MICROBIOLOGICAL QUALITY OF SPRAY-DRIED PHARMACEUTICAL PLANT-EXTRACTS

Eighty-two spray-dried pharmaceutical plant extracts were analyzed in order to determine the profile of their microbial contamination. This profile seems to be qualitatively similar to that of the raw plant powders described in the literature. Quantitatively spray-dried extracts were less contaminated, but the total viable bacterial aerobic count remained relatively high, exceeding 10(3) CFU/g in 35 samples. The most frequently identified species were Gram-positive rods (56/82). Intestinal enterobacteria (growing at 44-degrees-C) were never displayed, but enterococci and group D streptococci were identified in 20 samples, and were considered as a better index of a faecal contamination. Staphylococcus aureus (1/82) and Pseudomonas aeruginosa (none) are unlikely contaminants for this kind of product. Moreover, in view of the low water content of the product (never exceeding 4%) the contaminating bacteria can be estimated to be in a static state. According to the observed profile of contamination, the original plant seems to be the main source of contamination of the spray-dried product. The spray drying process (including the extraction) insufficiently reduces this initial contamination. Thus efforts must be developed in order to optimize both the process and the selection, control and cleansing of the original material.