SANJAY CHHIBBER, SONIA B BHARDWAJ AND PREETI AGHI
Abstract
Most of the outbreaks of hemorrhagic colitis have been related with the consumption of undercooked ground beef or raw milk. Outbreaks involving acidic foods (apple cider, dry fermented sausage and mayonnaise) due to E.coli 0157:H7 have already been reported. But no attempt has been made to look for its prevalence in different Indian foods having low pH. The study was planned to ascertain the incidence of enterohemorrhagic E.coli in different foods being sold in the market. Samples of foods like mango chatni, lemonade, Imli pani, ladoo etc were taken and processed according to standard methods. Sixteen strains of E.coli were isolated and their serotype profile and ability to grow at an acidic pH was determined. The predominant E.coli serotype was 02 (18.75%) followed by 018,050 and 0158 (12.50%) each. However, no enterohemorrhagic E. coli belonging to serotype 0157:H7 was isolated. Acid tolerance studies on acid adapted and non acid adapted strains of enterohemorrhagic E. coli, enteroaggregative E. coli, faecal E. coli and E. coli isolated from urinary tract was evaluated by growing them in foods like yoghurt, sweet lime juice and mango drink. The results showed better survival of acid adapted enterohemorrhagic E. coli as compared to other strains of E. coli.