Effect of the food additives sodium citrate and disodium phosphate on Shiga toxin-producing Escherichia coli and production of stx-phages and Shiga toxin.

LENZI, LUCAS J.; LUCCHESI, PAULA M. A.; MEDICO, LUCÍA; BURGÁN, JULIA; KRÜGER ALEJANDRA

Frontiers in Microbiology

Lausanne, Frontiers Media

Año: 2016 vol. 7

Induction and propagation of bacteriophages along the food production chain can represent a significant risk when bacteriophagescarry genes for potent toxins. The aim of this study was to evaluate the effect of different compounds used in the food industry onthe growth of Shiga toxin-producing Escherichia coli (STEC) and the production of stx-phage particles and Shiga toxin. We testedthe in vitro effect of lactic acid, acetic acid, citric acid, disodium phosphate, and sodium citrate on STEC growth. A bacteriostaticeffect was observed in most of treated cultures. The exceptions were those treated with sodium citrate and disodium phosphatein which similar growth curves to the untreated control were observed, but with reduced OD600 values. Evaluation of phageproduction by plaque-based assays showed that cultures treated with sodium citrate and disodium phosphate released phages insimilar o lower levels than untreated cultures. However, semi-quantification of Stx revealed higher levels of extracellular Stx inSTEC cultures treated with 2.5% sodium citrate than in untreated cultures. Our results reinforce the importance to evaluate ifadditives and other treatments used to decrease bacterial contamination in food induce stx-phage and Stx production