Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth ofListeria monocytogeneson Cold Smoked Salmon

Abstract

The relatively high incidence ofListeria monocytogenesin cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population ofL. monocytogenesby a maximum of 3.3 log CFU/cm2(films) and 2.9 log CFU/cm2(coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth ofL. monocytogenesthan their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population ofL. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm2, respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development ofL. monocytogenesand spoilage microflora thus enhancing the safety and quality of CSS.