Safety evaluation of certain food additives - ipcs inchem

114 PHOSPHOLIPASE C EXPRESSED IN PICHIA PASTORIS
In a 13-week study of general toxicity in rats, no significant treatment-related
effects were seen when the phospholipase C enzyme was orally administered at
doses of up to 2000 mg/kg bw per day by gavage. Therefore, the NOEL was
identified as 1672 mg TOS/kg bw per day, the highest dose tested. Phospholipase
C enzyme was not mutagenic in an assay for mutagenicity in bacteria in vitro and
was not clastogenic in an assay for chromosomal aberration in mammalian cells in
vitro. Similarly, an assay for micronucleus formation in mice showed no evidence
of a clastogenic effect in vivo.
4.3 Assessment of dietary exposure
An estimate of dietary exposure to phospholipase C was made by the
Committee based on the 13 cluster diets of the GEMS/Food categorization and on
the Concise European Food Consumption Database for the adult population (aged
16–64 years). The European database compiles mean and high percentiles of
individual food consumption for 15 broad food categories from the majority of
European countries (n = 17). The GEMS/Food database contains per capita daily
consumption of food commodities. In these estimates, reported consumption data
have been combined with the maximum use level recommended by the sponsor,
1000 mg of the commercial enzyme preparation (7% TOS content) per kilogram of
vegetable oil. For the GEMS/Food data, the food categories used in the calculation
were vegetable oils and fats, including olive, coconut, cotton seed, groundnut,
linseed, maize, palm kernel, rape seed, sesame seed, soya bean, sunflower and
other oils of vegetable origin, butter of karité and margarine). For the European
database, the food category used was the “fat products” category, including
mayonnaise, dressings, béchamel and hollandaise sauces, low-fat dressings or
mayonnaise, goose fat and coconut extract.
Mean consumption of vegetable oils ranged on average from 9 to 68 g/day
(GEMS/Food cluster diets; includes the range 21–59 g/day in Europe). For highpercentile
(95th percentile) consumers in Europe, consumption of vegetable oils
ranged from 51 to 150 g/day. If the enzyme is not removed from the oil and is used
at proposed levels, the potential mean dietary exposure to phospholipase C from
P. pastoris, assuming a body weight of 60 kg, would be 0.011–0.079 mg TOS/kg
bw per day, and the potential dietary exposure for high consumers would be 0.059–
0.175 mg TOS/kg bw per day.
5. EVALUATION
Comparing the conservative exposure estimates with the NOEL of 1672 mg
TOS/kg bw per day from the 13-week study of oral toxicity, the margin of exposure
is generally more than 10 000. The Committee allocated an acceptable daily intake
(ADI) “not specified” for phospholipase C expressed in P. pastoris, used in the
applications specified and in accordance with good manufacturing practice.