Bacteria on Can Lids

Beverages in aluminium cans are widely available, and for convenience, drinks are often consumed directly from the can. Cans are exposed to various environments during production, storage and shipping during which the lid may be contaminated with microorganisms. This study on can lid contamination was divided into three experiments to determine (1) the cleanliness of randomly collected cans, (2) the transfer rate from hands to can lids and (3) the survival of bacteria on lids during storage. Over 190 cans were tested for presence of ATP using a standard luciferase enzyme kit. Of the 194 randomly selected cans, 90 (46.39%) were in the dangerous unsanitary category, 60 (30.93%) were considered cautionary as far as sanitation while 44 (22.68%) were categorized as clean. In the second experiment, subjects handled and opened cans with hands inoculated with E. coli and greater than 50% transfer to wet cans lids and greater than 30% transfer to dry can lids was found. In the third experiment, inoculated can lids were found to harbor E. coli for up to 14 days.