The retailer said Saturday there have been no confirmed illnesses associated with the items, which are sold under its Marketside store brand at select locations. 

A Walmart spokeswoman said there’s no indication that products sold in its stores are affected by the current cyclospora investigations, but that the company has removed four products as a precaution after receiving notice from a supplier.

Recalls are broadening to reach some US retail stores, where many shoppers have stayed away from buying berries and leafy greens in recent weeks. Produce represents an especially important slice of sales for companies in the summer, as people celebrate holidays and spend more time outdoors. Product removals can typically dampen consumer demand for weeks to months.  

The move comes after Taylor Farms pulled products from a Mexico farm that were sent to 27 states.  

Mexico pledged to investigate the origins of the parasite outbreak, while playing down the idea that contamination occurred in its territory. 

Mexico’s government is working with the US Food and Drug Administration in an “ongoing” investigation to determine “the source” of the outbreak in the US, the Health Ministry in a statement on Saturday. Research institutions from the Health and Agriculture ministries are helping the FDA with a “continuous exchange of technical information” to mitigate health risks and protect populations in both countries.

“Identifying the product’s country of origin provides a traceability data point, but it does not in itself confirm that the contamination occurred within Mexican territory,” the government added.

Cyclosporiasis, a gastrointestinal disease caused by ingesting a microscopic parasite, has infected people in the US across 34 states, according to the US Centers for Disease Control and Prevention. Michigan, the state with the highest case count, has recorded more than 5,000 illnesses as of July 17. State counts typically lag behind national numbers. 

The disease causes severe diarrhea and nausea for a few days or up to a couple months. Symptoms appear up to two weeks after someone has ingested the parasite, making it challenging for federal health authorities to trace back to a source. 

Earlier this week, health officials said a lettuce supplier to Taco Bell locations in the Midwest was the source of most infections. 

Taylor Farms said Friday that no other products are affected and that its branded salad kits sold in supermarkets didn’t contain iceberg lettuce. The company said Saturday it was recalling all iceberg lettuce because it had the “potential to be contaminated with Cyclospora.” 

“We are actively removing the implicated products,” the company said, adding that it had stopped receiving product from the implicated lot, suspended distribution of the iceberg lettuce from Central Mexico, notified customers, and was continuing to work with the FDA, CDC and state authorities.

The shredded iceberg product was distributed June 29 through July 16.

The FDA said Friday that more states could be added to the recall notice. 

Taylor Farms didn’t immediately respond to a request for comment.