Temperature and food safety
Much effort goes into making food as safe as possible up to the point of purchase. But how can we keep food safe as consumers? How do we ensure the safety of dishes that we prepare in the home? What practices and precautions can we adopt to prevent food poisoning organisms contaminating and multiplying in our food?
the really important answers are:
• cook food properly, to reach at least 70°C at the centre for 2 minutes
• wash hands and surfaces thoroughly and frequently
• prevent cross-contamination of ready-to-eat foods
• store foods properly; keep hot foods hot (above 63°C) and cold foods cold (below 5°C)
• pay strict attention to storage instructions, and to “use by” dates where these are given on the pack
THE IMPORTANCE OF TEMPERATURE
A crucially important part of food safety in the home is to keep hot food hot and to keep cold food cold. As you will see in the diagram, there is a temperature zone of greatest danger in which pathogens can readily multiply, most rapidly in the middle of that zone. It runs from 5°C to 60°C (41°F to 140°F). For safety it is vitally important to keep food out of that danger zone.
But, is your fridge storing food below 5ºC? If not, you're creating the perfect conditions to grow bacteria and many modern strains can survive cooking. Is your freezer reaching the correct temperature to ensure your frozen food stays safe? A fridge/freezer thermometer will let you see at a glance.
With ovens, even digital thermostats will only tell you what the air temperature is, rather than what the temperature of the food actually is. An oven thermometer is vital if you want to ensure your food is cooked to the correct and safe temperature.
Surveys have shown that up to 60% of raw chickens are contaminated with strains of salmonella bacteria. Bacteria increase in number by dividing in two. Under ideal conditions (within the“danger zone”) they can divide every 20 minutes.
So take 1 bacterium:
in 20 mins. you have 2
in 40 mins 4
in 1 hour 8
in 2 hours 64
in 4 hours 4096
in 8 hours 16,777,216
in 12 hours 68,719,476,736
and remember...this huge number has been produced from just one bacterium!