Microbiology Food Safety

Microbiology Food Safety

Microbes in Food

Microbiology is the branch of science that deals with microorganisms. Microbes are single-cell organisms and so tiny that millions can fit into the eye of a needle. they live in us, on us and around us. Micro-organisms matter to us because they affect every aspect of our lives and in the food and drink industry we have challenges placed upon us every minute of every day to ensure we maintain our water and food security for a healthy population.

Lets take a look at 4 types of microbe:


A bacteria are a single cell microbes. Microbes that cause disease are called pathogens. Below is an image of E.coli 0157.

Image of e Coli - Microbiology Food Safety

Bacteria come in three main shapes:

  • Spherical (like a ball).  These are usually the simplest ones. Bacteria shaped like this are called cocci (singular coccus).
  • Rod shaped. These are known as bacilli (singular bacillus). Some of the rod-shaped bacteria are curved; these are known as vibrio.
  • Spiral. These are known as spirilla. If their coil is very tight they are known as spirochetes.


Viruses stand out as being different from all the organisms that are dealt with in Microbiology. Viruses need another living cell to multiply (parasite) and are categorised as a particle and being acellular (not composed of cells) and non-living, therefore, what is non-living is difficult to destroy. Current food hygiene guidelines, which are optimised for the prevention of bacterial growth, may not be effective against viruses.

Below is an image of Hepatitis A, one of the the viruses associated with food poisoning.

Image of a Virus - Microbiology Food Safety


Yeast are single-celled microorganisms that are classified, along with moulds and mushrooms, as members of the Kingdom Fungi.

Image of Yeast - Microbiology Food Safety


Mould is a term used to refer to fungi that grow in the form of multi-cellular thread-like structures called hyphae.

Mould growing in a dish - Microbiology Food Safety

Mould growing in a dish

Microbe magic or not?

95% of all microbes are good, so we don’t have to worry about them all. There are more than 400 different species of bacteria living in your gut! Trillions of cells that together weigh about 2 kg. They are essential for your intestine to function efficiently and fight disease and infections, keeping you healthy. For example, you have good bacteria and yeast in your gut which aid your digestion.  The ‘bad’ have the ability to make us ill, these are called pathogens, also known as pathogenic.  A large number of pathogens can cause intestinal disease. These include bacteria, viruses, protozoans and fungi.

There are microbes that do not cause illness and are referred to as spoilage. These are the microbes that are not pathogenic, and therefore, don’t generally make you ill, however, the food, usually highly perishable, is unfit for consumption.  The signs of food spoilage may include an appearance different from the food in its fresh form, such as a change in colour, a change in texture, an unpleasant odour, or an undesirable flavour, if this is evident then the food should be discarded.

So, to summarise, bring on the good guys as we don’t need to worry about them.

Pathogenic microbes we need to eliminate, as these will make our customers sick. Absolutely essential to ensure we are providing legal, safe, quality, wholesome and nutritious food

And spoilage microbes which we need to reduce wherever possible, as they will cause us complaints. It’s all about quality!

Short but hopefully helpful. I will publish more over the next few weeks and thanks for reading.

Bob Elsey

Learn more about food safety.


Leave a comment

Your email address will not be published.