Norway tests flour for STEC

Norwegian surveillance has found a low level of flour samples positive for Shiga toxin-producing E. coli (STEC). The Norwegian Food Safety Authority (Mattilsynet) commissioned a survey of STEC in wheat flour to gather data on the problem. A total of 151 samples of flour were collected from retailers in 2021 and analyzed in 2022. Enriched samples were examined for the presence of selected genetic markers. Attempts to isolate STEC were carried out from samples that were positive for Shiga toxin (stx) 1 and/or stx2. Isolates identified as STEC were further characterized using whole genome sequencing. STEC was isolated from three samples. They were identified as STEC O187:H28, O155:H21, and O154:H31 and none of the isolates harbored the eae gene. There is not much literature on how flour is contaminated and about its microbiological quality, although some studies have been done. Results showed that the occurrence of STEC in flour on the Norwegian market was low. Although STEC was ...