JAPAN – An E. coli outbreak which unfolded in June 2021 in Toyama City, Japan, has been linked to milk served in local schools.
The incident involved 1,800 cases across 25 schools, although mercifully, no fatalities were recorded.
The enigma began when scientists identified an elusive E. coli strain, serotype OUT (OgGp9): H18, in both milk samples from the implicated batches and the afflicted patients.
Astonishingly, these strains were an exact match, indicating a direct link between the contaminated milk and the outbreak.
The affected individuals exhibited symptoms consistent with diarrheagenic E. coli infection, including abdominal pain, diarrhea, vomiting, and fever, mirroring the sinister nature of this mysterious contamination.
However, the E. coli strain, OUT (OgGp9): H18, was not a typical enteroaggregative E. coli (EAEC) as it lacked the typical EAEC virulence factors.
The milk, supplied by the T milk factory and an integral part of school lunches, was pinpointed as the source of the crisis.
Pasteurized at 128 degrees Celsius (262 degrees Fahrenheit) for two seconds, the milk should have been safe for consumption. However, the investigation unearthed startling lapses in hygiene and quality control within the factory.
An inspection revealed a series of potential risk factors, including unsanitary handling leading to cross-contamination between pasteurized and raw milk, insufficient cleaning of raw milk tanks and carton packing equipment, failures in temperature control, and structural defects in surge tanks for pasteurized milk.
These findings suggested that the contamination might have occurred after the pasteurization process.
The outbreak, spanning just two days in June, continued for several days, indicating a persistent flaw in the production and packaging process.
The lack of cleaning on manufacturing lines and potential sanitary oversights emerged as significant concerns, further deepening the mystery surrounding the origin of the outbreak strain.
Despite these findings, the exact origin of the outbreak strain and the specific factors leading to the contamination of milk cartons remained unclear.
As Toyama City grapples with this confounding incident, public health officials, scientists, and the community at large are left searching for answers.
The inexplicable nature of the contamination, coupled with the potential risks lurking in the very food meant to nourish young minds, underscores the urgent need for stringent quality control measures and heightened vigilance within the food industry