Most species can grow in the pH 2.0-6.0 range, and none have been shown to grow above pH 6.5. disulfidooxidans is the only psychrotroph, being able to grow at 4 ☌. A. acidocaldarius is the most thermotolerant, as is able to grow in temperatures up to 70 ☌. The exceptions include A. acidocaldarius (65 ☌), A. Most Alicyclobacillus species optimally grow in the 40-55 ☌ range. pohliae were originally classified in genus Alicyclobacillus, but were later reclassified into the novel genus Effusibacillus in 2014. Not all Alicyclobacilli produce guaiacol, and thus not all species are of spoilage concern. Alicyclobacilli have been implicated in spoilages of pear, orange, peach, mango, and white grape juice, fruit juice blends, and tomato products. When a product is spoiled by Alicyclobacillus, the juice products develop a disinfectant-like odor and/or flavor (due to guaiacol production), but the bacteria do not cause swelling of the package or discoloration of the product, nor is it pathogenic to humans. Alicyclobacilli are of special interest to the fruit juice canning industry because common pasteurization techniques (92 ☌ for 10 seconds) do not deactivate the spores Alicyclobacillus species can have a D 95-value of over 8 minutes (requiring treatment of over 8 minutes at 95 ☌ to kill 90% of spores). The bacteria are able to grow in acidic conditions, while the spores are able to survive typical pasteurization procedures.Īlicyclobacilli are strictly aerobic, acidophilic, mesophilic to thermophilic, soil-dwelling organisms. Alicyclobacillus is a genus of Gram-variable, rod-shaped, spore-forming bacteria.
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