NEW (Unpublished work June 2018) We have challenge tested fresh juices with E. coli O157:H7 added to raw kombucha. Greater than 5 logs of 5 strains of E. coli O157:H7 were added to fresh fruit juice. The juice was added to raw kombucha with pH levels from 2.8 – 3.4. The beverage was immediately carbonated and stored at 5C. Unfortunately, after 2 weeks there was only a 2-3 log drop in the E. coli numbers. This study suggests that the acids that drop the pH in raw kombucha and/or fruit acids are not sufficient to effect a 5 log reduction at refrigeration temperatures.
NEW The AOAC has a new proposed method to measure alcohol in Kombucha. AOAC link.