearance, achieving an average removal rate of 36.84%, alongside significant biofilm prevention effects. Mechanistically, Thanatin induced membrane-disruptive effects, consistent with its Lpt system targeting. Importantly, it showed good cytocompatibility, with mammalian cell viability remaining >90%. In various food matrices, Thanatin effectively reduced bacterial loads:

Treated samples showed up to a 4.20 log CFU/mL reduction in both indigenous and inoculated bacterial populations, significantly delaying microbial growth. Shelf-life assessments confirmed that Thanatin treatment during 7 days of refrigerated storage (at 4 °C) resulted in lower total viable and coliform counts compared to controls. Furthermore, treated samples maintained better quality, displaying decreased pH and TVB-N values, and improved color, texture, and water-holding capacity.