We received a memorandum from the Manufactured Foods Division of the Ministry of Food requesting our advice on a proposal to make an Order prescribing maximum limits for the fluorine content of calcium acid phosphate A.C.P. sold for use in food, and certain articles containing it. The memorandum stated that two processes are used for the manufacture of A.C.P. In the first process elementary phosphorus is used as the raw material and the product is of a high degree of purity. Something like 80 per cent. of the total output in the country is made in this way. In the alternative process the raw material is rock phosphate and the product is contaminated with compounds of fluorine. We were informed that manufacturers using this process claim that they have been selling A.C.P. containing as much as 3,000 p.p.m. of fluorine for many years without exception being taken by Food and Drugs Authorities. During the last few years these manufacturers have had to use such rock phosphates as have been available and no doubt the resulting A.C.P. has often been more heavily contaminated than it was before the war. We were also informed that the possibility of harmful contamination of foods with fluorine has been giving concern to Public Health Authorities. From 1942, Food and Drugs Authorities brought proceedings in certain cases under the Food and Drugs Act, 1938, in respect of baking powder or articles containing it contaminated with fluorine, but they failed in some of them to obtain conviction. In August, 1943, the Society of Public Analysts and Other Analytical Chemists, which had been giving consideration to this question, issued a statement recommending that no action should be taken under the Food and Drugs Act where the following proportions of fluorine, however combined, were not exceeded In acid phosphates, 200 parts per million in baking powder, 70 parts per million in golden raising powder, 50 parts per million in selfraising flour, cake mixtures and like compositions, 5 parts per million. Nevertheless, in the absence of a legal standard it is difficult to convince a Court that where any of these proportions is exceeded an offence has been committed. In at least one case subsequently a Food and Drugs Authority failed to secure a conviction and in general Authorities appear to have been reluctant to take action. In view of this unsatisfactory situation, several Authorities have proposed that limits should be defined by Regulation. Manufacturers have also urged that steps should be taken to clarify the position, and at our invitation the manufacturers submitted a report of work carried out on their behalf by H.E. Archer, M.R.C.S., L.R.C.P., F.R.I.C, and B. Leech, M,A., F.R.I.C. In this report it was suggested that i In the combination in which it occurs in food products after aerating ingredients have interacted, fluorine is insoluble in normal gastric juice even when the acidity approaches the upper limit of normality. Further, phosphates present in a food after interaction of the aerating ingredients buffer the gastric juice at a pH on the alkaline side of neutrality so that any fluorine present is insoluble and unabsorbable. ii Within the limits of experimental error, any fluorine ingested in the form of baking powder containing contaminated A.C.P. after interaction of the aerating ingredients is excreted completely in the faeces. The report was discussed at a meeting between the manufacturers representatives and the committee. We pointed out that since the experiments described related to only one adult, who was on a high milk diet, the results could not be accepted as evidence of what might take place in the case of other persons, especially children, taking a more varied diet. Dr. Archer, however, indicated that the case for the harmlessness of fluorine rested not merely on the experiments described in the report, which he recognised as being chiefly of a confirmatory nature, but also on the fact that mottling of teeth is rarely or never found except where the water supply is known to be contaminated. He asserted that this condition was a highly sensitive indicator of fluorine absorption, and since A.C.P. contaminated with fluorine was extensively used, the absence of mottling of teeth showed that fluorine was not absorbed from A.C.P. It was further asserted that even if widespread mottling had occurred, the condition was to be regarded merely as a cosmetic disability and not as evidence of the toxicity of fluorine. Reference was made to work by Roholm stated to show that cryolite workers enjoyed excellent health and that comparatively large amounts had to be ingested daily for many years before any symptoms developed. It was stated further that investigations in this country had failed to reveal any radiological evidence of skeletal changes in either adults or children with mottled teeth, except in undernourished children from bad homes. The manufacturers' case therefore was the fluorine was not absorbed from A.C.P., and even if absorbed was harmless. On the other hand, our attention was drawn to various statements in medical literature suggesting that mottling of teeth is more common than usually supposed. Moreover, with other toxic elements, for example lead, almost complete excretion in the faeces does not necessarily justify the assumption that oral ingestion is harmless. We felt that the arguments advanced by the manufacturers could not be dismissed without further investigation and