Defocused blur of supermarket shelves with cheese.

Contributed By Kaivac.

Most forms of bacteria prefer moderate to warm conditions. Not so with psychrotrophic microorganisms — they like colder temperatures, around 40 degrees (F), if not chillier. It's because of this, they are often found developing in, of all places, cooler display cases in supermarkets.

“Sometimes these organisms, which are different forms of bacteria and fungi, are brought into the display case when food is shipped,” says Mike Perazzo with Kaivac. "Other times they develop as food deteriorates in the [refrigerated] display case.”

According to the Valencian Institute of Microbiology, a private reference laboratory, “psychrotrophic microorganisms are the main microorganisms involved in the deterioration of refrigerated foods.”

If food containing psychrotrophic bacteria is purchased and later consumed, it can be a health risk. For supermarket professionals, these microorganisms can develop on display cases and shelves, destroying hundreds of thousands of dollars' worth of food products each year, seriously cutting into profit margins.

The food products most likely to become contaminated with psychrotrophic microorganisms are the following:
·      Products of animal origin, primarily raw or cooked meats
·      Fresh or cooked seafood
·      Fruits and raw vegetables
·      Dairy products, especially milk, as well as cheese and butter
·      Ready-to-eat and grab-and-go foods

Making matters worse, as these microorganisms grow, biofilms can develop on shelving. Biofilms are sheltered bacterial communities that are exceedingly difficult to remove.

To detect psychrotrophic microorganisms, display cases must be swabbed. Those swabs must then be sent to a laboratory for testing. Results can take hours or a few days.

“Testing is usually not practical or possible in most grocery or convenience store settings,” says Perazzo. “The best option is effective cleaning of cooler displays. This helps remove [psychrotrophic] microorganisms from display cases and prevents the growth of future microorganisms."

To clean display cases, Perazzo recommends cooler display case cleaning systems that can be used by in-house staff. These system apply cleaning solution to shelves, fans, condenser coils, and refrigeration components. Areas are then pressure rinsed, removing psychrotrophic microorganisms and other pathogens, which are then vacuumed up by the machine.