Dr D.J.Bolton, Food Safety Department, The National Food Centre, Teagasc, Dunsinea, Castleknock, Dublin 15, UK (e-mail: d.bolton@nfc.teagasc.i.e).


The-survival-characteristics-of-a-non-toxigenic,-antibiotic-resistant-strain-of-Escherichia-coli-O157:H7-in-bovine-faeces-were-investigated.-Faecal-samples-were-inoculated-with 108-9-cfu-g−1-of-the-organism-and-(i)-stored-in-closed-plastic-containers-at-10 °C, (ii) stored in closed plastic containers placed outside or (iii) decanted onto the surface of grazing land. Recovery and enumeration on Sorbitol MacConkey Agar (SMAC) and Tryptic Soya Agar (TSA) revealed that the E. coli O157:H7 numbers in both enclosed samples (i and ii) had decreased by 4·5–5·5 log10 cfu g−1 within 99 d. Numbers in samples decanted onto grassland (iii) decreased by 4·0–5·0 log10 cfu g−1 within 50 d but the organism was still detectable in the surrounding soil for up to 99 d. Persistence of E. coli O157:H7 in bovine faeces and contaminated pastures may therefore be an important factor in the initial infection and re-infection of cattle.