Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2016
Publication Date: 7/31/2016
Citation: Wang, R., King, D.A., Harhay, D.M., Arthur, T.M. 2016. Evaluation of Salmonella biofilm cell transfer from contact surfaces to beef products. [Abstract] International Association for Food Protection. Supp. A(79):102. P1-64.
Interpretive Summary: Non-typhoidal Salmonella enterica are a leading cause of foodborne illness in the U.S. and around the world. Of the greater than 2500 types of Salmonella enterica, serovar Typhimurium is consistently ranked as one of the two leading serovars attributed to salmonellosis, resulting in more than 6000 cases of reported illness each year. The decreasing cost of bacterial whole genome sequencing (WGS) is resulting in a wealth of sequence data of bacterial pathogens. WGS of Salmonella enterica strains is revealing the genetic diversity present in the “family tree” of this group of pathogens. These data have the potential to increase our understanding of what makes Salmonella Typhimurium such a successful pathogen, as well as provide information needed to differentiate members of one branch of the family tree from another. In order to increase our understanding of the genetic diversity of Salmonella Typhimurium associated with cattle and beef, we present here the complete, closed reference genome sequence data for ten Salmonella Typhimurium strains isolated from cattle or human sources.
Technical Abstract: Introduction: Meat contamination by Salmonella enterica is a serious food safety concern. One common transmission route that leads to cross contamination in meat plants is bacteria transfer from biofilms on contact surfaces to meat products via direct contact. Many factors could affect biofilm transfer efficiency, including biofilm forming ability, food product composition and the type of contact surface materials. We evaluated the impact of these factors on Salmonella biofilm cell transfer from common contact surfaces to beef products. We also determined Salmonella prevalence after beef products contacting solid surfaces colonized by Salmonella biofilms. Purpose: To evaluate the effects of biofilm forming ability, meat surface composition and contact surface materials on Salmonella biofilm cell transfer efficiency. Methods: Strains of Salmonella serotypes Anatum and Dublin were used to quantify enumerable amount of bacteria transferred from biofilms on solid surfaces to beef products after direct/brief contact. The effect of direct contact with biofilm-colonized surface on Salmonella prevalence rate in beef products was determined after sample enrichment. Results: Effective transfer of Salmonella cells from biofilms on solid surfaces to beef products via direct contact was observed. Biofilm forming potency had the most significant effect on transfer efficiency. Contact surface materials also affected the transfer as biofilms on stainless steel surface appeared to transfer more efficiently than those on polyvinyl chloride plastic surface. Conversely, meat surface composition (muscle or fat tissues) showed no significant effect on biofilm transfer efficiency. Importantly, after enrichment all beef samples that contacted Salmonella biofilms exhibited positive Salmonella prevalence, including samples with no enumerable transferred Salmonella cells. Significance: These data indicate that Salmonella biofilms, even at low levels, still present a serious risk of causing cross-contamination, thus, highlight the importance of proper sanitization procedures in meat plants.