99 per cent of kids' lunchboxes kept at unsafe temperatures, Bournemouth University (BU) study finds
29 November 2012
Around 99 per cent of children's lunchboxes tested as part of a Bournemouth University (BU) study reached potentially unsafe temperatures.
The research - conducted by senior lecturer in Food Safety Philippa Hudson and dissertation student Hannah Walley - took place at a junior school in Dorset where more than half of pupils took in a packed lunch.
Lunchboxes at the school were kept in trays in corridors, and temperatures were measured throughout the day over a school term.
The results showed that all but one of the lunchboxes - which had a large ice pack inside - reached potentially unsafe temperatures.
"There has been a lot of concern about healthy eating and what children are putting in their lunchbox, but nothing about how safe the food is in their lunchbox," said Philippa.
"The lunchboxes started off refrigerated, but by about 10am they were at ambient temperature.
"After being in the sun, they went up to 20-24 degrees, which is the temperature at which bacteria grows very rapidly so the risk factors are there."
Only 20 per cent of parents questioned put ice packs inside their children's lunchboxes, but Philippa said that the small packs did not make much of a difference.
"The small ones are a waste of space," she said.
"The big ones are much better and maintain the temperature better, but they are not particularly practical as they are so much bigger and take up half of the lunchbox."
The insides of the lunchboxes were also tested for micro-organisms, and Philippa said that children bringing food leftovers home could lead to cross-contamination.
She said: "The practice of sending uneaten food and other waste home means that food debris frequently comes into contact with the surfaces of children's lunchboxes.
"High-risk food leftovers could potentially become unsafe if kept at ambient temperatures and food debris could accumulate in inadequately cleaned boxes, contaminating food items subsequently placed into the boxes."
She said that the microbiology results were "far higher than expected."
"We got huge counts, but all we could say is that it is very large," she said, adding that it was something they hoped to do further research around.
"In terms of analysing risk factors, there was an awful lot present and the conditions exist for them to grow and to persist and even contaminate other high-risk ready to eat foods."
The majority of children took fabric lunchboxes to school, which Philippa said are much more difficult to clean.
"Washing up liquid is good but every now and then, they could probably do with going through the washing machine if they are the fabric ones."
She added: "It is better to buy plastic lunchboxes that you can put in the dishwasher. It means that it is being washed and dried properly.
"Don't just wipe them out with a dishcloth - we all know how contaminated they are. You are literally spreading the problem rather than removing it."
Since publishing the research, Philippa has been contacted by pupils from the sixth grade class of Rollings Middle School of the Arts in South Carolina, USA.
They developed the idea of a lunchbox that is placed in the freezer before use to keep it at a lower temperature throughout the day.
Philippa has offered advice and feedback on the construction, materials and prototype concept, which the children designed for a competition.
"They did really well with the project and got through to the regional finals," she said.
Philippa's Top Tips for a safe lunchbox:
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