When health authorities in the US grappled with the source of an outbreak of listeriosis in 2015, they were shocked to discover that commercially produced toffee apples turned out to be the cause.
“Who would have thought that you would have found listeriosis in toffee apples! You wouldn’t normally ask people ‘have you eaten toffee apples’?” said Professor Lucille Blumberg, deputy director of the National Institute for Communicable Diseases..
In January 2015, a few US companies voluntarily recalled their toffee apples after routine testing at an apple-packing facility revealed contamination with listeria.
A total of 35 people had become infected across 12 states in 2014.
Thirty-four were admitted to hospital and seven died. Listeria contributed to at least three of these deaths.
In South Africa, health authorities believe they are “moving in the right direction” and could soon find the source of the outbreak that has claimed the lives of 172 people.
So far, Gauteng has accounted for 59% of reported cases, the Western Cape 12% and KwaZulu-Natal 7%. There have been 915 laboratory-confirmed cases.
“We still have a number of tests to do but we are moving in the right direction,” Blumberg said
She stressed that tracking down the source of a listeriosis outbreak could be difficult. One of the challenges is that listeriosis has an incubation period that can range from six hours to 70 days.
The bacterium usually occurs in soil, water, vegetation and in the faeces of some animals. It also contaminates a wide variety of food types, including meat and dairy products.
Blumberg warned that members of the public who were at risk of developing listeriosis, including pregnant women, the elderly, and people with weakened immune systems, should avoid foods linked to the outbreak.
These include processed, ready-to-eat meat products, soft cheeses and unpasteurised milk and dairy products.
They suggested that processed meats should either be avoided, or cooked in boiling water or heated to 70Cº or higher before eating.