WATERFORD — A Camden County public school district celebrating teacher appreciation week wound up with an unwanted shared experience — a foodborne illness, according to the superintendent.

More than 60% of staff members who attended a luncheon on Thursday that was catered by an outside vendor became ill, Superintendent Brenda Harring said in a letter to the school community.

The spate of sickness forced the district's three schools of roughly 900 pre-kindergarten through sixth graders, to switch to at-home learning on Monday.

Camden County health officials then advised that due to the highly contagious nature of such illness, the school buildings should undergo thorough cleaning, Harring continued, so at-home learning would continue for two weeks.

Waterford's two elementary schools and early learning center would reopen on May 24.

Harring noted the "problematic" impact of such an upheaval to the schedule but added the "top priority is always the health and well-being of our staff and students."

Take a Dip In The Most Breathtaking Backyard Pools in New Jersey

LOOK: Here Are 30 Foods That Are Poisonous to Dogs

To prepare yourself for a potential incident, always keep your vet's phone number handy, along with an after-hours clinic you can call in an emergency. The ASPCA Animal Poison Control Center also has a hotline you can call at (888) 426-4435 for advice.

Even with all of these resources, however, the best cure for food poisoning is preventing it in the first place. To give you an idea of what human foods can be dangerous, Stacker has put together a slideshow of 30 common foods to avoid. Take a look to see if there are any that surprise you.