The Water activity (aw) is a critical factor in the field of food science and plays an important role in determining food safety, stability and quality. It is a measure of the amount of water available for microbial and chemical reactions in a food system. The water activity scale ranges from 0 to 1, where pure water has an aw value of 1,0 and values ​​below 0,6 are generally considered inhibitory to the growth of most microorganisms.

There are several reasons why water activity is important for food:

1. Controlling Microbial Growth: Water is essential for the growth of microorganisms, including bacteria, yeast and mold. By controlling water activity, food manufacturers can limit or inhibit the growth of these microorganisms, thereby reducing the risk of spoilage and foodborne diseases. Most bacteria require an aw value of at least 0,91 to grow, while molds and yeasts can grow at lower aw values.

2. Extension of shelf life: Controlling water activity can help extend food shelf life. By reducing the available water, manufacturers can create an environment where microorganisms cannot thrive, slowing the spoilage process. This is particularly important for products that have a longer shelf life or need to be stored for a long time.

3. Food safety: Water activity affects food safety by inhibiting or promoting the growth of pathogenic bacteria such as Salmonella, Escherichia coli and Listeria monocytogenes. Low water activity can prevent the growth of these harmful bacteria, making the food safer to eat.

4. Preservation Techniques: Water activity is considered when choosing the appropriate food preservation methods. Processes such as dehydration, freeze-drying and salting aim to reduce water activity to inhibit microbial growth and preserve the food. By reducing water activity, food becomes less prone to spoilage and retains its quality for longer.

5. Texture and sensory properties: Water activity affects the texture, crispness and sensory properties of foods. Many products, such as snack foods, cookies and baked goods, require a specific water activity to achieve the desired texture and crispiness. High water activity can cause softening or soaking, while low water activity can cause brittleness and undesirable texture changes.

6. Chemical reaction: Water activity influences various chemical reactions in food, including enzymatic and non-enzymatic reactions. Some reactions, such as B. the lipid oxidation and enzymatic browning are accelerated at higher water activities, which leads to a deterioration in quality. Controlling water activity can help mitigate these reactions and preserve food quality and appearance.

7. Packaging Considerations: Water activity is an important parameter to consider when choosing suitable packaging materials. When a food's water activity is too high, moisture migration can occur, leading to undesirable texture changes, microbial growth and possible packaging defects. Understanding water activity helps design appropriate packaging systems to maintain product quality and safety.

In summary, water activity plays a crucial role in food safety, preservation, shelf life extension, texture and overall quality of food products. By controlling water activity, food manufacturers can ensure product stability, reduce spoilage and increase food safety for consumers.

With the humimeter RH2 Water activity measuring device you can easily and quickly determine the water activity of your food. Two different sensors guarantee the optimal type of measurement, depending on the nature of the material.

We would be happy to advise you personally on our user-friendly, highly professional laboratory device. More information can be found here: humimeter RH2 aw value tester