BBC Radio 4 The Food Programme, What Makes Food Safe ...

The World Health Organisation suggested there was a link between rise in E. coli cases and the overuse of antibiotics to treat humans or to prevent disease in intensively reared animals, both leading to a dangerous spread of antibiotic resistance. Sheila notes: “That was the theory put to the test when the EU banned antibiotics in animal feed in 2006, and the cases of 0157 E. coli generally began to fall in the UK.”

The environment is among other factors in the spread of E. coli

Other explainers for the rise in harmful E. coli strains include feed – “animals fed on grains seem to have more toxic aspects in their guts than animals reared on pastures,” says Sheila.

Meanwhile, microbiologist Professor Catherine Donnelly points to some big picture factors – for example, medical interventions such as chemotherapy impact the immune system, something, she argues, we should be more aware of. Professor Donnelly also cites the environment. “Look what's happening to our climate across the globe, the flooding events that are moving pathogens from places where they wouldn't normally move if that wasn’t happening.”

Raw milk chesses have come under scrutiny

Despite the evidence about the foods that cause most E. coli illness, some unpasteurised diary products like raw milk cheeses have come under scrutiny. Sometimes this can be for protectionist reasons such as in the US where legislation against unpasteurised products has been particularly – and deliberately – harsh.

The effect is that some raw cheese makers are moving to pasteurisation through the fear and stress of being linked to an outbreak. In fact, softer cheeses do carry a higher risk from microbes such as E. coli, and even pasteurisation isn’t foolproof. However, food safety issues like STEC are, according to Bronwen Percival, technical director of Neal’s Yard Dairy cheesemongers, “not even primarily a cheese issue: this is a fresh vegetable issues salad issue; this is a rare burger issue – this is an issue that's been associated with things like nut butters and dried fruit and things that we would consider entirely 'normative’ and part of a normal diet.”