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Agenda: We can be certain a major outbreak of food poisoning will strike again

On May 7, 1964, a catering-size can of corned beef from Rosario, Argentina, was opened in a supermarket in central Aberdeen.

Half the contents were put on a shelf behind the cold meat counter and the other half went into the window.

The sun shone on the meat, which wasn't sterile. It had been contaminated after cooking when the can was cooled with untreated water from the River Parana, into which human waste was discharged daily from Rosario, where typhoid was common. The bacteria in the corned beef in the window grew vigorously.

The first person to fall ill developed symptoms on May 12 and the first definitive diagnoses were made on May 20. By the outbreak's end, 503 people had been admitted to hospital with typhoid, 403 with bacteriological confirmation. Nobody died from typhoid in the outbreak, thanks to antibiotics, so in that regard it was modern. But aspects of its management were conducted as though the Second World War was still in progress. The names and addresses of those admitted to hospital were published in the local paper and the end of the outbreak was announced as the "all clear".

Dr Ian MacQueen, then Aberdeen medical officer of health, took control of the outbreak. I believe his handling of it verged on the ridiculous. He believed dramatic statements of risk were necessary to prevent the spread of infection. Aberdeen became in his description the "beleaguered city", and beef cattle raisers in Paraguay, Kenya and Tanzania suffered economically as importing meat came to be seen as high risk in the initial panic.

Dr MacQueen recommended that nobody should paddle in the sea and Union Street was sprayed with disinfectant. There was an obsession with "wave after wave of infections" from poor personal hygiene.

This was always very improbable. All the infections were caused by eating contaminated corned beef or cold meats cut with the same slicer. New cases continued to appear not because the source of infection was still active but because the incubation period was often long.

Could the events that happened in Aberdeen 50 years ago be repeated? Cans of food are unlikely to be the source nowadays because canning practices are almost certainly better (leaving aside labelling in the horse meat scandal). Typhoid is still common in countries whose drinking water is regularly contaminated with human faeces.

But an even nastier organism caused the most recent big food-borne outbreak in Europe. It happened in 2011 in Germany. The organism was E.coli O104:H4, a brand-new bacterium that had evolved as a hybrid of two other disease-causing E.coli strains. More than 3500 fell ill, 855 developed serious complications and 53 died.

As in Aberdeen, the organism was imported. It came on the surface of fenugreek seeds which had left Egypt by boat on November 24 2009, arriving at an organic sprout producer near Hamburg on February 10 2011.

Seed sprouting is ideal for bacterial growth. But identifying the seed sprouts as the cause of the outbreak was difficult and slow, because they were used as a salad garnish and many victims were not aware they had eaten them.

An important step forward in tackling such outbreaks has been global food safety standards. The worldwide adoption of the hazard analysis critical control points system (HACCP, developed by NASA to protect astronauts from food poisoning) makes it less likely that the world food supply could lead to a major epidemic.

But food poisoning is more common than a century ago. The number of sufferers from the UK's number one cause, campylobacter, has been estimated at 500,000 people each year. To some extent this is down to better diagnosis, but probably not entirely. The realities of 21st century mass production of cheap meat are likely to have driven up infection.

Above all else, the big lesson from Germany was that a major outbreak could still take us completely by surprise. With microbes evolving as they do, we can be certain it will happen again.

Contextual targeting label: 
Food and drink

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