Safety evaluation of certain food additives - ipcs inchem

178 POLYDIMETHYLSILOXANE (addendum)
ADI of 0–0.8 mg/kg bw (see section 5), respectively; for 90th-percentile consumers,
potential dietary exposures were 66% and 43% of the temporary ADI, respectively.
Potential mean dietary exposures to PDMS for European countries were similar to
those for Australia and New Zealand, although somewhat higher (potential mean
dietary exposure, 28–49% of the temporary ADI; high consumers’ dietary exposure,
65–138% of the temporary ADI).
The limited data available indicate that there may be potential to exceed the
temporary ADI for high consumers of PDMS; however, all dietary exposures are
likely to be overestimates, as maximum levels of use for PDMS were assumed and,
for the European countries, it was assumed that PDMS was used in broader food
categories than those listed in the GSFA. In reality, this is unlikely, as alternative
food additives will be used in some foods, and use levels may be lower than the
acceptable maximum level.
4. COMMENTS
4.1 Toxicological data
Orally administered [ 14C]PDMS with viscosities of 350 cSt and 10 cSt were
excreted unchanged in the faeces, with little, if any, absorption.
Ocular lesions were consistently observed in the available short-term and
long-term studies of toxicity with PDMS given by oral administration in the diet or
by gavage. Dose-related ocular lesions (corneal opacities/crystals, granulomatous
inflammation and suppurative inflammation of the corneal epithelium) were
observed in 28-day and 13-week studies in F344 rats given 10 cSt and 350 cSt
PDMS.
In the long-term study with 10 cSt PDMS in F344 rats, corneal opacity was
observed at slightly increased incidences in males at 1000 mg/kg bw per day and
in females at 100 or 1000 mg/kg bw per day. Corneal opacity usually correlated
with the microscopic finding of keratitis or the incidental microscopic finding of
corneal dystrophy. Inflammation of the nasolachrymal duct was observed with
slightly increased incidence and severity in males at 1000 mg/kg bw per day. Food
consumption, body weight gain, haematology and serum parameters were
unchanged in all the groups treated with PDMS compared with the control group,
and no other adverse effects were observed in short-term or long-term studies.
4.2 Assessment of dietary exposure
PDMS is used as an antifoaming agent in fruit and vegetable juices, an
anticaking agent in confectionery and flour products, and an emulsifier in edible oils
essentially free of water. It is included in the current version of the GSFA for use in
a wide range of foods at acceptable maximum levels of 10–110 mg/kg food.
Budget method calculations indicate that the use of PDMS in solid food and
beverages at the GSFA acceptable maximum levels may result in the temporary
ADI of 0–0.8 mg/kg bw established at the present meeting (see section 5) being
exceeded, assuming use in 25% of solid food and 25% of beverages. Hence, data