Evaluation of Salmonella biofilm cell transfer from common food contact surfaces to beef products

Authors: Wang, Rong; King, David - Andy; Kalchayanand, Norasak - Nor

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2021
Publication Date: 4/1/2022
Citation: Wang, R., King, D.A., Kalchayanand, N. 2022. Evaluation of Salmonella biofilm cell transfer from common food contact surfaces to beef products. Journal of Food Protection. 85(4):632-638. https://doi.org/10.4315/JFP-21-334.
DOI: https://doi.org/10.4315/JFP-21-334

Interpretive Summary: Beef contamination by Salmonella enterica is a serious public health concern that can cause foodborne outbreaks and significant financial loss due to product recalls. Available evidence indicates that bacterial biofilms, the surface-attached microbial communities, may contribute to meat contamination via bacteria direct transfer from biofilms on contact surfaces to meat products. We studied biofilm transfer of Salmonella strains from stainless steel or polyvinylchloride (P.V.C) surfaces to either lean muscle or fat tissue of beef trim. Our results showed that Salmonella biofilms could be effectively transferred multiple times from contact surfaces to beef products. Salmonella biofilms on stainless steel surfaces appeared to transfer more efficiently to beef trim compared to those on P.V.C surfaces. However, the type of meat surface tissue did not impact biofilm cell transfer. Our study demonstrated the potential of Salmonella biofilms on common contact surfaces to cause cross contamination in meat processing plants.

Technical Abstract: Meat product contamination by Salmonella enterica is a serious public health concern that can result in foodborne outbreaks and significant financial loss due to product recalls. Available studies have suggested that bacterial biofilm formation at processing environment and the contaminated contact surfaces might contribute to meat contamination. Since bacteria transfer from contact surfaces to food products via direct contact has been deemed as the most common transmission route that could lead to cross contamination in food processing environment, we selected Salmonella strains isolated from beef trim to evaluate the effect of biofilm forming ability, contact surface materials, and beef surface tissue types on transferability of Salmonella biofilm cells from common contact surfaces to beef products. Salmonella biofilms developed on stainless steel (S.S) or polyvinylchloride (P.V.C) surface under relevant processing conditions were transferred consecutively via direct contacts of 30 sec each to either lean muscle or adipose tissue surfaces of 15 pieces of beef trim. Our results showed that Salmonella biofilm cells could be effectively transferred multiple times from contact surface to beef products as enumerable Salmonella cells could be detected on most of the meat samples. Bacterial biofilm forming ability had the most significant impact on transfer efficiency as the strong biofilm forming strains not only transferred higher amounts of bacteria to meat products after each contact, but also contaminated more meat samples with enumerable Salmonella cells compared to the weak biofilm formers. Contact surface materials could also affect transferability as Salmonella biofilms on S.S surface appeared to transfer more efficiently to beef trim compared to those on P.V.C surface. Conversely, the two types of meat surface tissues showed no significant difference on biofilm transfer efficiency. Furthermore, biofilm - contacted beef trim without enumerable Salmonella cells all exhibited positive Salmonella prevalence after enrichment, regardless of the strains’ biofilm forming ability and contact surface materials. Our study demonstrated the high potential of Salmonella biofilms on common contact surfaces to cause product cross contamination in meat processing plants.