One of the main concerns when cooking food in a haybox is the growth of bacteria
in food kept warm for a long time. The graph below shows the food safety advice for
the UK. The safety advice in other countries is very similar.
Once food is heated above 70 deg C the micro-organisms are deactivated. As the food
in the haybox cools, then once them temperature drops below 62 deg C, there is a
risk that these will start growing again.
In a well constructed haybox, the time for the temperature to drop to 65 deg C is
more than 3 hours. It will take a further 2 hours for the temperature to drop to
55 deg C. The risk of significant bacterial growth is negligible and the food should
still be safe as long as it is consumed straight away.
The advice from the Apprevecho Research Centre on food safety when cooking in a haybox
“Bacterial poisoning can be avoided by two simple steps. Make sure that the food
is initially boiled for at least 5 minutes. Then keep the lid closed from that point
on and re-heat meat dishes before serving.”
In general, food can be cooked in the haybox for up to 5 hours and then eaten without
having to be re-heated. At above 55 deg C it should still be considered hot. Make
sure to keep the lid on till the food is brought to the table and consume it straight