Ranch dressing, nacho cheese sauce, chocolate syrup, and caramel dip all have high water activity values. What assures their safety? Combining good manufacturing methods with either low pH or water activity (or both). The foremost quality measurement on sauces and dressings is usually pH, and many are acidic enough to hinder microbial growth without help from water activity. However, water activity can still act as a hurdle to hinder microbial growth, providing extra protection against potential problems.
ADDITIONAL INFORMATION
Nuts & Dried Fruit
Dried fruit and nuts are sometimes consumed together as a product named: “trail mix”. That’s not the only reason these two products fall in the same category on this page. Dried fruit and nuts are both natural products that normally undergo post-harvest processing before they are sold to consumers. Moisture mistakes for both these products are similarly painful: too much water causes mold; too little equates to lost profit, not to mention quality problems.
Coffee & Tea
Freeze-dried to fresh-brewed, coffee and tea are manufactured in a variety of different ways. Moisture has always been a thought in determining how long to dry or roast them. However, measuring moisture alone in tea and coffee leaves much to be desired. If a buyer of Ethopian coffee specifies green beans at 12% moisture, someone will probably check the shipment before it’s sent. But how do they know that their 12% and their supplier’s 12% are equivalent?
Cereal & Grain Products
From spagetti to Special-K, cereal and grain products are a large portion of processed food. Many food companies use moisture content as a quality spec and have for many years. They don’t measure water activity if their products are considered “dry enough” that mold/bacteria aren’t viable concerns for them.
Candy & Confectionary
What’s the best way to monitor water in moisture sensitive candy?
Snack Foods
Lipid oxidation often reduces shelf life for snacks. It’s becoming a bigger problem for snack food makers as they switch to healthier oils, which are more prone to oxidation.
Processed & Cured Meats
Microbes often get a bad rap. Good bacteria get lumped in with harmful ones like botulism and salmonella. The unique tangy flavor of a good salami is a product of fermentation bacteria. Reactions like this show that making good food is a complex balancing act – if your water activity is too high, your product will eventually succumb to the bad microbes, but if it’s too low, the good ones will never work their magic.