Development of Simple Differentiation Method between Guaiacol Producing and Non-guaiacol Alicyclobacillus
| Principal Investigator | Dr. Dong-Hyun Kang |
| Start
Date |
July 1, 2004 |
| Mission | Develop a simple internationally-respected method to test for bacteria that spoils pasteurized apple juice. |
Problem Addressed
In 1984, scientists identified Alicyclobacillus spp. as a spoilage organism in pasteurized apple juice. Spoilage cause by Alicyclobacillus spp. is difficult to detect. Most often, a spoilage incident is not recognized until the juice company receives consumer complaints. The spoilage is the result of guaiacol which is a substance which gives apple juice an off-flavor. Currently, apple juice companies are screening for the total number of contaminant Alicyclobacillus as an indicator of spoilage potential. There are over fifty strains of Alicyclobacillus. However, preliminary studies indicate that not all Alicyclobacillus spp. can produce guaiacol. Therefore, a simple test that could differentiate the guaiacol producing ability of Alicyclobacillus spp. is needed.
Goal
The goal of the project is to develop a simple colorimetric method to differentiate guaiacol producing Alicyclobacillus spp from non-guaiacol producing Alicyclobacillus spp.
Implications
According to the United States Department of Agriculture, the value of processed apple products was $207 million in 2003; apple juice or cider accounts for 79 percent of the $207 million ($163.53 million) and more than half (>$81.76 million) was produced by Washington State. As noted in a National Food Processors Association survey, 35 percent of manufacturers experience spoilage consistent with Alicyclobacillus spp. Most companies reported 1-2 incidents of spoilage within the past 5 years, with the spoilage rate at approximately 5 percent. Combining the results of these statistics, at least $0.41 million is lost as a result of Alicyclobacillus spp. spoilage in Washington State. Use of KV method can reduce the probability of apple juices with guaiacol producing Alicyclobacillus spp. to be sold on market, thus decreasing consumer complaints and financial losses. On the level of international marketing, use of the KV method can help in securing the quality of apple juice exports, increasing the competitiveness of U.S apple juices among apple juice exports of other countries.
Procedures
Procedure
Two chemical reactions are utilized for the KV method: (1) the decarboxylation
of vanillic acid to guaiacol by decarboxylase, and (2) formation
of brown pigments by the reaction between phenolic compounds and
peroxidase. Alicyclobacillus spp. with decarboxylase will
be able to convert the vanillic acid in KV broth to guaiacol and
result in color change from yellow to brownish red.
Techniques and Technologies Developed
The KV method was developed as a result of this project. KV broth with guaiacol-producing Alicyclobacillus spp. turned into a brownish red color whereas no color changes were observed with non-guaiacol producing Alicyclobacillus spp. Results obtained with the KV method were identical with olfactory results and was able to indicate whether or not the tested microorganism could produce guaiacol when olfactory results were uncertain. The KV method is the first method developed to test guaiacol producing ability of Alicyclobacillus spp. Because it is nearly impossible to eliminate the entry of Alicyclobacillus spp. into the juice manufacturing process, utilization of this method can allow quality control personnel to better estimate which products may potentially spoil and should not be sold or exported.
Publications/Journal Articles From Project
S. Chang. 2003. “Optimization of Alicyclobacillus spp. Isolation Procedures” (Master’s thesis), Washington State University.
S. Chang and D.-H. Kang, 2005. “Differentiation Method for
Guaiacol and Non-guaiacol Producing Alicyclobacillus spp.”
(in preparation).