Alicyclobacilli are aerobe, gram-positive spore forming bacteria, whose optimum of growth is at low pH value and increased temperatures. Alicyclobacilli are spoilage organisms especially effecting the quality of fruit juices. (CERNY et al. 1984, BAUMGART und MENJE 2000).
The Medium complies with First Standard IFU-Method on the Detection of Alicyclobacillus in Fruit Juices (2003).
Mode of Action
The BAT Medium supports the growth of Alicyclobacilli.The low pH-value in combination with the high incubation temperature inhibit the contaiminating flora in growth.
Typical Composition (g/litre)
Yeast extract 2.0; D(+)glucose 5.0; Calcium chloride 0.25; Magnesium sulfate 0.5; Ammonium sulfate 0.2; Potassium-dihydrogenphosphate 3.0; Zinc sulfate 0.00018; Copper sulfate 0.00016; Manganese sulfate 0.00015; Cobalt-chloride 0.00018; Boric acid 0.00010; Sodium molybdate 0.00030; Agar-Agar 18.0.
Dissolve 14.5 g in 500 ml of demin. water and heat to boiling until completely dissolved.
Note: he medium has a spontaneous pH of 5.3 ± 0.2 in order to maintain the gel strength during autoclavation. Adjustment of the pH to 4.0 ± 0.2 is made after the autoclavation.
Autoclave (15 min. at 121°C).
Cool to 45-50 °C. Adjust the pH to 4.0 ± 0.2 by adding 1 N H2SO4. Mix well and pour into sterile Petridishes.
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 medium by spreading 0.1 ml on the surface.
Membrane filter technique can be used with samples being filterable.
Incubation for 3-5 days at 45 ± 1.0 °C.
Count all colonies growing on the BAT Medium as suspicious Alicyclobacilli.
Confirm the suspicious colonies by further testing.