Method and kit for detection of guaiacol-producing bacterium
Disclosed is a method for detecting guaiacol-producing bacteria in a specimen comprising culturing the specimen or a dilution thereof on a plate of a solid medium for acidophilic bacteria comprising a compound represented by the following formula, wherein R is —H, —OH, —C(O)H, —C(O)CH 3 , —COOH, C 1 -C 3 alkyl or C 1 -C 3 alkenyl, wherein alkyl and alkenyl may optionally be substituted by —OH, —C(O)H or —COOH); and detecting a colony formed on the solid medium. According to preferred embodiments, the solid medium for acidophilic bacteria comprises 50 ppm or more of vanillic acid and the plate culture is carried out at 20° C. to 55° C. The present invention also provides a solid medium for acidophilic bacteria and a kit for detection of guaiacol-producing bacteria in a specimen. According to the present invention, guaiacol-producing bacteria present in a specimen such as fruit juice raw materials can be detected rapidly in a simple manner.
1. A method for detecting guaiacol-producing bacteria in a specimen comprising:
culturing the specimen or a dilution thereof on a solid medium for acidophilic bacteria, said medium comprising from 50 ppm to 225 ppm of vanillic acid, from 500 ppm to 1000 ppm of vanillin, or from 25 ppm to 50 ppm of ferulic acid; and
detecting a colony formed on the solid medium.
2. The method according to claim 1 , wherein the solid medium for acidophilic bacteria comprises from 50 ppm to 225 ppm of vanillic acid.
3. The method according to claim 1 , wherein the solid medium for acidophilic bacteria comprises from 50 ppm to 75 ppm of vanillic acid.
4. The method according to claim 1 , wherein the culturing step is carried out at 20° C. to 55° C.
5. The method according to claim 4 , wherein the culturing step is carried out at 27° C. to 33° C.
6. The method according to claim 1 , wherein the guaiacol-producing bacteria is thermotolerant acidophilic bacteria (TAB).
7. The method according to claim 1 , wherein the guaiacol-producing bacteria is bacteria belonging to the genus Alicyclobacillus.
8. The method according to claim 1 , wherein the guaiacol-producing bacteria is Alicyclobacillus acidoterrestris and/or Alicyclobacillus acidiphilus.
9. The method according to claim 1 , wherein the specimen includes fruit juice.
10. The method according to claim 1 , wherein the medium has a pH of from 3.0 to 4.0.
11. The method according to claim 1 , wherein the solid medium for acidophilic bacteria comprises from 50 ppm to 75 ppm of vanillic acid or 500 ppm to 900 ppm of vanillin.