Basically, in the EU we have the COMMISSION REGULATION (EC) No. 2073/2005 of 15 November 2005 on microbiological criteria for foodstuffs for the microbiological assessment of foodstuffs. (REG_2073/2005)
In addition, there are the microbiological guideline and warning values of the German Society for Hygiene and Microbiology (DGHM) e.V., which can be used as a recommendation.
USP 2023 also recommends microbiological limit requirements for non-sterile dietary supplements.
Recommended limits for herbal ingredients & products
Dried or powdered botanicals
Total aerobic plate count 10^5 CFU*/g or ml.
Total number of yeasts and molds 10^3 CFU*/g or ml.
Galletolerant, Gram-negative bacteria 10^3 CFU*/g or ml.
Absence of Salmonella spp. and E-coli in 10g.
Powdered plant extracts
Total aerobic plate count 10^4 CFU*/g or ml.
Total number of yeasts and molds 10^3 CFU*/g or ml.
Absence of Salmonella spp. and E-coli in 10g.
Food supplement with botanicals
Total aerobic plate count 10^4 CFU*/g or ml.
Total number of yeasts and molds 10^3 CFU*/g or ml.
Absence of Salmonella spp. and E-coli in 10g.
Recommended limits for dietary supplement ingredients & products
Other raw material and dietary supplement ingredients & dietary supplements with synthetic or highly refined ingredients.
Total aerobic plate count 10^4 CFU*/g or ml.
Total number of yeasts and molds 10^3 CFU*/g or ml.
Absence of Salmonella spp. and E-coli in 10g.