INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, ENZYMES, FLAVOUR
ENHANCERS, THICKENING AGENTS, AND
CERTAIN FOOD ADDITIVES
WHO FOOD ADDITIVES SERIES 6
The evaluations contained in this publication were prepared by the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
4-13 June 19741
World Health Organization Geneva 1975
1 Eighteenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557.
FAO Nutrition Meetings Report Series, 1974, No. 54.
MICROBIAL RENNET* (Endothia parasitica)
This enzyme preparation has been evaluated for acceptable daily
intake by the Joint FAO/WHO Expert Committee on Food Additives (see
Annex 1, Ref. No. 27) in 1971.
Since the previous evaluation additional data have become
available and are summarized and discussed in the following monograph.
The previously published monograph has been expanded and is reproduced
in its entirety below.
No information available.
Data are available for some commercial preparations.
Animal Route (mg/kg bw) Reference
Mouse Oral >5 000 Delahunt & Stebbins, 1965
i.v. 820 Delahunt & Stebbins, 1965
Rat Oral >2 000 Delahunt & Stebbins, 1965
i.v. 544 Delahunt & Stebbins, 1965
* This preparation is prepared from the species Endothia
Four groups of 10 male and 10 female rats received daily in their
diet for one year either 0, 8, 16 or 40 mg/kg bw of microbial rennet.
No adverse effects compared with controls were noted with regard to
survival, appearance, growth rate, food consumption, haematology,
urinalysis, serum chemistry, liver triglycerides, organ weights,
gross and histopathology (Delahunt & Stebbins, 1965).
Four groups of three male and three female beagles received daily
for one year an oral capsule with 0, 8, 16 or 40 mg/kg bw of microbial
rennet. There was no difference between controls and test groups
related to the administration of the test compound as regards
survival, appearance, behaviour, body weight, haematology, urinalysis,
serum chemistry, serum electrophoresis, neurological and
ophthalmological examination, organ weights, gross and histopathology
(Delahunt & Stebbins, 1965).
Microbial rennet was fed to groups of 20 male and 20 female rats
at a single level of 100 mg/kg bw in their diet for two years. No
contemporary controls were used. A style first generation was produced
as well. Neither the long-term study nor the multigeneration study
revealed any compound-related abnormalities (Mosinger, 1972).
The studies extending over one year in the rat and dog are
available for evaluation and do not reveal any adverse effects at
levels up to 40 mg/kg bw. A two-year single level study in rats did
not reveal any deleterious effects. This meets the requirements laid
down by the Committee. Chemical analysis for known microbial
metabolites in the final product failed to detect their presence.
Acceptable daily intake not specified.*
Delahunt, C. S. & Stebbins (1965) Unpublished report
Mosinger, M. (1972) Report submitted to WHO
* The statement "ADI not specified" means that, on the basis of the
available data (toxicological, biochemical, and other), the total
daily intake of the substance, arising from its use or uses at the
levels necessary to achieve the desired effect and from its acceptable
background in food, does not, in the opinion of the Committee,
represent a hazard to health. For this reason, and for the reasons
stated in individual evaluations, the establishment of any acceptable
daily intake (ADI) in mg per kg of body weight is not deemed