Occurrence of thermotolerant campylobacters in fresh vegetables sold at farmers' outdoor markets and supermarkets.

A total of 1564 fresh samples of 10 vegetable types from two different retail levels (533 samples from farmers' outdoor markets and 1031 samples from supermarkets) were surveyed for the occurrence of thermotolerant campylobacters. In samples from the outdoor markets, campylobacters were detected on six types of vegetables; the detection rates were spinach, 3.3; lettuce, 3.1; radish, 2.7; green onions, 2.5; parsley, 2.4; and potatoes, 1.6%. Campylobacter jejuni was the predominant species (88%), with the remainder being C. lari (8%) and C. coli (4%). When the outdoor market samples were thoroughly washed with chlorinated water, all were negative for campylobacters. Of the samples from supermarkets, all were negative for campylobacters whether purchased in summer or winter. These results suggest that vegetables sold at farmers' outdoor markets are produced and (or) stored under less sanitary conditions than those sold at supermarkets, and they could constitute health hazards. Therefore, vegetables (e.g., potatoes and spinach) from farmers' markets must be decontaminated by washing with chlorinated water or cooked thoroughly before consumption.