Refrigerator Temperature Needs to Be Better Managed
-Many Chilled Food Showed Higher than 10℃ Surface Temperature-

Many mega-scale discount stores do not seem to manage the food refrigeration temperature properly, which increases the possibility of bacteria multiplication. Also, food products placed on the same display shelf showed different surface temperatures depending on where they were placed, according to the Korea Consumer Agency (KCA)’s study result on surface temperatures of chilled foods displayed on the shelves at 11 mega stores, 5 department stores, and 5 convenience stores.

□ Poor Temperature Management for Chilled Foods

When the KCA measured the surface temperatures of 582 packed milks and “convenience salads,” 453 of them (77.8%) showed over 10℃, while the temperatures, even on the same display shelf, showed wide disparities up to 10.7℃, depending on their location.

More specifically, out of total 336 surface temperature measurements of packed milks, 244 (72.6%) times exceeded 10℃ with temperature gaps on the same shelves from 0.1℃ to 10.3℃. The surface temperatures of salads were measured 246 times, and 209 times (85.0%) showed temperatures exceeding 10℃.

It can be more difficult to manage the temperature of open-style refrigerators (display shelves) than that of closed-style ones. Therefore, it is important to develop a more advanced refrigerating system through which the refrigerator temperatures are less influenced by outside conditions, defrosting times can be shortened, and the amount of cold air from the jet holes can be more easily controlled. It is also necessary to clearly divide the spaces for general food products and for chilled products only. Equally important is to avoid overloading, since the excessive amount of foods displayed on the limited space of a shelf can cause a temperature rise. Therefore, proper education on how to display the products, and monitoring on load conditions should be regularly carried out.

□ Differences in Bacteria Multiplication in Foods Depending on Storing Temperature   

According to the KCA’s simulation tests to find out the correlation between temperature and bacterial growth, those foods stored at 5℃ and 10℃ showed constrained or slowed bacterial multiplication, while the growth of bacteria was accelerated in the foods preserved at 15℃ and 20℃, which indicates the importance of proper management of refrigeration temperature.

When the Agency conducted the simulation tests with bean curds, no germs were detected in any bean curds on the 1st day. However, on the 2nd day, some germs were found in the bean curds preserved at 20℃, and on the 3rd day, even those kept at 15℃ showed speedy bacterial growth. Meanwhile, no bacteria was found in the bean curds preserved at 5℃ and 10℃ until the 5th day. 

                                       Bacterial Growth Detected in the Simulation Test for Bean Curds                       (Unit:CFU*/g)

* CFU refers to colony forming units or the number of viable bacteria recovered as based on colony

In the same tests with convenience salads (packed salads sold at convenience stores or discount stores), germs were found from the 1st day in all tested salads although there were some differences in the speed of multiplication.

                                   Bacterial Growth Detected in the Simulation Test for Salads                        (Unit:CFU*/g)

□ Some Refrigerated Display Units with No Thermometers

The KCA also checked whether refrigerated display decks at convenience stores and discount stores were equipped with thermometers so that consumers can see the refrigeration temperature. The result shows that out of 99 refrigerated display shelves, 95 (96%) had thermometers while the rest 4 didn’t have any temperature indicators.

Based on its research result, the KCA is planning to ask the relevant authorities to strengthen the management of food storing temperatures, to obligate the indication of refrigeration temperatures, and to improve the refrigeration system of display shelves. Also, the Agency advised consumers to be careful when they buy chilled food and keep it in the refrigerator as soon as they get home.

Aug 3, 2007 [Food & Microbiology Team, Testing & Research Center]