FAO Nutrition Meetings
Report Series No. 48A
WHO/FOOD ADD/70.39
TOXICOLOGICAL EVALUATION OF SOME
EXTRACTION SOLVENTS AND CERTAIN
OTHER SUBSTANCES
The content of this document is the
result of the deliberations of the Joint
FAO/WHO Expert Committee on Food Additives
which met in Geneva, 24 June -2 July 19701
Food and Agriculture Organization of the United Nations
World Health Organization
1 Fourteenth report of the Joint FAO/WHO Expert Committee on Food
Additives, FAO Nutrition Meetings Report Series in press; Wld Hlth
Org. techn. Rep. Ser., in press.
ACTIVATED VEGETABLE CARBON (FOOD GRADE)
This material has been evaluated with specific reference to use as
filtering aids or clarifying agent
Biological data
Biochemical aspects
No information available.
Acute toxicity
No information available.
Short-term studies
Chicken
Groups of 20 one-day old chicks received a diet containing 0% or
2% charcoal for 34 days. No adverse effects other than those due to
physical adsorption on to the charcoal of the essential nutrients
vitamin A and K were seen. These effects could be reversed by
additional administration of these factors (Almquist & Zander, 1940).
Long-term studies
Mouse
Groups of 10-30, mostly male, occasionally female mice of either
CFW (white) or C3H (brown) strain were fed for periods of 12-18
months on diets containing 0% or 10% activated vegetable carbon. Diets
had either a water or oil emulsion base. Controls received 15% flour
using similar bases in their diet. No significant differences from
controls were reported. Similar groups of male mice received 10% of
benzene -extracted carbon black for 53-76 weeks. A number of tumours
appeared irregularly and unrelated to duration of treatment or dose,
probably due to contamination with carcinogenic extract.
Similar groups of 10-30 mice received 200 ppm or 800 ppm of
benzene - extracted material in their diet for 53-78 weeks. A
significantly raised incidence of gastro-intestinal malignant lesions
was found in test animals compared with controls. Lesions were similar
to those produced in positive controls given 200 ppm
methylcholanthrene in their diet (Nau et al., 1958).
Special studies
(a) Inhalation
Test groups of 60 guinea-pigs, 30 rats and 131 mice, with 22
guinea-pigs, 15 rats and 20 mice as controls were exposed to activated
vegetable carbon dust for 7 hours per day, 5 days per week, for 1
year. No significant effects were noted on mortality. At autopsy the
lungs showed evidence of multifocal dust deposition. Histopathology
showed dust deposits in alveoli with focal atelectasis and adjacent
alveolar overexpansion as well as interstitial pneumonitis. Mice
showed the least changes but rats had areas of lipid pneumonia. These
findings were consistent with inert dust reaction (Gross & Nau, 1967).
(b) injection
0.27 g of charcoal suspended in cottonseed oil was injected
s.c.into C3H Mice. After 16 months no gross or histopathological
changes were observed related to the injection. Cottonseed oil, used
to extract activated charcoal for either 30 or 90 days, was injected
s.c. into mice. After 20 months no significant gross or
histopathological changes were seen. 0.05-5 mg of benzene extract
suspended in cottonseed oil was injected s.c. into mice. After 13
months the only abnormal finding was a significant incidence of
glomerulonephritis in treated animals as compared with controls (Nau
et al., 1963).
Mice
A total of 2.9 g carbon black (suspended in mineral oil) or 3.2 g
(suspended in cottonseed oil) were brushed three times a week on to
the back of mice for 1 year. Animals were killed after 1 year or 16-17
months. No significant gross or histopathological changes were seen
compared with controls (Nau et al., 1963). 20% suspensions of
activated vegetable carbon in water or oil were painted in another
experiment three times per week on to the back of groups of 10-20 CFW
or C3H mice. After 12-17 months no abnormalities were seen in test as
compared with control groups (Nau et al., 1958a). Similar results were
obtained when benzene-extracted carbon black was used (Nau et al.,
1958a).
Benzene extract of activated vegetable carbon, suspended in water
or dissolved in benzene, was painted on to mice three times a week for
12-17 months. Results varied with the type of activated vegetable
carbon as regards local tumour formation but in a similar experiment
using food grade material no significant pathological changes were
seen (Nau et al., 1963; Nau et al., 1958a). Groups of 10 or 20 CFW or
C3H mice were painted 3 times a week for 12-17 months using 20%
suspensions of carbon black containing adsorbed methylcholanthrene in
water or oil. Positive controls were treated with methylcholanthrene.
Fewer tumours were produced in mice treated with carbon black
containing adsorbed methylcholanthrene compared with positive controls
observed for 12-18 months (Nau et al., 1958a).
Rabbit
Four rabbits were painted three times a week for 9-10 months with
20% suspensions of carbon black in water or oil, one animal was
treated for 23 months. No abnormal pathological findings were
observed. Another two rabbits were treated for 8-1/2 and 21 months
respectively with carbon black containing adsorbed 2000 ppm of
methylcholanthrene. No abnormalities were detected (Nau et al.,
1958a).
Monkey
Two monkeys were treated for 18 months with suspensions of carbon
black. One monkey was observed for an additional 13 months without
treatment. No abnormal pathological findings were seen (Nau et al.,
1958a).
Comments
The available ingestion studies referred only to mice and produced no
evidence that activated vegetable carbon exerted any adverse
biological effects in this species.
Evaluation
When used in accordance with good manufacturing practice as a
filtrating and clarifying agent no residues should result in food.
REFERENCES
Almquist, H. J. & Zander, D. (1940) Proc. Soc. exp, Biol. (N.Y.),
45, 303
Gross, P. & Nau, C. A. (1967) A.M.A. Arch. Eny. Hlth., 14, 450
Nau, C. A., Neal, J. & Stembridge, V. (1958) A.M.A. Arch. ind.
Hlth., 17, 20
Nau, C. A., Neal, J. & Stembridge, V. (1958a) A.M.A. Arch. ind.
Hlth., 18, 511
Nau, C. A. et al. (1963) Unpublished Report from Atlas Chemical
Company