Don’t bring last year’s open bottle of ketchup to this summer’s barbecue — unless you want to invite food poisoning, too.

How do you know if the red stuff, or any other condiment on your refrigerator door, is still good?

Many popular burger and hotdog toppers are “relatively low-risk” for a year or more if they’re sealed, says Shelley Feist, executive director of the Partnership for Food Safety Education, a nonprofit coalition of safety experts from the food industry, nutrition associations and the government. Because these products contain preservatives, have a high acid content, or both, they’re “shelf stable,” allowing them to sit in the supermarket for an extended period.

But once you open the container, the clock starts.

Related: Food Safety Fails

Recommended storage times for condiments vary widely, according to the U.S. Department of Agriculture (USDA) and the Food Marketing Institute (FMI). They range from several days for fresh (refrigerated) salsa, guacamole and hummus to at least a year for mustard, the longevity champ.

You can’t rely on those confusing “sell by,” “use by” and “best by” labels set by manufacturers and stores; they’re designed to indicate when foods will lose quality, not spoil. Still, the USDA suggests using the “sell by” date when shopping and “use or freeze” or “best by” dates after products are open.

Related: 5 Mistakes You’re Making With Chicken and Meat

Here are six other steps you can take to make it safer to slather the mustard, relish and other seasonings on your hotdogs and burgers.

Read and heed the storage instructions when you open a container. Most condiments, including ketchup (despite what your local diner thinks), should be refrigerated.

Follow the storage times recommended by USDA and FMI: 

  • Barbecue sauce: 4 months
  • Chutney: 1-2 months
  • Guacamole: 5-7 days
  • Horseradish: 3-4 months
  • Hummus: 1 week without preservatives; 2 months with preservatives, 3 months if pasteurized
  • Ketchup: 6 months
  • Mayonnaise: 1-2 months (for best quality)
  • Mustard:1 year
  • Olives: 2 weeks
  • Pickles and pickle relishes: 2 weeks
  • Salsa: fresh, 3-5 days; bottled, 1 month

You can check times for other foods on FMI’s FoodKeeper database, also available as a free app for Android and Apple phones.

Put ‘em on ice. Don’t let condiments bask in the hot sun. Pack them in a cooler with ice, just as you would other food. If the temperature outside is less than 90 degrees F, they can stay on the picnic table for up to 2 hours; if it’s hotter, 1 hour.

Related: How to Pack A Cooler (So No One Gets Sick)

Check for bulging lids when you buy fresh salsa or hummus just as you’d do for other foods.

Use up the fresh stuff fast. If you’re not planning to consume fresh salsa, guacamole or hummus within a few days, shop for pasteurized hummus and consider buying hummus, salsa and guacamole brands that contain preservatives.

If your power fails, foodsafety.gov recommends you throw out open jars of mayo, tartar sauce and horseradish that have been stored at 50 degrees or higher for over 8 hours.

Condiment recalls

Condiments are subject to contamination during the manufacturing process, just as other foods are. The FDA has reported voluntary recalls by manufacturers for at least two condiments so far in 2015: salsa, recalled for potential bacterial contamination, and hummus, recalled for possible contamination by listeria, a deadly food pathogen that can flourish despite refrigeration.

Related: Food Recalls: What You Need to Know to Stay Safe

Lynn Langway is a prize-winning writer and former editor at Newsweek and the Ladies’ Home Journal. Her articles about health, travel and the environment have appeared in the New York Times, Newsweek, The Nation and numerous websites.