Aims: To investigate the main effects and interactions of different factors : divercin V41 (0-4 ng ml(-1)), NaCl content (0.5-5.5% w v(-1)), phenol (liquid smoke) concentration (0-8 ppm), and pH (5.5-7.5) on Listeria monocytogenes ScottA growth.
Methods and results: Experiments were carried out in BHI broth using a central composite design. Divercin V41 (div41), NaCl content and pH were found to be the most influential factors whereas phenol concentration in liquid smoke had no effect on L. monocytogenes ScottA growth in our experimental domain. The combined effects of div41, NaCl content and pH decreased L. monocytogenes ScottA maximum specific growth rate (mu(max)) from 0.34 to 0.01 h(-1) and led to a significant increase in lag time (t(lag)) from 5.5 to 25 h.
Conclusion: In this study, NaCl, pH and phenol conditions were similar to those currently observed in smoked salmon production. This shows that L. monocytogenes ScottA growth could be efficiently delayed by the use of div41 in addition to the usual technological hurdles.
Significance and impact of the study: In conclusion, the technological hurdles of cold smoked salmon production could be further optimized and combined with the use of div41 or the div41 producer strain to improve the food safety of the product.