Occurrence and survival of verocytotoxin-producing Escherichia coli O157 in meats obtained from retail outlets in the Netherlands

In 1996 and 1997, 2,941 fresh and processed meat products obtained from sup ermarkets and butcher shops in The Netherlands were examined for the presen ce of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC ). Additionally, the fate of O157 VTEC in raw meat products stored at low t emperatures and the effect of different additives were evaluated. O157 VTEC strains were isolated from 6 (1.1%) of 571 samples of raw minced beef, 2 ( 0.5%) of 402 samples of raw minced mixed beef and pork, 1 (1.3%) of 76 samp les of raw minced pork, 1 (0.3%) of 393 samples of other raw pork products, and 1 (0.3%) of 328 samples of cooked or fermented ready-to-eat meats. Oth er raw beef products (n = 223) and meat samples originating from poultry (n = 819), sheep or lamb (n = 46), or wild animals (n = 83) were all found to be negative for O157 VTEC. For the survival experiments we used tartaar (m inced beef with a fat content of less than 10%) and filet americain (tartaa r mixed with a mayonnaise-based sauce [80 to 20%]). The O157 VTEC strain te sted was able to survive in tartaar and filet americain stored at -20, 0, 5 , or 7 degrees C for 3 days. At both 7 and at 15 degrees C, O157 VTEC count s in tartaar and filet americain remained virtually unchanged throughout a storage period of 5 days. Addition of acetic acid (to pH 4.0), sodium lacta te (1 and 2% [wt/wt]), or components of the lactoperoxidase-thiocyanate-hyd rogen peroxide system to filet americain did not result in a reduction of v iable O157 VTEC cells during storage at 7 or 15 degrees C. It was concluded that raw meat contaminated with O157 VTEC will remain a hazard even if the meat is held at low or freezing temperatures.