The outbreak started in May. The FDA reported an additional 109 cases on Thursday.
RELATED: Health alert issued for salads, wraps from Trader Joe's, Walgreens, Kroger due to parasite worry
[Ads /]
At least 16 people have been hospitalized due to the cyclospora parasite, which causes intestinal illness.
Symptoms of the illness include diarrhea, vomiting, fever and body aches.
The illness can last anywhere from several days to a few months and can be treated with antibiotics.
[Ads /]
An unused package of Fresh Express salad mix, which is used to make McDonald's salads, tested positive for cyclospora, according to the FDA.
In July, McDonald's said it had removed the mix from impacted restaurants.
In a statement, Fresh Express said it issued a "precautionary recall" on July 27.
Click here for the latest from the FDA about this outbreak.