Salmonella Transfer from Tile,Wood and Carpet to Food

摘要

Bologna,was exposed to either tile,wood or carpet that had been inoculated with Salmonella Typhimurium and held for 0,2,4,8,or 24 hours prior to contact.Contact times of 5,30,and 60 seconds were used for food to tile or carpet after which the bacterial numbers transferred to the food were determined.The inoculum residence time(0-24 hours)had a significant effect on the number surviving cells and the number picked up by the food on both tile and carpet.The surfaces were inoculated with approximately log 7-8 cells/ml and when food was immediately exposed to the tile 7.3 logs cfu/ml were recovered.This steadily deceased as the bacterial residence time increased from 2,4,8,and 24 hours with pick up of cells of 6.5,4.8,4.6,and 3.9 log cfu/ml of rinse solution,respectively.For bologna exposed to tile,there was generally an increase in cells picked up between 5 and the 30 and 60 second exposure times but over 99% of the cells were picked up after 5 seconds of exposure.The exposure of bologna to carpet inoculated with S.Typhimurium followed a similar trend,however,lower cell numbers were recovered and a greater decrease in bacterial cells on bologna after 24 hours of residence time was found.The 0,2,4,8,and 24-hour residence times resulted in 5.4,5.5,5.4,4.1,and 1.8 log cfu/ml rinse,respectively.Bologna exposed to carpet picked up more bacterial cells at 60 and 30 seconds compared to 5 seconds exposure,however these differences were all within 1 log value except for the 24 hour residence time.Additionally,S.Typhimurium survived up to 28 days on tile thus cross contamination of food from contact with surfaces is a food safety concern.