Listeria warning over caramel apples

http://www.bbc.co.uk/news/health-34514349

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Caramel-coated apples can be riddled with listeria - a type of bacterium that causes diarrhoea and vomiting and, rarely, meningitis - warn scientists.

Inserting the stick into the apple causes a little bit of juice to leak and that moisture, trapped under the candy layer, becomes a breeding ground, a study shows.

To be safe, consumers should eat them fresh or store them in the fridge.

The study in mBio was prompted by an outbreak in the United States.

In January 2015, a few US companies voluntarily recalled their caramel 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 the autumn and winter of 2014.

Thirty-four were admitted to hospital and seven died. Listeria contributed to at least three of these deaths.

Researcher Dr Kathleen Glass at the University of Wisconsin-Madison's Food Research Institute said: "It just didn't make sense to us that people would get sick from the apples. So we wanted to investigate."

Her team tested a batch of apples to see what factors might allow the bacteria to grow and thrive.

They swabbed the skin, stem and base of some Granny Smith apples with the same strains of listeria that had been linked to the US outbreak.

Next, they pushed wooden sticks through the stems of half of the apples. Then they dipped all the apples into hot caramel using either the sticks or tongs.

The apples were allowed to cool and were then stored at either room temperature or in a fridge.

Compared with the other apples, the ones on sticks that had been stored at room temperature grew lots of the bacteria.

Listeria

Neither caramel, because of its low amount of water, nor apples, because of their acidity, are normal breeding grounds for listeria.

But together they can create a perfect growing environment for any bugs trapped in between, say the researchers.

Dr Glass said: "It's low risk but it's not no risk. I don't want people to be worried, but it can happen, depending on how they are stored."

It's not clear if the same is true for toffee apples. "That hasn't been studied," she said.

A Food Standards Agency spokesman said: "Refrigerated storage and shelf life are key food safety controls to prevent listeria growth."