Swedish Study Finds STEC in 13 Percent of Imported Beef

Shiga toxin-producing E. coli (STEC) has been detected in 13 percent of beef samples tested from meat imported to Sweden between 2010 and 2011.  The country’s National Food Agency tested both beef and leafy greens to obtain data that will help assess the public health risk of STEC in food and could help in developing strategies to deal with the risks.  They collected fresh or frozen samples of minced or whole meat from cattle from the most common countries or regions exporting beef to Sweden between 2010 and 2011. The leafy greens were both domestic and imported products available on the Swedish market from 2012 to 2013. Samples were collected at retail stores, importers, outlets and in markets.  STEC was isolated from 13 percent of the 177 imported beef samples tested. Approximately 3 percent of the samples contained STEC positive for the virulence genes stx2 and eae, both of which are important markers for the ability of the bacteria to cause severe disease.  The pathogens isolated belonged to 14 different serogroups, with STEC O26 being the most common, and STEC O157, frequently implicated in STEC-related foodborne outbreaks in Sweden, found in only two samples.  Only 11 of the 630 leafy greens samples tested positive for stx1 and/or stx2, but no bacteria were isolated.