Objective To investigate the microbial contamination in household air-cooled refrigerators, identify major microbial species, and verify antibacterial effect of copper.
Methods Ten household air-cooled refrigerators were selected randomly by a community health service center to collect samples for determination of five microbes including Staphylococcus aureus, Bacillus cereus, Versinia bacteria, Listeria monocytogenes, and Salmonella. Antibacterial effect of copper was evaluated referring to the national standard Antibacterial and cleaning function for household and similar electrical appliances-Particular requirements of material (GB 21551.2-2010).
Results The disqualified rates for total bacterial count, total fungal count, and Bacillus cereus detected in the household air-cooled refrigerators were 8.7%, 17.5%, and 17.5%, separately. Highest disqualified rates for the above three indicators were found at air ducts (15.0%), places covered by cooled air (35.0%), and back of storage box (45.0%). The antibacterial rates of copper against four common microorganisms (Bacillus cereus, Versinia bacteria, Listeria monocytogenes, and Salmonella) were all above 99% under 37℃ or 4℃ bacterial culturing.
Conclusion The investigated household air-cooled refrigerators present microbial contamination. Opportunistic pathogens are detected in several refrigerators. Copper shows antibacterial effects on four common microorganisms found in refrigerators.
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