Bacterial growth requirements for food security

As food safety bacteria are very similar to us, they need similar conditions to grow. The main requirements are food, humidity, heat and time.

Food and humidity.

There are four main types of food:

· High-risk foods

· Raw food

· Low-risk foods

· Ready for consumption of raw food.

High-risk foods are common in outbreaks of food poisoning. They are usually composed of proteins, ready to eat, stored under refrigeration and without further processing, as required for baking. Examples include potatoes, sandwiches, stuffed rolls, fresh cream and artificial cream, pastries and freshly cooked meats.

Raw foods are an important source of poisonous organisms. High-risk foods should be kept separate from raw foods at any time or cross-contamination will reduce food safety and food poisoning.

Low-risk foods do not pose a risk to food safety, especially as they do not have one or more of the requirements for bacterial growth. They could be acidic foods with a pH below 4.5, can have high levels of sugar, salt or fat, good natural preservatives. They can be dry or canned food that does not require refrigeration. They may be foods that require storage at room temperature.

The last category of food is ready to eat raw food. These include vegetables, fruits and salad and should be thoroughly washed prior to consumption to minimize the risk of low dose pathogens.

High-risk foods contain enough moisture for bacterial growth.


The next aspect to consider is heat. If we control the heat, bacterial growth will not occur.

The maximum recommended temperature for the freezer is -18 ° C. At this temperature, there is no growth of bacteria, the bacteria remain dormant. Although some bacteria are eliminated during the freezing process, many remain alive.

The temperature of the refrigerator should be between 1 and 4 ° C. Although the legal maximum temperature cooling in the UK is 8 ° C at cooling temperatures, some bacteria grow very slowly, including Listeria and C. botulinum.