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22.10.2019 - Microbiology
What is the significance of molds in food?
Profile on "Mold"
General Information and Origin
Molds are widespread in our environment (soil, plants, air, water, humans...) and are therefore found in many foods.
In plant-based foods such as cereal products, nuts, herbs, spices, vegetables, and fruits, molds regularly appear in excessive numbers. Dried foods of animal origin, such as cured raw products, can also be affected by spoilage due to molds.
Significance
Depending on the food group, a certain number of molds is tolerated in most foods. However, if these levels are exceeded, it indicates possible spoilage of the food. Unlike most bacteria, many molds have the special ability to grow even at low water contents and/or low pH values.
Some molds can also pose a health risk to consumers as they can produce highly toxic mycotoxins (e.g., aflatoxins, ochratoxins, fusarium toxins, patulin, ...). Moldy raw and intermediate products should no longer be processed, as the toxins are partially very resistant (e.g., heat-resistant) and can survive processing.
Important Causes for Excessive Numbers
- Processing contaminated raw materials
- Improper storage (excessive humidity or temperatures, prolonged storage duration…)
- High number of molds in the ambient air (storage, production site)
- Poor production hygiene
Growth Conditions
- Temperature: Growth at 0 – 60 °C
- pH Value: Growth at 3.0 – 7.0
- aw Value: Growth down to min. 0.62 – 0.85
- Oxygen Requirement: Aerobic; under anaerobic conditions, some molds can ferment – however, growth is usually inhibited after a short time
At What Temperatures Do These Microorganisms Die?
Generally, it can be assumed that most molds are killed when heated to +72 °C for at least two minutes or by an equally effective process. In foods, it should be noted that this temperature-time combination must be reached at the core of the product to safely kill the molds.
However, it should be noted that there are also very heat-resistant types of molds that can survive the aforementioned temperature-time combination.
Additional Information and Literature
- www.lgl.bayern.de: under "Food" and then "Hygiene"
- Food Microbiology, J. Krämer and A. Prange, 7th edition 2017
- Leaflet "Safely fed - Especially vulnerable groups in community facilities", Federal Institute for Risk Assessment, Berlin 2017
- Microorganisms in Food, H. Keweloh, 2nd edition 2008
In our laboratory, we regularly conduct mold testing. We provide you with fast and reliable results.
For any questions, our customer advisors are very happy to assist you.