Water activity: an extra barrier to microbial growth in sauces and dressings

Ranch dressing, nacho cheese sauce, chocolate syrup, and caramel dip all have high water activity values.  What keeps them microbially safe?  Combining good manufacturing practices with low pH, low water activity, or both.  

The primary quality measurement on sauces and dressings is usually pH. Many are acidic enough to control microbial growth without help from water activity.  Still, water activity can act as a secondary hurdle to microbial growth, providing an extra barrier against potential problems and allowing the means for gentler forms of preservation.

Low acid jams and jellies need water activity as a critical control point

Jams typically have a lot of sugar in them and, depending on the fruit ingredient, may also be acidic.  In less acidic jams, water activity acts as the critical control point because sugar’s ability to lower water activity prevents the growth of microorganisms.

Fast answers with no sample preparation

Quality control in sauces and dressings requires getting readings quickly, and confirming that products are in spec. The AQUALAB 4TE gives readings in under 5 minutes, without calibration or fussy sample prep.