Evaluation of Potential for Translocation of <i>Listeria monocytogenes</i> from Floor Drains to Food Contact Surfaces in the Surrounding Environment Using <i>Listeria innocua</i> as a Surrogate

Abstract

Floor drains in processing environments harbor Listeria spp. due to continuous presence of humidity and organic substrates. Cleaning and washing activities in food-processing facilities can translocate the bacterial cells from the drain to the surrounding environment, thus contaminating food products still in production. This study evaluated the potential for translocation of Listeria monocytogenes from drains to food contact surfaces in the surrounding environment using Listeria innocua as a surrogate. A 7 × 7 × 8-foot polycarbonate flexi-glass chamber with a 10-inch-diameter drain mounted on an aluminum cabinet was used. Stainless steel coupons (6.4 × 1.9 × 0.1 cm, 12 per height) were hung at 1, 3, and 5 feet inside the chamber. Four treatment sets; non-inoculated, non-treated; non-inoculated, treated; inoculated, treated; inoculated non-treated; and two subtreatments of 8 h and 48 h were performed. For the inoculated sets, meat slurry (10 g of ground beef in 900 mL water) and a four-strain cocktail of Listeria innocua at 7 -8 log CFU/mL were used. For the treated sets, in addition, a commercial cleaner and sanitizer was applied. The drain was cleaned using a pressure hose (40 -50 psi) after 8 h and 48 h. Coupons were then removed and enriched in listeria enrichment broth to establish if any cell translocated from the drain onto the stainless steel coupons via aerosols generated during washing. Confirmation was done using VIP Listeria rapid test kits. Results indicated translocation at all three heights ranging from 2% -25%. Significantly higher translocation (p < 0.05) was found at 1 foot (up to 25%), followed by 3 feet (up to 11%) and 5 feet (up to 2.7%). This research indicated that translocation of Listeria spp. from drains to food contact surfaces does occur and increases with increased proximity to the drain.

Antibacterial Effect of Aluminum Surfaces Untreated and Treated with a Special Anodizing Based on Titanium Oxide Approved for Food Contact

“…The food production chain faces daily challenges concerning microbial contamination, in particular on inert structural surfaces of food contact materials (FCM) such as foils for wrapping foods, containers for convenience foods, lids for yogurt containers, tanks for wine, juices, oil, milk, baking trays, meat and sausage hooks, machine parts and utensils for milk processing, which are generally made of aluminum and might be able to produce environments suitable for microorganisms’ proliferation [ 1 , 2 , 3 , 4 ]. Most of these microorganisms do not adversely affect food quality or safety, whereas others can, although depending upon the present number [ 5 ].…”

A Meta-Analysis of Bacterial Communities in Food Processing Facilities: Driving Forces for Assembly of Core and Accessory Microbiomes across Different Food Commodities

“…Dispersal from these non-food-contact surfaces to food is mediated by factors such as condensation, airflow and drain back-ups. Cleaning and sanitization can contribute to dispersal, e.g., by high-pressure washing that generates aerosols [ 10 , 119 ]. Both allochthones and autochthones are impacted by improvements in the hygienic design of processing facilities and equipment, improved cleaning and sanitization protocols and the improved training of personnel in food safety management.…”

Identification and genotyping of Listeria monocytogenes in the chicken shredding line

“…Microorganisms that reproduce in this way can reach food processing environments by many means and can settle in food processing equipment. Food products produced under these conditions can also be easily contaminated (Saini, ).…”