Water Activity of Foods Table

Most microorganisms grow well at 0.91 to 0.99. Clostridium botulinum will grow and produce deadly botulism toxin if the pH is above 4.6 and the water activity is above 0.85.

Microorganisms grow at this aw and above 

Food examples

0.95 Pseudomonas, EscherichiaProteus,ShigellaKlebsiellaBacillusClostridium perfringens, some yeasts

Highly perishable foods (fresh and canned fruits, vegetables, meat, fish), milk, cooked sausages, breads, foods with up to 4 oz sucrose or 7% NaCl

0.91 SalmonellaVibrio parabaemolyticus,C. botulinumLactobacillus, some molds

Some cheese (Cheddar, Swiss, Provolone), cured meat, fruit juice concentrates with 55% sucrose or 12% NaCl

0.87 Many yeasts, Candida, Torulopsis, Hansenula micrococcus 

 Fermented sausage, sponge cakes, dry cheese, margarine, foods with 65% sucrose or 15% NaCl

0.80 Most molds, most Saccharomycesspp., DebaryomycesStaphylococcus aureus

Most fruit juice concentrates, condensed milk, syrup, flour, high-sugar cakes, pulses containing 15-17% moisture 

0.75 Most halophilic bacteria, Mycotoxigenic aspergilli

Jam, marmalade, glace fruits, marzipan, marshmallows 

0.60 Osmophilic yeasts, few molds
0.50
0.40

Dried fruits with 15-20% moisture, caramel, toffee, honey
Noodles with 12% moisture, spices with 10% moisture
Whole egg powder with 5% moisture 

 0.03

 Whole milk powder with 2-3% moisture, dehydrated soups

Source: Penn State University – Water Activity of Some Foods and Susceptibility to Spoilage by Microorganisms Adapted from Beuchat (1981).