FAO Nutrition Meetings
Report Series No. 40A,B,C
WHO/Food Add./67.29
TOXICOLOGICAL EVALUATION OF SOME
ANTIMICROBIALS, ANTIOXIDANTS, EMULSIFIERS,
STABILIZERS, FLOUR-TREATMENT AGENTS, ACIDS AND BASES
The content of this document is the result of the deliberations of the
Joint FAO/WHO Expert Committee on Food Additives which met at Rome,
13-20 December, 19651 Geneva, 11-18 October, 19662
1 Ninth Report of the Joint FAO/WHO Expert Committee on Food
Additives, FAO Nutrition Meetings Report Series, 1966 No. 40;
Wld Hlth Org. techn. Rep. Ser., 1966, 339
2 Tenth Report of the Joint FAO/WHO Expert Committee on Food
Additives, FAO Nutrition Meetings Report Series, 1967, in press;
Food and Agriculture Organization of the United Nations
World Health Organization
1967
HYDROCHLORIC ACID
Chemical name Hydrochloric acid
Empirical formula HCl
Molecular weight 36.46
Definition Hydrochloric acid contains not less than the
minimum amount of hydrogen chloride specified.
NOTE - Hydrochloric acid produced during the
manufacture of chlorinated hydrocarbon
insecticides is not considered to be of food
grade quality and is not suitable for use in
food processing.
Description Hydrochloric acid is a colourless liquid; it
has a pungent odour if the concentration is
about 25 per cent. When well diluted with
water it has an acid taste.
Use As an acidulant.
Biological Data
Biochemical aspects
The constituent ions of hydrochloric acid are normal participants
in animal and human metabolism and, per se, of no toxicological
significance. Toxicological considerations are involved either in the
purely local action of the corrosive acid or in the effects of the
addition of large quantities of either hydrogen or chloride ions to
the electrolyte pool of the body. The hydrolytic action of
hydrochloric acid on food substances is similar, in principle, to that
of the acid occurring in normal gastric juice. In addition,
hydrochloric acid regulates the pepsin activity of gastric juice
(LeVeen, 1947). Physiological investigations also ascribe to
hydrochloric acid a role in controlling the tone of the pylorus, and
thus the rate of gastric emptying, as well as the amount of acid
secretion in the stomach.
Acute toxicity
Animal Route LD50 References
(mg/kg
body-weight)
Rabbit Intragastric 900 Loewy & Munzer, 1923
No formal acute toxicity tests are available. Oxygen consumption
and carbon dioxide production in rabbits given half the LD100 showed a
variable but definite reduction for at least 24 hours, considerably
beyond the probable period necessary for recovery from the acidotic
effect of the acid ingestion, thus pointing to a systemic metabolic
effect in corrosive acid poisoning (Loewy & Munzer, 1923)
The effect in man of accidental or suicidal intake of
concentrated 35-40 per cent. hydrochloric acid are well known and
there are numerous reports in the medical literature. Intakes of 300
ml concentrated hydrochloric acid appear to be fatal (Kremser, 1957)
but persons having swallowed 20-100 ml have been reported to recover
(Franzen, 1957; Hangleiter, 1939; Koberg, 1954; Kremser, 1957;
Stratford, 1920; Tucker & Gerrish, 1960). Similar recoveries after
taking large quantities of dilute acid (120 and 180 ml) have been
reported (Marks et al., 1963).
Short-term studies
Rat. Groups of 10-60 rats were fed for 16 days on basal diets
and drinking water containing 0.3 per cent. acid, 0.3 per cent. acid
plus 20 per cent. pepsin, and 20 per cent. inactivated pepsin plus 0.1
per cent. acid. One set of groups was fasted for 48 hours before,
being allowed access to food and fluid on the third day and this cycle
was repeated 5 times. All groups receiving acid in their drinking
water developed peptic ulcer-like lesions if subjected to fasting, but
no lesions were seen in the non-fasting group on 0.3 per cent. acid
and the control groups. Histologically there was focal gastric
submucosal oedema with extension to the epithelium and muscle layer
with inflammatory cellular infiltration and ulceration (Matzner &
Windwer, 1937).
Observations in man
Prolonged exposure to low concentrations of gaseous hydrochloric
acid leads to erosion of teeth; exposure to acid mist produces
bleeding nose and gums with ulceration of oral and nasal mucosa and
tender facial skin (Patty, 1962).
Comments
In concentrations approaching the physiological pH of gastric
juice hydrochloric acid is probably of no toxicological significance.
Evaluation
There appears to be no need to limit on toxicological grounds the
use of hydrochloric acid in accordance with good manufacturing
practice.
REFERENCES
Franzen, J. (1957) Med. Klin., 19, 816
Hangleiter, H. (1939) Sammlg von Vergiftungsfallen, 10, 195
Koberg, H. (1954) Fortsch. Rontpr., 80, 784
Kremser, K. (1957) Zentralbl. Chir., 34, 1435
LeVeen, H. H. (1947) Gastroent., 8, 648
Loewy, A. & Munzer, E. (1923) Bioch Z., 134, 437
Marks, I. N., Bank, S., Werbeloff, L., Farman, J. & Louw, J. H. (1963)
Amer. J. Dig. Dis., New Series, 8. 509
Matzner, M. J. & Windwer, C. (1937) Amer. J. Dig. Dis., 4, 180
Patty, F. A. (ed.) (1962) Industrial Hygiene and Toxicology, 2,
851
Stratford, H. (1920) Brit. Med. J., ii, 164
Tucker, A. S. & Gerrish, E. W. (1960) J. Amer. Med. Ass., 174, 890
See Also:
Toxicological Abbreviations
HYDROCHLORIC ACID (JECFA Evaluation)
Hydrochloric Acid (IARC Summary & Evaluation, Volume 54, 1992)