Use of antimicrobial films and edible coatings incorporating chemical and biological preservatives to control growth of Listeria monocytogenes on cold smoked salmon.

Hudaa Neetoo,Fawzi Mahomoodally

doi:10.1155/2014/534915

Abstract

The relatively high incidence of Listeria monocytogenes in 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 of L. monocytogenes by 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 of L. monocytogenes than their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population of L. 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 of L. monocytogenes and spoilage microflora thus enhancing the safety and quality of CSS.

Highlights

Listeria monocytogenes has long been established as an important food-borne pathogen with a fatality rate of 25– 30% [1]
The fate of L. monocytogenes on cold smoked salmon (CSS) slices treated with different binary combinations of antimicrobials in films and coatings is represented in Figures 1(a) and 1(b), respectively
Cold smoked salmon (CSS) is considered a high-risk food because the temperature used during the cold smoking operation is not lethal to L. monocytogenes

Summary

Introduction

Listeria monocytogenes has long been established as an important food-borne pathogen with a fatality rate of 25– 30% [1]. L. monocytogenes infection has been associated with consuming a variety of meat, poultry, fish, and dairy products [3] The prevalence of this organism in cold smoked fish in particular is relatively high and typically between 10 to 40% [4, 5]. Processing of cold smoked salmon (CSS) includes no recognizable critical control point for L. monocytogenes and this product cannot be completely free of this pathogen [7]. For this reason, smoked seafood, including CSS, has been categorized as having a high risk of listeriosis [7]

Objectives

Methods

Results

Conclusion