Memorial Day weekend is the official kickoff for summer, and as the weather heats up, so do the number of meals that will be served outside.

Whether served to friends poolside or family in a backyard cookout, food should be kept in certain conditions to avoid foodborne illness, the U.S. Department of Agriculture’s Food Safety and Inspection Service advised in a news release.

“The bacteria that cause foodborne illness love the summertime as much as we do because they thrive and multiply quickly in warmer temperatures. This causes illnesses to spike during the summer,” Under Secretary for Food Safety Dr. Emilio Esteban said.

With that in mind, the USDA’s Food Safety and Inspection Service offers these tips —

— Wash hands: The first step to serving summer foods safely is to start with clean hands. If running water is available, wet hands, lather with soap, scrub for 20 seconds, rinse and dry. If no running water is available, use hand sanitizer or moist towelettes that contain at least 60% alcohol.

— Pack perishables safely: When traveling with perishable food to places like the pool, beach, summer camp, hiking or a cookout, always use cold sources in coolers or insulated containers to keep food below 40 degrees Fahrenheit. Cold source options include ice, frozen gel packs and frozen beverages that do not require refrigeration for safety, such as water bottles, iced tea and juices like apple and grape.

— Additional cooler tips: Pack beverages in one cooler and perishable food in another cooler, as the beverage cooler may be opened frequently, causing the temperature inside the cooler to fluctuate and become unsafe for perishable foods; keep coolers and insulated bags out of the sun; full coolers or insulated bags will keep your perishable foods cold and safe for much longer than half-full ones; and place an appliance thermometer — one traditionally used for the refrigerator or freezer — in the cooler to be sure the food stays at 40 F or lower.

— Keep out of the Danger Zone: The Danger Zone is the temperature range where bacteria multiply rapidly between 40 and 140 F. Perishable foods, including meat and poultry, sliced fruits and vegetables and cooked side dishes, should avoid the Danger Zone or be kept hot or cold to maintain food safety. Cold foods must be kept at 40 F or below by placing them in the refrigerator, coolers, insulated containers or nestled over ice. Hot foods must be kept over 140 F by placing them on the grill, in heated chafing dishes, slow cooker or warming trays. Check the temperatures of cold and hot items frequently.

— Follow the “two-hour rule”: Foods that are kept hot or cold out of the Danger Zone or do not sit out for more than two hours — one hour if over 90 F — are safe to keep. Any other items should be considered unsafe and need to be discarded. When in doubt, throw it out.