Agriculture_Markets
Andrew M. Cuomo, Governor | Richard A. Ball, Commissioner
 
 

Water Activity

PRINCIPAL GROUPS OF FOODS BASED ON WATER ACTIVITY (aW)

  1. 0.98 aW and Above

    Fresh meats and fish
    Fresh fruits and vegetables
    Milk and other beverages
    Canned vegetables in brine
    Canned fruit in light syrup

    These are very moist foods, including those containing less than 3.5% sodium chloride or 26% sucrose in the aqueous phase. Food-poisoning bacteria and common spoilage microorganisms, with the exception of extreme xerophiles and halophiles, grow almost unimpeded at levels of aW within this range.

  2. Below 0.98 to 0.93 aW
    Evaporated milk
    Tomato paste
    Lightly salted fish, pork, beef products
    Canned cured meats
    Fermented sausages (not dried)
    Cooked sausages
    Processed cheese
    Gouda cheese
    Canned fruits in heavy syrup
    Bread
    High moisture prunes

    Maximum concentrations of salt or sugar in the aqueous phase of these foods will be near 10% and 50%, respectively. All known food-poisoning bacteria can grow at least in the upper part of this range.

  3. Below 0.93 to 0.85 aW

    Dry or fermented sausage (Hungarian, Italian type)
    Dried beef
    Raw ham
    Aged cheddar cheese
    Sweetened condensed milk

    This group includes foods with up to 17% salt or saturated sucrose in the aqueous phase. Only one bacterium known to cause food poisoning (Staphylococcus aureus), but many molds that produce mycotoxins, can grow in this aW range.

  4. Below 0.85 to 0.60 aW

    Intermediate moisture foods
    Dried fruit
    Flour
    Cereals
    Jams and jellies
    Molasses
    Heavily salted fish
    Meat extract
    Some aged cheeses
    Nuts

    No pathogenic bacteria grow within this range. Spoilage by xerophilic, osmophilic, or halophilic organisms can occur.

  5. Below 0.60 aW

    Confectionery
    Chocolate
    Honey
    Noodles
    Biscuits
    Crackers
    Potato chips
    Dried egg, milk, vegetables

    Microorganisms do not multiply below 0.60 aW, but can remain viable for long periods.