What type of test measures the water activity of food?

The correct answer, which is the Aw meter, specifically measures the water activity in food products. Water activity (aw) is a critical parameter in food science because it indicates the availability of water for microbial growth, enzymatic reactions, and chemical reactions. It is an important factor in determining the shelf life and safety of food products.

Unlike moisture analyzers, which measure the actual moisture content (the amount of water present), the Aw meter assesses how much of that water is available for biological functions. This distinction is vital in food preservation and safety; for instance, foods with low water activity require different preservation methods compared to those with high water activity.

pH meters focus on measuring the acidity or alkalinity of a solution, which, while important in certain contexts, does not provide information about water availability. Similarly, texture analyzers evaluate the physical properties of food, such as hardness and firmness, but do not address moisture availability or water activity levels. Thus, the Aw meter is uniquely suited for this specific purpose in food science.