1. What is Listeria?

Hello, I'm Jennifer Ziegler, Jenny for short


I am your trainer for this e-learning. Perhaps we already know each other from other training courses that I conduct. 

What is Listeria?

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 Click the play button to start the video and learn more about the Listeria bacteria group. And why Listeria in food is so dangerous.


By the way: There are several types of Listeria. The germ Listeria monocytogenes is dangerous for humans.


Tree, flowers, meadow

Listeria are among the germs that are found almost everywhere in the environment. It's natural.

It is important that we control them in our food.

living conditions

Listeria are real survivors compared to other germs. 

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Click on the blue dots for more details:

Refrigerated display case, refrigerated shelf


Listeria can grow with AND without oxygen.

So also in packaged food.

Even when shielding gas is used.


Listeria grow in food,

too dry for other germs,

are too salty or too acidic.

Examples are raw ham, parmesan, soft cheese.


Listeria grow at -1.5 to 45 °C.

So also in the fridge!

The warmer it is, the faster Listeria grows.


Listeria need only a few nutrients. 


Listeria can become resistant to certain disinfectants.

This is when the disinfectants are not used correctly.

deep freezing

Listeria cannot grow when frozen. 

However, the low temperatures do not harm the germs. 

If the food is thawed, the germs grow again.

Did you understand everything?


Join us in the next chapter to learn more about why Listeria is a problem in food.
Let's test your new knowledge first. press for it Knowledge test chapter 1