Guaiacol producing Alicyclobacillus spp. - differentiation, detection, and control

Alicyclobacillus spp. are thermoacidophilic sporeformers that have significant impact on the pasteurized juice industry. Better detection and control methods are needed to minimize Alicyclobacillus related spoilage. The objective of this research is to improve existing detection and control methods by (1) the investigation of basic characteristics of guaiacol producing Alicyclobacillus and development of a novel detection method; and (2) the evaluation of Alicyclobacillus control method during storage and processing.;Differences in growth characteristics were observed but not significant between guaiacol producing and non-guaiacol producing Alicyclobacillus . Enzyme and carbohydrate utilization profiles were variable depending on test isolates. Guaiacol formation was detectable within 12 h at 43°C and further accelerated under microaerophilic conditions. The newly developed SK2 agar provides selective identification of guaiacol producing Alicyclobacillus with a 95% correct identification rate. SK2 agar is the first known media providing selective isolation of guaiacol producing Alicyclobacillus. The effectiveness of aqueous and gas chlorine dioxide against Alicyclobacillus spores has been demonstrated. Greater than five log reductions were observed following 1 min and 1 h exposures to 120 ppm ClO2(aq) and 4.32 ppm ClO2(g), respectively.