The country’s deposit return machines for recycling cans and plastic bottles do not pose a biological risk to public health, researchers at University College Cork (UCC) have found. The findings came amid public commentary raising concerns that the machines pose hygiene and infection control issues. A team led by Dr John Mac Sharry at UCC’s School of Microbiology analysed samples from the machine and found no threat to public health. “While the call for general cleanliness is valid, it is important to look at the
actual microbial ecology of these machines to avoid unnecessary public alarm,” Dr Mac Sharry said. He added that the research team has been conducting environmental sampling to analyse specific microbes colonising the reverse vending machines. Their data indicated that the organisms present are overwhelmingly “fermenters”, which are primarily common environmental yeasts and non-pathogenic bacteria “that naturally thrive on the trace sugars and alcohol left in unrinsed containers,” Mac Sharry said. “It is absolutely true that these fermenting microbes can produce strong, unpleasant odours, and the
sugary residue can attract pests like flies during the warmer months. “However, our findings show that these microbes act as a nuisance rather than a direct health threat. They are not the harmful pathogens that typically cause human infection; they are the same harmless organisms found ubiquitously in our natural environment and in food fermentation,” he said. Dr Mac Sharry also warned against causing undue alarm surrounding the risk posed by the machines. “Framing the maintenance of these machines as an acute infection-control crisis may
be disproportionate to the actual biological risk. Standard, sensible hygiene practices are more than sufficient,” he said. Retail staff should be provided with basic sanitary guidance, such as wearing gloves when emptying the machines, practising routine handwashing, and regularly wiping down the units with standard cleaning agents. This should effectively manage both the odours and the pest attractants, Dr Mac Sharry said. “The DRS is a highly successful environmental initiative. By understanding that the core issue is basic hygiene and odour management rather than a
hazardous infectious disease risk, we can implement pragmatic, operational guidelines without causing undue anxiety among retail workers and the public,” he said.
deposit return machines, DRS, University College Cork, School of Microbiology, Dr John Mac Sharry, microbial ecology, hygiene, odours, flies, reverse vending machines