Does cooking or vinegar kill Cyclospora? How to avoid the diarrhea-causing parasite, according to health officials

Health officials in Texas and across the country are urging families to practice safe meal-making practices as a summer stomach parasite continues to spread.

The Texas Department of State Health Services (DSHS) reports that as of July 6, the state is seeing 48 cases of Cyclospora that match federal definitions for an outbreak.

The Cyclospora parasite causes a condition called cyclospriasis. The Centers for Disease Control and Prevention (CDC) says the parasite is spread by eating food or drinking beverages that contain it. Common symptoms include diarrhea, loss of appetite, weight loss, cramping, bloating, nausea, and fatigue. In rarer cases, the CDC says, patients may experience vomiting, body aches, headaches, low-grade fevers, and other flu-like symptoms. The agency said symptoms usually develop a week after infection, though it's possible to have cyclosporiasis without symptoms. The CDC also said most people will recover without needing any treatment.

How has the parasite spread before?

In the United States and Canada, Cyclospora outbreaks have been tied to the following foods in the past:

• Bagged salad mixes and kits (i.e., ones with pre-cut lettuce blends that include romaine, iceberg, red cabbage, or carrots in them)
• Fresh cilantro 
• Fresh basil
• Raspberries
• Snow peas
• Green onions

To note, the CDC said there's no evidence of a single outbreak linking all cases.

How can families protect against the parasite?

Health officials say it's important to wash hands with soap and water both before and after handling food. Firm fruits and vegetables, like melons and cucumbers, should be scrubbed with a clean produce brush. It's also advised that you cut away any damaged or bruised areas on fruits and vegetables before preparing and eating.

Utensils and surfaces should also be washed and sanitized before and after food is handled. Display cases and refrigerators used to store produce should also be washed and sanitized, as should cutting boards used for food preparation.

Any cut, peeled, or cooked fruits and vegetables should also be refrigerated as soon as possible.

Are there any more specific tips or tricks to avoid Cyclospora?

The Michigan Department of Health and Human Services shared food-specific guidance to help avoid the parasite, focusing on produce historically affected by Cyclospora outbreaks.

Families should purchase whole heads of lettuce instead of prewashed, bagged lettuce or salad mixes. When preparing the food, remove the outer two or three leaves, then wash the remaining leaves under running water. When possible, cook leafy greens.

If a recipe calls for cilantro or basil, Michigan health officials advise separating the leaves and washing them thoroughly under running water. Similar to lettuce and leafy greens, cooking is the safest option.

If you're using green onions, trim the root end, remove the outer layer, and wash thoroughly under running water. Again, cooking is the safest option.

Snow peas should also be washed thoroughly under running water, with the surface rubbed. Cooking is again the safest option.

Raspberries, Michigan health officials note, have a surface that is difficult to clean. Families are advised to consider using cooked raspberries, such as in jams or pies, or using frozen raspberries. Freezing raspberries may reduce Cyclospora, but it will not eliminate the parasite.

Does vinegar kill Cyclospora?

It doesn't kill it, but it can help remove it. In 2021, researchers in Norway mixed three parts water with one part vinegar to clean raspberries and blueberries of three different parasites, one of which was Cyclospora. 

The mixture removed more parasites from both kinds of berries, but not by a significant amount compared to cleaning the berries in a salad spinner. However, it did help clean the berries more than just running them under water.

Michigan health officials recommend that, when possible, food be heated to 158 degrees to kill the parasite, aligning with guidance to cook food items that have historically been linked to Cyclospora outbreaks.