UBC researchers have detected antibiotic-resistant E. coli bacteria on lettuce from several Vancouver farmers’ markets.
Researchers collected samples from 14 vendors at five different, unidentified markets in Vancouver, and tested them for a range of different bacteria. Coliform bacteria was detected in 72 per cent of samples, of which 13 per cent harbored E. coli. Resistance to one or more antibiotics was detected in 97 per cent of the E. coli samples. One-fifth of the E. coli in the samples suggested fecal contamination.
Lead author of the study, Jayde Wood, a former master’s student in the Faculty of Land and Food Systems, stressed that all the samples fell within Health Canada guidelines. But she said the findings warrant further investigation.
“One of the shocking things we noticed was the multi-drug resistant bacteria,” she said. “We need to investigate possible selection pressures along the food chain that may contribute to this phenomenon.“
Jayde Wood
Wood, now a second-year UBC Law student, said she was inspired to conduct the research after observing increased rates of foodborne disease outbreaks related to fresh produce.
“Ten to 20 years ago, outbreaks were mostly related to beef and animal products,” she said. “Things have changed. The proportion of foodborne disease related to fresh produce has experienced a drastic increase in the past 10 years.”
Most people believe that washing produce before consumption can lower the risk of bacterial infection, but Wood said this likely isn’t very effective.
“You can probably wash away a lot of bacteria, but it only takes a tiny amount of pathogen to get you sick,” she explained. “Chances are not that great that washing will completely eliminate all of the virulent bacteria.”
Wood said the best defense is to keep up to date with recalls and warnings issued by the Canadian Food Inspection Agency.
“There’s not too much else you can do as a consumer,” she said. “Cooking is effective at eliminating bacteria, but you don’t really boil your salad before you eat it.”
Microbiological Survey of Locally Grown Lettuce Sold at Farmers’ Markets in Vancouver, British Columbia appears in the January 2015 issue of Journal of Food Protection.
Related article: http://news.ubc.ca/2010/07/01/boiled-salad-anyone/
