As the heat wave continues, there have been repeated cases of indoor temperatures at home far exceeding 40 degrees. Measurements are frequently posted showing that in sun-drenched balconies or homes with the air conditioner off, indoor temperatures have surged to 45~49 degrees.

At times like this, a question comes to mind for everyone. The label says to ‘store at room temperature’; does 49 degrees count as room temperature? The short answer is no.

‘Store at room temperature’ means to keep it indoors; it does not mean it can be stored at any temperature. The problem is that although food packages say ‘store at room temperature’, there is no uniform legal standard, domestically or internationally, that defines how many degrees this means.

In South Korea, the Ministry of Food and Drug Safety likewise has manufacturers set storage methods in consideration of product characteristics and manufacturing processes, and requires separate labeling for foods that need refrigeration or freezing, such as ‘0~10℃’ or ‘Keep refrigerated’.

Overseas, the situation is similar. In the United States, there is no legal definition of ‘room temperature’ that applies to foods, and manufacturers set appropriate storage conditions according to product characteristics. The European Union (EU) also has safety standards by food type, but does not define ‘room temperature’ as a specific temperature. Japan’s Ministry of Health, Labour and Welfare merely describes ambient temperature as a temperature that does not exceed the outside air temperature, without uniformly stating how many degrees it means.

Ultimately, most countries follow product-specific storage labeling and food safety standards rather than the term ‘room temperature’ itself. In the food industry and the pharmaceutical field, however, 15~25℃ or 15~30℃ is often used as a reference range for ambient conditions. This is not a public standard that applies to all foods.

Experts say the ‘environment’ matters more than the number itself. The premise of ‘store at room temperature’ is a place without direct sunlight, with low humidity, and with little temperature fluctuation over the day.

Therefore, spots where heat builds up in summer, such as a sunny windowsill, next to a gas range, or around a microwave or rice cooker, are hard to regard as ‘room temperature’. Especially during a prolonged heat wave like now, some indoor zones exceed 40 degrees, so room-temperature storage may not be appropriate.

The U.S. Department of Agriculture (USDA) explains that leaving foods for a long time in the 4~60℃ ‘danger zone (Danger Zone)’ can allow bacteria to multiply rapidly. However, this guideline mainly concerns cooked foods or items that require refrigeration, and it does not mean that all products that can be stored at room temperature, such as sterilized canned goods or retort foods, are dangerous.

Quality deterioration is another problem. In ultra-high temperatures, not only can microorganisms grow, but fat rancidity accelerates, vitamins break down, and color and aroma change, leading to declines in taste and quality. Chocolate melting or cooking oil turning rancid quickly happens for the same reason.

Another point to keep in mind is that ‘store at room temperature’ usually assumes an unopened state. Many products switch to refrigeration after opening, so be sure to check the package for ‘storage instructions after opening’.

If a heat wave pushes indoor temperatures to 40~50 degrees, that space is already difficult to consider a typical ‘room temperature’ environment. Even within the same home, a cool pantry or cupboard that is shaded and well ventilated is much more suitable, and if temperatures are high enough to exceed the range allowed by the manufacturer, the safest course is to check whether the product can be refrigerated or to follow the manufacturer instructions.