Toxicological evaluation of some food
additives including anticaking agents,
antimicrobials, antioxidants, emulsifiers
and thickening agents
WHO FOOD ADDITIVES SERIES NO. 5
The evaluations contained in this publication
were prepared by the Joint FAO/WHO Expert
Committee on Food Additives which met in Geneva,
25 June - 4 July 19731
World Health Organization
Geneva
1974
1 Seventeenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 539;
FAO Nutrition Meetings Report Series, 1974, No. 53.
AMMONIUM SALTS OF PHOSPHATIDIC ACIDS
Explanation
These compounds have been evaluated for acceptable daily intake
by the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1;
Ref. No. 20) in 1969.
The previously published monograph has been revised and is
reproduced in its entirety below.
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
These compounds were readily absorbed from the rat
gastrointestinal tract in the presence of fats without changes in fat
absorption or gastrointestinal function (Frazer, 1954). No in vitro
haemolytic effect was seen with this product nor was it any stronger
than natural lecithin (Frazer, 1954). Incubation of the ammonium salt
of 32P-phosphatidic acid with simulated gastric juice, homogenate of
intestinal mucosa, trypsin or chymotrypsin in vitro resulted
in the liberation of inorganic phosphate. The ammonium salt of
32P-phosphatidic acid was given to eight male and seven female rats at
a level of 60 to 30 mg/kg bw. Urine and faeces were collected at
intervals of one, two, four, six, seven and 24 hours and at 10 and 16
days after administration rats were killed for examination. Similarly,
inorganic phosphate labelled with 32P was given to three male and
three female rats by intubation and rats were killed one, two
and four hours after administration. Many organs were examined for
radioactivity. In addition, incorporation of 32P into phospholipids of
tissues at various intervals after dosing was determined. Percentage
recoveries after 24 hours were 91.4% males, 91.9% females, after 16
days 93.4% males, 98.1% females. Thus 79% of the labelled material was
excreted in the faeces within 24 hours while some 4% was eliminated in
the urine. The remaining 17% were stored in bone and muscle as
inorganic phosphate and phosphate ester while the rest of the tissue
contained oily traces mostly in the phospholipid fraction. Comparison
with uptake of labelled inorganic phosphate showed similar
distribution of the phosphate to bone, muscle, liver, gut content
and urine. The radioactive phospholipid fraction present in the rat
four hours after administration was found to be nearly identical
whether 32P was administered as phosphatidic salt or as inorganic
orthophosphate. The radioactive phospholipid fraction in the liver
of test rats was chromatographically identical with the liver
phospholipid of rats fed 32P orthophosphate. The observed tissue
radioactivity is due to breakdown to inorganic phosphate which enters
the phosphate and phospholipid pools. There was no evidence of storage
in tissues of any P containing moiety of the phosphatidic salt. The
triglyceride moiety was probably hydrolyzed and absorbed by normal
physiological routes (Feuer, 1967).
TOXICOLOGICAL STUDIES
Acute toxicity
LD50 Reference
Animal Route (mg/kg bw)
Rat Oral 5 000 Frazer, 1954
Rat I.m. 2 000 Frazer, 1954
Guinea-pig I.m. 2 000 Frazer, 1954
Rabbit Oral 5 000 Frazer, 1954
Dog Oral 2 000 Frazer, 1954
No abnormal pathological findings or behaviour patterns were seen
(Frazer, 1954).
Short-term studies
Rat
After twice-weekly intraperitoneal injections in rats of 2 g /kg
for five weeks, there was no deleterious effect on growth, relative
spleen weight, haematology or corpuscular fragility (Gaunt et al.,
1967).
Groups of 15 male and 15 female rats each received diets
containing 0%, 0.75%, 1.5%, 3.0% and 6.0% of the compound for 90 days.
No adverse effects were seen on appearance, growth, food consumption,
haematological indices, liver and kidney function, relative organ
weights and gross and histological appearance of the organs. Similar
results were obtained in rats given a dietary level of 6% soya
lecithins for 90 days except that a slight transient anaemia was seen
in females (Gaunt et al., 1967).
Groups of 50 rats each received 0%, 1% or 2.5% compound in their
diet for 45 weeks. No adverse effects were seen with regard to
mortality, weight gain, liver function, kidney function and
histopathology in test groups compared with controls (Frazer, 1954).
Long-term studies
None available.
Comments:
The biochemical studies show that the ammonium salts of
phosphatidic acids break down into normal food constituents. The
available rat studies show this material to be non-toxic at the level
of 6% in the diet, the highest concentration tested. Because of the
possible substantial intake of this material by children it is
necessary to have a long-term study on one species and desirable to
determine the metabolic fate in man. A long-term study in the rat is
now in progress.
EVALUATION
Level causing no significant toxicological effect
Rat: 60 000 ppm (6%) in the diet equivalent to 3000 mg/kg bw.
Estimate of acceptable daily intake for man
0 to 15 mg/kg bw.*
FURTHER WORK OR INFORMATION
Required (by June 1974): Submission of the results of the long-
term study in the rat and metabolic studies in several species.
Desirable: Studies on the metabolic fate of these compounds in
man.
REFERENCES
Feuer, G. (1967) Fd Cosmet. Toxicol., 5, 631
Frazer, A. C. (1954) Unpublished report dated July 1954
Gaunt, I. F., Grasso, P. & Gangolli, S. D. (1967) Fd Cosmet. Toxicol.,
5, 623
* Temporary.