title: Prior frozen storage enhances the effect of edible coatings against Listeria monocytogenes on cold-smoked salmon during subsequent refrigerated storage.
abstract: OBJECTIVE
  Listeria monocytogenes is a major safety concern for ready-to-eat foods. The overall objective of this study was to investigate whether prior frozen storage could enhance the efficacy of edible coatings against L. monocytogenes on cold-smoked salmon during subsequent refrigerated storage.
  
  
  RESULTS
  A formulation consisting of sodium lactate (SL, 1·2-2·4%) and sodium diacetate (SD, 0·125-0·25%) or 2·5% Opti.Form (a commercial formulation of SL and SD) was incorporated into each of five edible coatings: alginate, κ-carrageenan, pectin, gelatin and starch. The coatings were applied onto the surface of cold-smoked salmon slices inoculated with L. monocytogenes at a level of 500 CFU cm⁻². In the first phase, the slices were first frozen at -18°C for 6 days and stored at 22°C for 6 days. Alginate, gelatin and starch appeared to be the most effective carriers. In the second phase, cold-smoked salmon slices were inoculated with L. monocytogenes, coated with alginate, gelatin or starch with or without the antimicrobials and stored frozen at -18°C for 12 months. Every 2 months, samples were removed from the freezer and kept at 4°C for 30 days. Prior frozen storage at -18°C substantially enhanced the antilisterial efficacy of the edible coatings with or without antimicrobials during the subsequent refrigerated storage.
  
  
  CONCLUSIONS
  Plain coatings with ≥ 2 months frozen storage and antimicrobial edible coatings represent an effective intervention to inhibit the growth of L. monocytogenes on cold-smoked salmon.
  
  
  CONCLUSIONS
  This study demonstrates the effectiveness of the conjunct application of frozen storage and edible coatings to control the growth of L. monocytogenes to enhance the microbiological safety of cold-smoked salmon.
authors.affiliation: Department of Animal and Food Sciences, University of Delaware, Newark, DE, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ye
authors.forename: H
authors.initials: H
authors.lastname: Neetoo
authors.forename: H
authors.initials: H
authors.lastname: Chen
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000464:Alginates / Q000494:pharmacology; D000818:Animals; D002351:Carrageenan / Q000494:pharmacology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D061353:Food Storage / Q000379:methods; D005615:Freezing; D005780:Gelatin / Q000494:pharmacology; D020723:Glucuronic Acid / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development*; D010368:Pectins / Q000494:pharmacology; D012474:Salmon / Q000382:microbiology; D017747:Seafood / Q000382:microbiology*; D019354:Sodium Lactate / Q000494:pharmacology; D013213:Starch / Q000494:pharmacology
chemical_list: D000085:Acetates; D000464:Alginates; D006603:Hexuronic Acids; C548838:sodium diacetate; D010368:Pectins; D020723:Glucuronic Acid; D002351:Carrageenan; D005780:Gelatin; D013213:Starch; D019354:Sodium Lactate