Two main groups of bacteria, classified as Gluconobacter and Lactobacillus, are present in ripening honey. A third bacterial group, classified as Zymomonas, and several types of yeast are occasionally isolated. Both in natural honey and in synthetic syrup the bacterial population decreases in the course of the ripening process. Lactobacillus and Gluconobacter disappear after minimum moisture (about 18%) is reached, but the former does so sooner than the latter. The presence of these bacteria in different parts of the bee has been also investigated.