Archives

Page No. : 103–112

ABSTRACT

Foods, either of animal origin or contaminated with animal excreta, have been frequently implicated as the source of Vero toxic Escherichia coli (VTEC). With a view to tackle such contamination in foods, the present investigation was undertaken to study the inhibitory potential of some food-grade preservatives namely, 0.1% sodium benzoate (SB) and 0.1% potassium sorbate (PS), as well as their combination on VTEC O111 that were artificially inoculated in simulating media for beef gravies (pH 7.0 and 5.4) stored at 4°C and −20°C for 45 days, and at 37°C for 48 hours.
During storage of the beef gravy (pH 7.0) at 4°C, SB caused a significant (P < 0.05) inhibition of VTEC whereas PS caused only a slight reduction in their number by the 10th day of storage. The combination of these two preservatives exerted maximum inhibitory effect on VTEC as early as the 8th day. At a lower pH (5.4) at 37°C, SB either alone or in combination with PS caused only a slight inhibition of VTEC as compared to the positive control. At −20°C storage, VTEC in beef gravies (pH 7.0 and 5.4) were significantly inhibited by SB alone or its combination with PS. In general, SB alone or in combination with PS exerted maximum inhibitory effect on VTEC in beef gravy.

Keywords: Vero toxic, E. coli, VTEC, VTEC survivability, Preservatives