Inhibition of Microbial Growth in English Sole (Parophrys retulus)1

Abstract

The influence of potassium sorbate on growth of microorganisms in seafood was tested by treating English sole (Parophrys retulus) homogenate with 0, 0.1 and 1.0% potassium sorbate. Viable counts during 1.1-C storage revealed that 0.1% potassium sorbate delayed the onset of logarithmic growth of bacteria for 1 day compared to no delay for the untreated control. The generation time of 1.7 days and a maximum growth level of 109 cells per g were unchanged by the presence of 0.1% potassium sorbate. The 1.0% sorbate treatment extended the lag period to 6 days. The generation time was increased to 2.1 days and the maximum level of growth reached was 107 cells per g on the 14th day. Tests of the microbial flora of the fish revealed that Pseudomonas spp., which comprised 17.1 %of the total at 0 day, increased to 96.0% of the microbial population in 14 days at 1.1 C for the untreated sample. During the same period the Pseudomonas population reached 100% for the 0.1% sorbate-treated sample, and to 98.2% for the 1.0% sorbate-treated sample. Potassium sorbate at the concentrations employed, therefore, did not seem to alter the typical microbial spoilage pattern.