The Cyclospora parasite needs time (days to weeks) after being passed in a bowel movement to become infectious for another person.
This week's CDC update showed slightly stronger wording.
The number of outbreaks could continue to climb, according to University of Minnesota professor Michael T. Osterholm, a food-borne disease expert who said tracking the outbreaks will be challenging.
Symptoms related to the outbreak began on May 14. They have been recalled. Recalls were issued in June for those four states as well as IL and Indiana. They have a "Best If Enjoyed By" date of June 17, 2018.
Consumers who have purchased the recalled items should not consume them and throw them away immediately. It added: "Most ill people reported buying pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip in the Midwest".
The FDA has not yet identified ingredients linked to the outbreak, saying only that each component is under investigation.
The recalled products were sold in Illinois, Indiana, Iowa, Michigan, Minnesota and Wisconsin, but so far only consumers in four states - Iowa, Michigan, Minnesota and Wisconsin - have reported coming down with the cyclosporiasis infection.
The time between becoming infected and becoming sick is usually about 1 week. Other symptoms can include loss of appetite, weight loss, stomach cramps/pain, bloating, increased gas, nausea, and fatigue. Vomiting, headache, fever, body aches and flu-like symptoms can also occur.