What effect does food with an Aw of .85 or greater have on bacteria?

Food with a water activity (Aw) of 0.85 or greater provides an environment that is conducive to bacterial growth. Water activity is a measure of the availability of water for microbial growth, and an Aw of 0.85 means that there is a significant amount of free moisture available.

Bacteria, particularly pathogenic organisms, require moisture to thrive and reproduce. When the water activity is at or above this level, it allows bacterial cells to absorb sufficient water, which is essential for their metabolic processes. This includes functions such as energy production, nutrient absorption, and cellular division.

In practical terms, foods with higher Aw values, such as fresh meats, fruits, and certain dairy products, are more likely to support rapid bacterial growth if they are not stored or handled properly. Therefore, maintaining appropriate storage conditions and monitoring the water activity of foods is crucial for food safety to prevent foodborne illnesses.

Understanding the relationship between water activity and bacterial growth is vital for food safety professionals, as it aids in making decisions about food preservation, storage, and handling practices.