Antimicrobial Capacity of a Cauliflower By-Product Infusion Combined with the PEF Treatment against S. Typhimurium

Abstract

Salmonella spp is a foodborne pathogen related with food outbreaks worldwide. To control it, new strategies have been developed to preserve food products, such as the application of non-thermal treatments like pulsed electric fields (PEF) or the addition of antimicrobial compounds from vegetable by-products. The main objective of this study is to evaluate the antimicrobial effect of PEF treatment, combined with several concentrations of cauliflower by-product infusion against S. Typhimurium.

Survival curves of S. Typhimurium, treated and nontreated by PEF, were obtained during their incubation under different cauliflower by-product infusion concentrations (1%, 5%, 10%) at 37°C. The control sample was incubated with buffered peptone water (0.1%). PEF treatment (20 kV/cm - 900 μs) reduced 4,5 log cycles of the initial microbial population (108 cfu/mL). Also, both in PEF treated and nontreated samples, cauliflower by-product concentrations of 5% and 10% exerted a bactericidal effect against S. Typhimurium, although the time necessary for total inactivation was shorter when combined with PEF (2 hours) than non-PEF treated samples (8 hours).

The results obtained were fitted to a Weibull distribution function, and its kinetic parameters (b and n) were obtained. Both in PEF treated and non-treated samples, b values, which are related with the inactivation rates, were higher when the cauliflower by-product infusion concentration was greater. Also, the b values of PEF treated samples were higher than the b values of non-treated samples. Therefore, the PEF treatment combined with the addition of cauliflower by-product infusion exerted a higher antimicrobial effect against S. Typhimurium than when they were applied separately.

In conclusion, PEF treatment combined with the addition of 5 or 10% of cauliflower by-product infusion could be used as a S. Typhimurium control measure in liquid food products in the future.