Imported edible leaves collected at retail sale in England during 2017 with an emphasis on betel and curry leaves: microbiological quality with respect to Salmonella, Shiga-toxin-producing E.coli (STEC) and levels of Escherichia coli.

Abstract

To investigate the microbiological quality of imported fresh leaves on retail sale during 2017 with respect to Salmonella, Shiga-toxin-producing Escherichia coli (STEC) and levels of E.coli. Two hundred and seventy-nine samples of imported edible leaves (69 banana, 77 betel, 118 curry and 15 other types) were tested. Salmonella spp. were confirmed by whole-genome sequencing and isolated from 44 samples, 26% from curry leaves, 14% from betel and 2·4% from all other leaf types: 80% of all samples contained ≥102 , 44% ≥103 and 22% ≥104 CFU of E.coli CFU per g. All samples where Salmonella were detected also yielded ≥20 CFU of E.coli/g. 54 samples were tested for STEC which was detected in six samples and isolated from three: one was identified as STEC O157:H7. This report further highlights an ongoing problem of Salmonella contamination of imported fresh edible leaves. Among all food tested by Public Health England (approximately 11000 per annum), curry leaves were the herb most commonly contaminated with Salmonella, and betel leaves were the most commonly contaminated ready-to-eat food. The high proportion with unsatisfactory E.coli levels and the detection of STEC suggests risks of contamination by multiple enteric pathogens.