Dextrose Tryptone Agar (Dehydrated)

Detect and enumerate flat-sour thermophiles and mesophiles in food products with Thermo Scientific™ Oxoid™ Dextrose Tryptone Agar (Dehydrated). The medium, evolved as a result of several years of research by Williams¹ is most suitable for the cultivation and enumeration of the thermophilic bacteria causing flat-sour spoilage of canned food.

Canned foods are more often prone to flat sour spoilage due to contamination by either mesophilic or thermophilic aerobic spore formers.

Dextrose Tryptone Agar is a bacteriologically controlled medium for the detection and enumeration of thermophilic and mesophilic organisms in food products. Its use for routine cultural purposes is recommended by Cameron² and the Association of Official Analytical Chemist³. Dextrose Tryptone Agar is also recommended by:

1. Tanner⁴ for the examination of canned food, sugar, and starch for thermophilic bacteria of the Bacillusstearo thermophilus type (i.e. flat-sour spoilage bacteria).
2. The American Public Health Association⁵ for the enumeration of mesophilic and thermophilic aerobic bacteria in sweetening agents used in frozen dairy foods.
3. The National Canners Association6 for determination of the total plate and flat-sour count of thermophilic bacteria spores in ingredients, such as sugar and starch.
4. The American Public Health Association⁷ for the enumeration of mesophilic organisms and flat-sour spores in sugars, starches and other complex carbohydrates; and for the enumeration of flat-sour thermophiles in cereals and cereal products, dehydrated fruits and vegetables, and spices.
5. Baumgartner and Hersom⁸ for the examination of low and medium-acid canned food (above pH 4.5) for flat-sour thermophiles, mesophilic aerobes, and facultative anaerobes

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Remel™ and Oxoid™ products are now part of the Thermo Scientific brand