Here in the USA, the 4th of July—our Independence Day—is the major holiday of the summer, and like celebrations of independence in many other countries, it is filled with festivities such as parades, parties, and fireworks. And while there are a myriad of health-related concerns—including heat; water; and of course, fireworks safety—foodborne illnesses (commonly referred to as “food poisoning”) are a major concern that are often overlooked until it is too late. Outbreak Observatory has covered holiday-related foodborne illnesses before, but this week we will take a quick look at common summertime foodborne illness threats and food safety tips.

It’s (not) Always the Potato Salad

It is not uncommon that picnics and other outdoor get-togethers are the source of foodborne outbreaks, particularly in warmer months. Potato salad always seems to get blamed for causing foodborne illnesses, but it is far from the only source. Historically, the likely culprit in potato salad, or other deli-style salads like chicken or tuna salad, was the mayonnaise. Made from eggs, it was particularly vulnerable to bacterial growth, especially in the days when it was homemade. Modern, commercially available mayonnaise is unlikely to be the source of illness-causing bacteria, and in fact, the other ingredients in potato salad are more likely to be responsible for a foodborne outbreak. Diced vegetables or minced herbs may harbor bacteria and provide ideal surfaces for bacterial growth, and mayonnaise is generally not acidic enough to inhibit bacterial growth. Other sources of foodborne illness include undercooked meat and cross-contamination (eg, contaminating vegetables with uncooked meat). Perhaps the biggest problem, particularly in the summer, is allowing food to sit at room temperature for too long, which can lead to rapid bacterial growth in almost any food that can lead to foodborne illnesses. But, honestly, it’s probably the potato salad.

Food Safety

If you’re like me, your 4th of July might start with a raucous screening of Top Gun to raise your patriotic spirits. And I’m clearly not the only one, as the US Department of Agriculture (USDA) provides guidance on keeping food out of the “Danger Zone.” Failing to properly maintain the temperature of food can allow bacteria, including Salmonella and E. coli, to flourish, and experts recommend keeping food chilled below 40°F (4.4°C) or heated above 140°F (60°C) to prevent rapid bacterial growth. The USDA specifically warns against letting food sit at room temperature for prolonged periods; refrigerated food should not be left out for more than 2 hours, and not more than 1 hour if the ambient temperature is 90°F (32.2°C) or higher.

In addition to storage temperature, some foods must also be cooked to a certain internal temperature to ensure that common bacteria or parasites are killed prior to consumption. If you are firing up the grill for chicken wings, barbeque chicken, or other poultry, ensure that the meat reaches an internal temperature of at least 165°F (73.9°C). If you are doing beef (eg, cheeseburgers or steaks) or pork (eg, ribs or pulled pork) the temperature needs to reach at least 145°F (62.8°). Contrary to popular belief, checking the temperature of meat by looking at the color or by poking it with your finger are not a reliable ways to gauge doneness. Internal temperature should be checked with a thermometer in the thickest part of the meat, ideally away from a bone (which retains heat). As noted above, ingredients like fresh vegetables and herbs can harbor bacteria, so be sure to wash all ingredients beforehand, especially those that will not be cooked thoroughly. Finally, preparing meats and other foods in the same area can result in cross-contamination that can lead to foodborne illness, so ensure your workspace is clean before preparing any food.

Stay Out of the Danger Zone

I’m not entirely sure it’s what Kenny Loggins had in mind, but be sure to pay close attention to cooking and storing your food this week and all summer long to prevent your gastrointestinal system from taking the highway straight into the Danger Zone. The Outbreak Observatory team wants to wish everyone celebrating Independence Day this week a fun and safe holiday! And to our international colleagues, we hope this post is a useful reminder of some ways to limit your exposure to foodborne pathogens, particularly during warm weather.


Photo is an F-14 Tomcat onboard the flight deck of a US aircraft carrier; courtesy of Pixabay.

Outbreak Observatory aims to collect information on challenges and solutions associated with outbreak response and share it broadly to allow others to learn from these experiences in order to improve global outbreak response capabilities.