Not feeling quite right? It might not just be the summertime blues. And this time of year, it’s not likely to be the real flu, either. It’s far more likely to be some kind of food poisoning.

Summer gives us all kinds of opportunities for food poisoning. Leaving potato salad, macaroni salad or cole slaw out just a little too long in the sun can give you salmonella. So can undercooked eggs in egg salad.

Didn’t cook that chicken quite long enough on the grill? The culprit’s probably campylobacter.

Got a bad oyster? E. coli.

To some extent, we can predict these things and avoid them. Keep raw shellfish ice cold; cook chicken to 180 degrees ( and check with a meat thermometer). Put the salads away immediately after use, and keep them covered and cold.

A listeria threat is now underway involving fresh summer fruit, such as peaches, nectarines, and plums from California. The fruit was sold at Hannaford’s, Walmart, Sam’s Club, and Trader Joe’s, among other national chains, after internal testing turned up the bacteria at a packing house in Tulare, California.

No illnesses have yet been reported, but a precautionary recall is underway.

Listeria is a potentially serious illness for specific populations, especially young children and pregnant women, who may suffer stillbirths, miscarriages, or lifethreatening infections of the newborn. Symptoms include headaches, stiff neck, confusion, loss of balance, and convulsions, in addition to fever and muscle aches.

Often, listeria is carried in cheese, but in 2011, an infection of cataloupe killed 33 people and another 10 died from listeria poisoning that wasn’t able to be linked directly to the cantaloupe infection. One woman suffered a miscarriage. The deaths continued until February of 2012.

It took almost two weeks from the time the illness was first reported to the time the company voluntarily recalled the melons.

However, as the inspectors soon discovered, listeria was everywhere in the plant. It was found on equipment used for cutting the melons that had previously been used on a potato farm. It was found in the water that washed the melons in the plant. The melons weren’t pre- cooled before going into cold storage, a necessary step. And a dump truck that took unsaleable melons to a cattle farm might have brought back another strain of the disease.

Unless we grow our own, we can’t possibly know these things until after an outbreak occurs.

But we can get to know our farmers very well.

Buying fresh fruit at farmer’s markets speeds up the pace of investigation if a food-borne illness is determined, because the patient or the family can usually identify the farm the produce came from. That keeps more people from becoming infected, and lessens the chance of a more serious outbreak.

Before you eat any fruit or vegetable, wash the outside completely and keep rinsing your knife. Wrap up large fruits, like melons, and keep them cold between servings.

Don’t let this summer be the year you swear off plums or watermelon because they made you deathly ill.