Modelling the Survival ofEscherichia coliO157:H7 on Raw Portioned Tomatoes, Inoculated withAspergillus fumigatusandEmericella nidulans

Abstract

The metabiotic interactions occurring among two fungi (Aspergillus fumigatus and Emericella nidulans) and Escherichia coli O157:H7 on raw portioned tomatoes were studied. Tomatoes, preinoculated with the moulds and inoculated with the pathogen, were packaged in air and stored at 4, 8 and 12∘C for 9 days; pathogen cell number and pH were monitored throughout the storage and the data were modeled using three different equations (Geeraerd, Weibull, and modified Weibull), to assess the shoulder length, the 1-log reduction time, and the death time. Both A. fumigatus and E. nidulans increased the survival of E. coli O157:H7 through the prolongation of the shoulder length; in contrast, the death time was significantly increased. The results of this paper suggested that the metabiotic interactions aspergilli/E. coli O 157:H7 could be of public concern, as the consumption of tomatoes (or other fruits and vegetables) contaminated both by the moulds and the pathogen is a possible scenario.