Microbiological quality of packaged ice from various sources in Southern California

Microbial contaminations in food and water may post a threat to public health. Ice is defined as a food by the U.S. Food and Drug Administration (FDA). According to the International Packaged Ice Association (IPIA), approximately 2 billion bags of ice are sold from retail, wholesale, and vending producers each year in the U.S. Out of 700 commercial ice-making companies, 200 of the aforementioned are not represented by the IPIA and do not comply to specific packaged ice processing standards. Potential sources of microbial contamination in ice may come from water, equipment, and handlers. Non-IPIA complied samples were collected from gas stations, liquor stores, or convenient stores in Los Angeles and Orange counties. The microbiological quality of non-IPIA complied ice samples were compared the results with the IPIA-complied packaged ice samples using microbiological, molecular, and sequencing analyses. Among the 132 non-IPIA complied packaged ice samples analyzed, 15 samples contained unsatisfactory level of heterotrophs (≥ 500 Most Probable Number [MPN]/100 ml), 12 samples contained unsatisfactory level of coliforms (≥ 1 MPN/100 ml), 19 samples had Staphylococci, and 70 samples had yeast/molds. None of the 24 IPIA-complied samples had unacceptable microbial levels. None of the samples analyzed showed the presence of the pathogen, Salmonella. Our results revealed the microbiological quality of non-IPIA and IPIA complied ice samples in Southern California. These findings may lead to a better enforcement of processing standards on packaged ice.