Briefs: 72 bacterial species identified in domestic refrigerators
French agency, AFSSA (Agence Française de Sécurité Sanitaire des Aliments) recently conducted a microbiological study on 2 types of refrigeration installations related to domestic food consumption: refrigerated display cabinets and domestic refrigerators. Approximately 50 species were found in display cabinets and 72 were found in domestic refrigerators. Most were brought in by the foodstuffs themselves and constituted Gram+ bacteria were predominant. Staphylococcus xylosus, a bacteria, Debariomyces hansenii, a type of yeast, and Penicillium nalgiovense, a type of mould, all three used as ferments in delicatessen and dairy products, were also common. Two pathogenic species that are potentially harmful to consumers were also found: Staphylococcus aureus, found only in domestic refrigerators and easily eliminated by chlorine and Bacillus cereus which tends to linger in the fruit and vegetable compartment. Most disinfection operations are only useful in getting rid of germs that have not had sufficient time to implant or those that encounter difficulties in growing at low temperatures, but have a very limited effect on established colonies. Another striking finding was that the hygienic conditions of refrigeration equipment was related to their construction materials: for instance bacteria tend to cling to PVC better than to stainless steel.