Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2013
Publication Date: 7/28/2013
Citation: Wang, R., Kalchayanand, N., Bosilevac, J.M., Arthur, T.M. 2013. Biofilm formation and sanitizer resistance contributes to “High Event” meat contamination by E. coli O157:H7. International Association for Food Protection Proceedings. [abstract] P1-48 Page No.48.
Technical Abstract: Background E. coli O157:H7 is an important foodborne pathogen responsible for numerous outbreaks worldwide. FSIS regulates this pathogen as an adulterant in meat products, and a “High Event Period” is defined as a time period in which commercial meat processing plants experience a higher than usual rate of E. coli O157:H7 in trim samples. Genetic analysis indicated that within a “High Event”, most of the contamination strains belong to a singular dominant O157:H7 strain type. This was in disagreement with the current model of beef contamination stating that the finished product contamination occurs when the incoming pathogen load on the hides, which consists of a diverse strain type, exceeds the in-plant intervention capacity. Thus, we hypothesize that the “High Event” contamination is due to certain in-plant colonized E. coli O157:H7 strains that are better able to survive exposure to sanitizers, possibly through the formation of biofilms. Materials A subset of 47 E. coli O157:H7 strains obtained from “High Event” beef product contamination was compared to a group of 47 E. coli O157:H7 Diversity Control Panel strains, in terms of biofilm forming ability and sanitizer resistance. Biofilm formation was tested on 96-well polystyrene plates for 1 – 6 days. Sanitizer resistance of the mature biofilms was compared between the two sets of the strains using the common sanitizers, including chlorine, Vanquish (quaternary ammonium compounds), and ProOxine. Results No difference in “early stage” biofilm formation was observed between the two sets of the E. coli O157:H7 strains after incubation at room temperature for 1 or 2 days. However, the “High Event” strains overall demonstrated significantly higher potency of “mature” biofilm formation after incubation for 3 – 6 days. In addition, the “High Event” E. coli O157:H7 strains also exhibited stronger resistance to the sanitizer treatments commonly used in commercial meat plants. Conclusions Biofilm formation and high sanitizer resistance may contribute to the “High Event” beef contamination by E. coli O157:H7 in commercial meat processing plants.