Seventy percent of supermarket chickens in the United Kingdom have tested positive for Campylobacter in the first half of a year-long study being conducted by the country’s Food Standards Agency (FSA). In recent years, FSA has said its number-one food safety priority is to reduce contamination of Campylobacter, a foodborne bacteria largely associated with chicken that causes diarrhea, vomiting, and abdominal cramping. As part of that effort, the agency plans to test 4,000 supermarket chickens for Campylobacter over the course of a year. Now halfway through, they’ve tested 1,995 chickens and their packages. Eighteen percent of chickens tested above the highest category of contamination levels (more than 1,000 colony-forming units per gram), while six percent of packages also tested positive for Campylobacter. While the levels of contamination varied between retailers, no store has yet to meet targets for reducing Campylobacter levels. According to FSA, Campylobacter is the most common form of food poisoning in the UK, sickening roughly 280,000 people a year. In the U.S., Campylobacter is estimated to cause 1.3 million illnesses each year. Earlier this week, major U.K. retailer Marks & Spencer announced its “Campylobacter challenge,” a 5-point program intended to reduce levels of illnesses contracted from its chicken. Strategies outlined in the plan include rapidly chilling chickens as they’re processed and offering bonuses to farmers who produce chickens on Campylobacter-free farms. In 2011, food safety law firm Marler Clark funded a bacterial survey of retail chicken sold in the Seattle area, finding that 65 percent was contaminated with Campylobacter. (Marler Clark underwrites Food Safety News.) Additionally, 42 percent of chicken in that survey was contaminated with Staphylococcus aureus. In total, 80 percent of chicken samples were found to harbor some potentially harmful pathogen.