Antimicrobial activity of whey protein films supplemented with Lactobacillus sakei cell-free supernatant on fresh beef

The aim of this work was to evaluate the antimicrobial activity of whey protein isolate (WPI) films supplemented with Lactobacillus sakei NRRL B-1917 cell-free supernatant on beef inoculated with Escherichia coli ATCC 25922 or Listeria monocytogenes Scott A; additionally, sensory evaluation was performed on wrapped beef cubes. Supernatant concentrates were obtained from Lb. sakei cultures in MRS broth after centrifugation, filtering, and freeze-drying. Films were prepared with WPI (3% w/w), alginate (0.625% w/w), rehydrated supernatant (18 mg/ml), and glycerol. Films were used to wrap beef cubes inoculated with ≈103 CFU/g E. coli or L. monocytogenes. Sensory evaluation was carried out on grilled beef wrapped or not with the studied antimicrobial films. During refrigerated storage, antimicrobial films reduced 1.4 log10 CFU/g of L. monocytogenes after 120 h, while E. coli decreased 2.3 log10 CFU/g after 36 h. Grilled beef wrapped with antimicrobial film was well accepted by panelists, besides scores evidenced no significant differences (p > 0.05) between wrapped and unwrapped beef. •Films supplemented with L. sakei supernatant exhibited antimicrobial activity.•Antimicrobial protein films decreased E. coli and L. monocytogenes counts on beef.•No sensory differences were detected between grilled beef, wrapped with film or not.