Thermoacidurans Agar, is a specialized medium designed for isolating and cultivating Bacillus coagulans (formerly Bacillus thermoacidurans) from food products. This medium is also effective in isolating mesophilic spore-forming anaerobes like Clostridium spp. from various food items. It is particularly useful in detecting spoilage in canned tomato products and dairy products.
Composition and Principle
The Thermoacidurans Agar comprises Yeast Extract, Peptone, Glucose, Dipotassium Phosphate, and Agar. The Yeast Extract and Peptone provide necessary nutrients, including nitrogen, carbon, and vitamins, which facilitate bacterial growth. Glucose acts as the carbohydrate source, while Dipotassium Phosphate serves as a buffer. Agar is the solidifying agent. The formulation aims to create an environment conducive to the growth of Bacillus coagulans and other similar bacteria. The final pH of the medium is 5.0 ± 0.05 at 25°C, ideal for the growth of these acid-tolerant organisms.
To prepare the medium, 39.0 g of the powder is suspended in 1 liter of distilled or deionized water. The solution is heated until completely dissolved and then sterilized in an autoclave at 121°C for 15 minutes.
The medium is inoculated with the sample to be examined and incubated at 55 ± 1°C for 18-48 hours. This incubation temperature is optimal for the growth of Bacillus coagulans.
Interpretation of Results
After incubation, growth of microorganisms is observed. It is important to note that microorganisms other than B. coagulans may grow on this medium. Therefore, further microscopic examination and biochemical tests are necessary to identify the organisms to the genus and species level.
The dehydrated medium is very hygroscopic and should be stored at 10-30°C in a dry environment in its original container, tightly closed. The prepared medium should be stored at 2-8°C.
Warnings and Precautions
While Thermoacidurans Agar is not classified as hazardous, it is recommended to consult the Safety Data Sheet for correct use. The product must be used only by properly trained operators.
Thermoacidurans Agar is a vital tool in the microbiological analysis of food, especially in detecting spoilage organisms like Bacillus coagulans. Its specific formulation, ease of preparation, and ability to support the growth of target microorganisms make it an essential medium in the food safety testing laboratories, particularly in the canned food and dairy industries.