Photo

That chicken you bought at the farmers’ market may not be as healthful as you thought.

Researchers in Pennsylvania bought 100 whole chickens from grocery stores, half of which were organic, and 100 from farmers’ markets and tested them for the presence of Salmonella and Campylobacter, two species of bacteria that can cause food poisoning. The study appeared online last month in The Journal of Food Safety.

Among the grocery store chickens, 28 percent of the organic chickens tested positive for Campylobacter and 20 percent for Salmonella, while 52 percent of the nonorganic chickens were contaminated with Campylobacter and 8 percent with Salmonella. But the chickens from farmers’ markets were the most contaminated of all: 28 percent tested positive for Salmonella and 90 percent for Campylobacter.

Poultry farmers who process fewer than 20,000 birds a year are not subject to Department of Agriculture inspections, which may account for some of the differences.

Joshua Scheinberg, a doctoral student at Penn State who led the study, said he did not want to discourage people from shopping at farmers’ markets. But he said both sellers and buyers “have to make sure they’re handling the products properly, keeping them cold, making sure they’re not cross-contaminating tabletops or kitchen implements. Yes, we found in a small study higher levels of these pathogens. But these would be destroyed if properly cooked to 165 degrees.”