Over 100 different bacterial strains were found in swabs taken from microwave ovens in communal areas such as labs and kitchens, according to a recent study that was published in Frontiers in Microbiology.
Scientists from kitchens, labs, and cafeterias, swabbed the interiors of 30 microwave ovens, and the collected samples were then cultured, resulting in significant bacterial growth.
From DNA analysis, it was discovered that these bacteria belonged to common human skin and surface-dwelling groups like Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes.
Among the bacteria identified in kitchen microwave ovens were strains like Klebsiella and Brevundimonas, which can cause foodborne illness. How these bacteria survive and thrive in the harsh environment of a microwave oven remains a mystery and requires further investigation.
According to the researchers, this is the first time that scientists have documented microbial communities living in microwave ovens.
Microbiologist, Manuel Porcar and colleagues who carried out the research, at the University of Valencia in Spain, note that the microorganisms they found in domestic microwave ovens were the same as found on the kitchen surface, some of them pathogenic. However, he stresses that kitchen microwave ovens aren’t a particular cause for concern with nothing to be more worried about than the cleaning of any other part of a kitchen in contact with food.
Because foodborne illnesses are generally underreported and it can be challenging to determine the exact cause of contamination in food and the resultant illness or death, the burden of foodborne diseases on economies and public health has frequently been underestimated.
A 2015 World Health Organisation report on the estimates of the global burden of foodborne diseases presented the first-ever estimates of disease burden caused by 31 foodborne agents (bacteria, viruses, parasites, toxins and chemicals) at global and sub-regional level, highlighting that more than 600 million cases of foodborne illnesses and 420 000 deaths could occur in a year.
The burden of foodborne diseases falls disproportionately on groups in vulnerable situations and especially on children under 5, with the highest burden in low- and middle-income countries.
Similarly, a 2019 World Bank report on the economic burden of the foodborne diseases indicated that the total productivity loss associated with foodborne disease in low- and middle-income countries was estimated at US$ 95.2 billion per year, and the annual cost of treating foodborne illnesses is estimated at US$ 15 billion.