that their validity could be assessed only by persons having the requisite physiological and toxicological knowledge. The following questions were accordingly addressed to the Medical Research Council 1 Is there any authoritative evidence that injury to human health has resulted from the absorption over lengthy periods of small amounts of fluorine from food other than water 2 Is it true that widespread mottling of teeth in the community does not occur 3 If the answer to question 2 above is in the affirmative, can the absence of widespread mottling be accepted as evidence that absorption does not occur at all or not to any harmful extent 4 Having regard to the available evidence, including that advanced in the report prepared by Dr. Archer and Mr. Leech, is it in the opinion of the council desirable that an Order should be made limiting the amount of fluorine in calcium acid phosphate 5 If the answer to question 4 is in the affirmative, what limit should be imposed The following specific answers were given to these questions 1 Answer is no, because so far no one would have recognised the effects of such ingestion analysts have only been interested in fluorine determinations in recent years and pathologists have not clearly established the criteria of milder forms of chronic fluorosis. 2 Answer is no in any case mottling of enamel is not the most suitable indication of fluorine ingestion except by the water supply. 3 Animal experiments have shown that fluorine is ingested by pigs, rabbits, rats, cattle, sheep and dogs from food, pasture and rock phosphates. Widespread fluorosis occurs in cattle and humans in Algeria, one of the regions from which much rock phosphate is obtained. The ingestion of fluorine from rock phosphates, besides producing the wellknown bone changes, produces in different species different effects, including pathological changes in the mucous membrane of the alimentary canal, and nephrosis. 4 Yes, an Order should be made. 5 The limit for calcium acid phosphate should be 300 p.p.m. In recommending that the limit be somewhat higher than was suggested by the Society of Public Analysts and Other Analytical Chemists, the Council stated that in their view a limit of 300 p.p.m. would still be safe having regard to the proportion of A.C.P. which is used in foods containing it. In amplification of these answers the Council informed us that in their opinion it is essential that a limit be set for the amount of fluorine permissible in any material used in food production and suggested that the safest procedure would be to prohibit the use of A.C.P. made from rock phosphate for food purposes. The view was expressed that since the effects of fluorine are cumulative, absorption from the alimentary canal could only be proved or disproved by determining the urinary excretion of fluorine during administration over a period. The argument that the absence of mottling of teeth showed that absorption does not occur was criticised on various grounds. In addition, it was suggested that Roholm's monograph on fluorine poisoning, the recent work of Ockerse in South Africa and Shortt in India, and reports from industries using fluorine compounds, all tended to show that fluorine was a potentially toxic contaminant. In view of the possible effect such an Order would have on certain manufacturers we felt it desirable to acquaint ourselves more fully with the grounds underlying the Council's recommendation, and Dr. Margaret Murray, who had advised the Council on the matter, kindly attended a meeting of the Committee to provide further information. Dr. Murray suggested that it was not justifiable to base any opinion on a short term experiment, since, for example, in the parts of India where fluorosis is endemic, the effects may not become evident for 25 to 30 years. She considered that the balance found by Dr. Archer and Mr. Leech in the intake and excretion of fluorine by their patient must have been largely fortuitous because, apart from the difficulty of accurately determining small quantities in the excreta, fluorine is cumulative and the fluorine excreted on one particular day is not necessarily that ingested the previous day. She agreed that small amounts, in drinking water, had a beneficial effect in tending to prevent caries, but was nevertheless of the opinion that this did not justify the ingestion of fluorine in larger quantities, or from other sources. The further evidence provided by Dr. Murray may be summed up by saying that fluorine, if absorbed in small quantities over a sufficient period of time, can produce gross lesions of bone there is abundant evidence from animal experiments and analyses of human bones that fluorine can be cumulatively absorbed and there is radiological evidence that a mild spondylitis occurs in some children living in areas where the drinking water contains fluorine, although it is possible that the affection occurs only in those children whose nutritional state is poor. We record our appreciation of the assistance rendered by the Medical Research Council and by Dr. Murray. In view of the unquestionable harmfulness of large amounts of fluorine, and of the cumulative effect of small doses, we feel that the risk to the public health from the repeated ingestion of small amounts of fluorine is too serious to be ignored, and that an Order should be made prescribing maximum limits for the contamination.
British Food Journal – Emerald Publishing
Published: Oct 1, 1946