BAT Agar

BAT Agar

Cat. No. 1.07994.0500

For the detection of Alicyclobacillus in fruit juice.

Alicyclobacilli are aerobe, Gram-positive spore forming bacteria with an optimum growth at low pH value and elevated temperatures. Alicyclobacilli are spoilage ogranisms especially effecting the quality of fruit juices. (CERNY et al. 1984, BAUMGART and MENJE 2000)

The medium complies with the method described in the new IFU (International Fruit Union) Standard for the detection of Alicyclobacillus in fruit juices (2003).

Mode of Action	Typical Composition
Preparation	Application and Interpretation
Quality Control	Literature

Mode of Action
BAT agar supports the growth of Alicyclobacilli. The low pH-value in combination with the high incubation temperature inhibit growth of accompanying flora.

Typical Composition (g/liter)
Yeast extract 2.0; D(+) glucose 5.0; Calcium chloride 0.25; Magnesium sulfate 0.5; Ammonium sulfate 0.2; Potassium-dihydrogenphosphate 3.0; Agar-Agar 18.0.
Minerals mixture (already included in the medium):
Calcium chloride 0.00066; Zinc sulfate 0.00018; Copper sulfate 0.00016; Manganese sulfate 0.00015; Cobalt chloride 0.00015; Boric acid 0.00010; Sodium molybdate 0.00030.

Preparation
Suspend 29.0 g in 1 liter of purified water and heat to boiling until complete dissolved.

Note: The medium has a spontanous pH of 5.3 + 0.2 in order to maintain the gel strength during autoclavation. Adjust pH to 4.0 + 0.2 after autoclavation.

Autoclave (15 min at 121°C).

Cool to 45-50°C). Adjust pH to 4.0 + 0.2 by adding 1.7ml of sterile 1 N H₂SO₄. Mix well and pour plates.

pH: 4.0 + 0.2 at 25°C.

The prepared medium is clear and yellowish.

The prepared plates can be stored for up to 2 weeks at 2-8°C.

Keep protected from light and drying.

Application and Interpretation
Inoculate the plates by spreading 0.1 ml sample material on the surface.

The membranefilter method can be used for filterable sample material.

Incubation: 3-5 days at 45 + 1.0°C.

All colonies growing on the BAT agar are presumptive Alicyclobacilli and counted as such. Additional biochemical tests are necessary for confirmation.

Quality control

Test strains	Growth
Alicyclobacillus acidocaldarius DSMZ 446	Good
Alicyclobacillus acidoterrestris DSMZ 2498	Good
Alicyclobacillus cycloheptanicus DSMZ 4006	Good
Alicyclobacillus hesperidium DSMZ 12766	Good
Staphylococcus aureus ATCC 25923	None
Escherichia coli ATCC 25922	None

Literature

CERNY, G., W. HENNLICH und K. PORALLA. Fruchtsaftverderb durch Bacillen: Isolierung und Charakterisierung des Verderbserregers. - Z Lebens Unters Forsch 179; 224-227 (1984).
BAUMGART, J. and S. MENJE. The Impact of Alicyclobacillus acidoterrestris on the Quality of Juices and Soft Drinks. FRUIT PROCESSING 7; 251-254 (2000).
IFU Working Group Microbiology. First Standard IFU-Method on the Detection of Alicyclobacillus in Fruit Juices. April 2003.