When folks get sick after a picnic, people often blame the potato salad. Or the chicken salad. Or whatever other side dish was made with mayonnaise. But that’s usually not the culprit.
“It’s not always the potato salad…except when it’s the potato salad,” says Ben Chapman, a food safety researcher at NC State University. “There are lots of other foods at a cookout that can also lead to illnesses.”
When it is the potato salad, the culprits are usually Staphylococcus aureus or Clostridium perfringens. And a combination of factors can lead to problems. In most “salads” of this type, low-acid potatoes, chicken, pasta or hard-boiled eggs are added to the mayonnaise. The mayonnaise is acidified to make it safe, but the low acidity of the potatoes (or foods) offsets the acidity of the mayonnaise, creating an environment where bacteria can thrive.
That sets the stage. Then poor hygiene comes into play. S. aureus, for example, can often be found on our faces, particularly around the eyes or nose. So, S. aureus can be introduced to salads when people touch their face and then – without washing their hands – touch the food.
Originally posted May 24, 2018. Written by Matthew Shipman. Photo credit: Stacy Spensley. Shared under a Creative Commons license.