Cat. no. C5030 CRITERION™ APT Agar 122.4gm
Cat. no. C5031 CRITERION™ APT Agar 500gm
Cat. no. C5032 CRITERION™ APT Agar 2kg
Cat. no. C5033 CRITERION™ APT Agar 10kg
Cat. no. C5034 CRITERION™ APT Agar 50kg


Hardy Diagnostics CRITERION™ APT Agar is recommended for use in cultivating heterofermentative lactobacilli, Leuconostoc species, Lactococcus lactis and other microorganisms requiring a high thiamine content in meat products, tinned foods, fruit juices and other foodstuffs. In addition, it is used for maintaining stock cultures of Weissella viridescens ATCC® 12706 for use in the assay of thiamine.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.


APT Agar was first formulated by Deibel, Evans and Niven when they were investigating thiamine requiring bacteria and Evans and Niven for their study of heterofermentative lactobacilli that cause a faded or greenish discoloration on cured meats.(1,2) Bacteria that ferment lactic acid, Streptococcus, Leuconostoc, Pediococcus and Lactobacillus, are widespread in nature and commonly associated with food spoilage of dairy, meat and vegetable products.(3) Therefore, this media is recommended for the microbiological examination of canned meat, poultry, sauerkraut and other types of foods. Since APT Agar is non-selective, contaminants such as coliforms and many other types of common bacteria will grow readily on this medium. For accurate results, APT Agar should be used according to the procedures listed in the Compendium of Methods for the Microbiological Examination of Foods by the American Public Health Association (APHA).(3)

Hardy Diagnostics CRITERION™ APT Agar contains metallic salts that provide ions used in lactobacilli replication. Peptones supply essential amino acids, minerals and nitrogenous compounds. Dextrose provides an energy source. Yeast extract enhances bacterial growth and supplies B-complex vitamins. Sodium chloride is added to maintain osmotic equilibrium. Tween® 80, also known as Polysorbate 80, is a source of fatty acids required by lactobacilli.


Gram weight per liter: 61.2gm/L
Casein Peptone 12.5gm
Dextrose 10.0gm
Yeast Extract 7.5gm
Sodium Chloride 5.0gm
Sodium Citrate 5.0gm
Dipotassium Phosphate 5.0gm
Magnesium Sulfate 0.8gm
Tween® 80 0.2gm
Manganese Chloride 0.14gm
Ferrous Sulfate 0.04gm
Thiamine Hydrochloride 0.001gm
Agar 15.0gm

Final pH 6.7 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.


Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original light beige.

Store the prepared culture media at 2-30ºC.



1. Suspend 61.2gm of dehydrated culture media in one liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat to boiling for 1 minute to dissolve completely. DO NOT OVERHEAT.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC. and dispense as desired into sterile containers.


For information on procedures and interpretation of results, consult listed references.


Because APT media is non-selective and permits the growth of contaminants, it is recommended that biochemical and/or serological tests be performed on colonies from pure culture for complete identification and to confirm the presence of lactobacilli.


Standard microbiological supplies and equipment such as loops, swabs, other culture media, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Lactobacillus fermentum
ATCC ® 9338
A 24-48hr 35°C Aerobic Growth

User Quality Control

Physical Appearance

Hardy Diagnostics CRITERION™ APT Agar powder should appear homogeneous, free-flowing, and light beige in color. The prepared media should appear slightly opalescent and medium amber in color.


1. Evans, J.B., and C.F. Niven, Jr. 1951. Nutrition of the heterofermentative lactobacilli that cause greening of cured meat products. J. Bacteriol.; 62:599-603.

2. Deibel, R.H., J.B. Evans, and C.F. Niven, Jr. 1957. Microbiological assay for thiamine using Lactobacillus viridescens. J. Bacteriol.; 74:818-821.

3. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

4. Association of Official Analytical Chemists. Official Methods of Analysissm, AOAC, Washington, D.C.

5. The Official Compendia of Standards. USP-NF. United States Pharmacopeial Convention, Rockville, MD.

6. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

7. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA.

ATCC is a registered trademark of the American Type Culture Collection.
Tween is a registered trademark of ICI Americas, Inc.