Foodborne bacteria are typically present at very low concentrations in food. This study describes a quick and simple method for concentrating E. coli O157:H7 present in lettuce and cabbage, without microbial enrichment culture. This method involved reducing the extraction buffer and DNA elution volumes. The extraction buffer volume was adjusted to 225, 100, 50, 25, and 12.5 mL to isolate E. coli O157:H7 from 25 g of lettuce or cabbage. DNA was concentrated and compared using real-time PCR. When using 12.5 mL of buffer, < 4 CFU/g of E. coli O157:H7 could be detected within 2 h without enrichment. This result is 100-fold sensitive than pretreatment with of the conventional method using 225 mL. It is suggested that this method could contribute to the prevention of food poisoning accidents in institutional catering settings, such as schools or military facilities, by the rapid and sensitive detection of pathogens without special equipment prior to food consumption stages.
Keywords: 2 h; E. coli O157:H7; Preconcentration; Rapid detection; Without enrichment.
© The Korean Society of Food Science and Technology 2020.