Listeria and other unsanitary conditions were found at a Whole Foods plant in Massachusetts earlier this year, the Food and Drug Administration revealed in a warning letter telling the grocery store chain to take immediate action to fix the issues. 

According to the letter, when FDA inspectors visited the plant in February, they observed a number of problematic conditions and practices at the plant — which produces prepared and prepackaged foods for Whole Foods Stores —  including allegedly “serious” violations of the FDA’s Current Good Manufacturing Practice regulations.

Products at the plant, the FDA says, may have been prepared, packed, or held “under insanitary conditions whereby they may have been contaminated with filth or rendered injurious to health.”

Inspectors say they witnessed incidents in which condensation was allowed to potentially drip into ready-to-eat products. For example, ready-to-eat mushroom quesadillas were stored and pesto pasta was mixed directly under an area in a room where condensation from ceiling joints was dripping onto the surface below.

Additionally, the FDA says Whole Foods failed to maintain equipment in acceptable conditions. Inspectors tested 100 swabs of areas where food contact is made, and tests found the presence of non-pathogenic bacteria Listeria welshimeri.

“This finding demonstrates that conditions exist in and on your equipment that would support the presence and growth of Listeria monocytogenes and indicates that your cleaning and sanitation practices may not be adequate,” the letter states.

Other issues included seeing employees spray ammonium sanitizer near an open bunch of salad, an employee’s clothing frequently touching the salad greens during the packaging process, and another worker packaging cartons of quinoa cakes without washing hands or changing gloves.

When it came to actual hand washing the FDA found that the plant lacked running water of a suitable temperature as required under the law.

“Your employees returning from break and other non-food related tasks continued to use this tagged ‘out of service, no hot water, 2/16/16’ hand washing sink before returning to preparing and handling ready-to-eat foods,” the letter states.

According to the letter, Whole Foods responded to the inspection findings by noting that leadership takes the observations seriously and it would retrain employees on safety precautions.

However, the FDA found these responses to be unacceptable.

“We do not consider your response acceptable because you failed to provide documentation for our review, which demonstrates that all your noted corrective actions have been effectively implemented,” the letter states.

Whole Foods has 15 days from receipt of the warning letter to provide FDA with documentation of corrective actions.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.