Microbial Chart
"Water Activity of Some Foods and Susceptibility to Spoilage by Microorganisms"
Adapted from Beuchat (1981)
| aw | Microorganisms generally inhibited by aw at this point | Examples of foods within this range of water activity. |
| 0.950 | Pseudomonas, Escherichia, Proteus, Shigella, Klebsiella, Bacillus, Clostridium perfringens, some yeasts | Highly perishable foods (fresh and canned fruits, vegetables, meat, fish) and milk; cooked sausages and breads; foods containing up to 4oz (w/w) sucrose or 7%NaCl |
| 0.910 | Salmonella, Vibrio parahaemolyticus, C. botulinum, Serratia, Lactobacillus, Pediococcus, some molds, Rhodotorula, Pichia | Some cheese (Cheddar, Swiss, Muenster, Provolone); cured meat (ham); some fruit juice concentrates; foods containing 55%(w/w) sucrose or 12%NaCl |
| 0.870 | Many yeasts (Candida, Torulopsis, Hansenula), Micrococcus | Fermented sausage (salami); sponge cakes; dry cheese; margaring; foods containing 65% (w/w) sucrose (saturated) or 15%NaCl |
| 0.800 | Most molds (mycotoxigenic penicillia), Staphylococcus aureus, most Saccharomyces (baillii) spp., Debaryomyces | Most fruit juice concentrates; sweetened condensed milk; chocolate syrup; maple and fruit syrups; flour; rice; pulses containing 15-17% moisture; fruit cake; country style ham; fondants; high-sugar cakes |
| 0.750 | Most halophilic bacteria, mycotoxigenic aspergilli | Jam, marmalade; marzipan; galcé fruits; some marshmallows |
| 0.650 | Xerophilic molds (Aspergillus chevalieri, A. Candidus, Wallemia sebi), Saccharomyces bisporus | Rolled oats containing ~10% moisture; grained nougats; fudge marshmallows; jelly; molasses; raw cane sugar; some dried fruits; nuts |
| 0.600 | Osmophilic yeasts (Saccharomyces rouxii), few molds (Aspergillus echinulatus, Monascus bisporus) | Dried fruits containing 15-20% moisture; some toffees and caramels; honey |
| 0.500 | No microbial proliferation | Noodles, spaghetti, etc. containing ~12% moisture; spices
containing ~10% moisture |
| 0.400 | Whole egg powder containing ~5% moisture | |
| 0.300 | Cookies, crackers, bread crusts, etc. containing 3-5% moisture | |
| 0.030 | Whole milk powder containing 2-3% moisture; dried vegetables containing ~5% moisture; corn flakes containing ~5% moisture; dehydrated soups; some cookies and crackers |