Factors Affecting Microbial Growth that Food Safety Workers Should Know

food safety program

In foods where there are sufficient nutrients and favourable conditions for growth, microorganisms can thrive. The most important of these microorganisms to consider is bacteria, since while they are often harmless or beneficial, they can be very dangerous. Yeasts, molds, and viruses are other microorganisms that can exist in food and cause safety threats.

In your career, you will need to be aware of factors creating the ideal environment for these tiny life forms to grow, so that you can mitigate risks. Read on to learn more about which factors affect this, how you can keep food safer by monitoring it, and why the combined factors of temperature, moisture, and pH matter in keeping the public safe.

Temperature Plays a Key Role in Food Safety Worker Careers

One of the most important factors to consider with microbial growth is temperature.

  • In most cases, rising temperatures have a positive correlation with enzyme activity in food.
  • Bacteria are the microorganisms that create enzymes.
  • Enzymes can cause spoilage.

However, not all bacteria grow at the same temperature. There are various categories of these microorganisms, organized by optimum growth temperature.

Psychrophiles grow optimally in cooler temperatures.

Mesophiles are more suited to moderate temperatures.

Thermophiles prefer to grow at hotter, higher temperatures.

Knowing what temperature various foods need to be kept at will help you to control microbial growth. Most bacteria grow within the range of 5 to 60 degrees Celsius, so the majority of foods are kept out of this zone as much as possible. This range is often referred to as the danger zone.

  • In general, hot foods should be kept hot and cold foods should be kept cold to avoid excess microbial growth.
Temperature must be monitored in industrial freezers to ensure food is being kept in a safe range

Temperature must be monitored in industrial freezers to ensure food is being kept in a safe range

How Will You Monitor Moisture After a Certificate in Food Safety?

Your food safety program will help you understand how to keep conditions ideal for food to be safe for consumption. Moisture content in food plays a large role in the number of microorganisms it contains. The amount of water available in the food can encourage or discourage growth. This moisture can be measured using water activity (aw).

Water Activity (aw) is expressed as a ratio, between vapor pressure of a food and vapor pressure of distilled water in the same, undisturbed environmental conditions.

Moisture content is an interesting factor, as safe levels differ between foods. This is because of the difference between free water and bound water:

  • Bound Water: This water is physically bound to and trapped inside of crystals like starch or other components. The liquid can’t be squeezed out of or separated from the food.
  • Free Water: This water can separate from food and is not trapped within it. This includes water that will sit on top of yoghurt or juices in citrus fruits.

Only free water can encourage and promote microbial growth. Bound water cannot. So, if a food has high moisture content but most of the content is bound water, this will affect its ability to spoil quickly.

Watermelons and cucumbers are foods with high moisture content

Watermelons and cucumbers are foods with high moisture content

pH in Food and why Food Safety Workers Should Understand it

As a future food safety worker, you are likely familiar with botulism. The botulinum toxin, clostridium botulinum, that can appear in canned food products causes this dangerous illness. Clostridium botulinum is a bacteria that multiplies in environments with no oxygen.

When foods are in a can or void of oxygen, pH levels are important to prevent growth of these dangerous bacteria. Acidic foods, with a pH under 4.6, prevent growth of clostridium botulinum.

  • pH is expressed as a number on a scale to show the alkalinity or acidity of a food. A number 7 on the scale is neutral, with lower values indicating higher acidity and higher numbers indicating lower acidity.
A low pH is important when canning foods like pickles, since they will be in an oxygen-free environment

A low pH is important when canning foods like pickles, since they will be in an oxygen-free environment

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