new report out Friday reveals some leafy greens recently sold at supermarkets were contaminated with a potentially deadly bacteria. Consumer Reports says it tested nearly 284 samples of fresh greens like lettuce, spinach and kale and found six of those samples tainted with listeria.

Consumer Reports says the six contaminated samples included both pre-washed and unbagged greens sold at retailers in Connecticut, New Jersey, and New York in June, including Acme, Costco, Hannaford, and Whole Foods. All of the retailers stress that food safety is a top priority, and public health officials have not reported any illnesses or concerns following their own inspections.

Consumer Reports notes their study is not large enough to draw any conclusions about a specific brand or retailer, but rather is a "snapshot" intended to highlight that more needs to be done to ensure safety.

In a statement to CBS News, a trade association that represents retailers, wholesalers, and suppliers that sell products to grocery stores said, "the incidents outlined in consumer reports … remind us that the entire supply chain has a responsibility for safe food handling."