Microbial characterization of lightly processed kiwifruit and fruit based salads in relation to packaging atmosphere

Abstract

In this work the effect of two different modified atmospheres on the growth of naturally occurring microorganisms was evaluated, in kiwifruit and in fruit based salads composed by Granny Smith apples, kiwifruits, peaches and strawberries. The stability time of the samples was modelled in order to check the effect of atmosphere packaging and to assess the most relevant microbial indices for the product quality. The obtained results showed that the stability time of the different products was strongly affected by atmosphere; in fact, packaging in both modified atmospheres, seemed to be able to prolong the stability time relatively to mesophilic and psychrotrophic bacteria and yeasts. Nevertheless, the efficacy in prolonging the stability time of the modified atmospheres was lower in fruit based salads than in kiwifruit samples. The packaging in modified atmospheres during storage resulted in a homogenous bacterial population being constituted mainly by gram-negative bacteria, whereas Rhodotorula glutinis, Cryptococcus laurentii and Candida spp. were the most commonly occurring yeasts in kiwifruit samples and Kloeckera spp. was the only yeast species isolated from fruit based salads.