As part of its enforcement activities, the Food and Drug Administration sends warning letters to entities under its jurisdiction. Some letters are not posted for public view until weeks or months after they are sent. Business owners have 15 days to respond to FDA warning letters. Warning letters often are not issued until a company has been given months or years to correct problems. Generally, portions of the letters are redacted from public view.

The FDA has issued warning letters to three food operations for serious violations including widespread rodent activity in a nut facility, bird droppings contaminating onion packing lines, inadequate allergen controls during roasting, and sanitation failures. The findings highlight risks of filth contamination, allergen cross-contact, and unsafe food entering the market.