REPORT FOR ANALYTICAL CHEMISTS
THE PRESENT POSITION OF FOOD ADDITIYES IN
GREAT BRITAIN AND THE ANALYTICAL PROBLEMS INVOLVED J. H U B E R T H A M E N C E , M.Sc. Ph.D., F.R.I.C.
VOL. 35, NO. 1, JANUARY 1963
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REPORT
FOR
ANALYTICAL
CHEMISTS
by DR. J. HUBERT HAMENCE
D r . J . H u b e r t H a m e n c e , a Public Analyst and C o n s u l t i n g Chemist, and Director of Dr. Bernard Dyer & Partners of L o n d o n , was born in 1907 a n d graduated with first class honours at London University in 1928. S u b s e q u e n t l y he was awarded t h e degrees of M.Sc. and Ph.D. He c o m m e n c e d his professional career in t h e British Drug Houses a n d s u b s e q u e n t l y joined Dr. Bernard Dyer in private cons u l t i n g practice. He is Public Analyst a n d Official Agricultural Analyst for a n u m b e r of Counties a n d Boroughs. From 1957 to 1959 he was President of t h e Society for Analytical Chemistry and f r o m 1960 to 1962 he was President of t h e Association of Public Analysts. His publications deal mainly with analytical problems connected with agricultural c h e m i s t r y and his present research activities include t h e determinations of pesticide residues.
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As a past president of the Association of Public Analysts of Great Britain, I have been asked to write a short article dealing with the present position in the U. K. as regards food additives with particular reference to legislation, problems involved in their use, and the role that analytical chemistry plays in their control. From time to time scares connected with food additives give rise to headlines in the National Press and the nation is informed, on the very highest authority, that it is being slowly poisoned as the result of the use of chemicals in food. Indeed some writers go so far as to say that our food to-day is "all chemicals." Similarly books are published on the subject from time to time which condemn not only the use of food additives but modern agricultural practices and modern food technology in no uncertain terms. There is nothing new in these condemnations which have been made since Mediaeval times. The fortunate thing, however, to-day is that thanks to scientific developments, in particular to advances in analytical chemistry, we are now in a position to investigate such accusations adequately. As scientists we should perhaps welcome such occasional outbursts since they have the salutory effect, if indeed one is needed, of keeping us on our toes and avoiding a sense of complacency. For some time the possible danger to our foodstuffs from radioactive fall out has distracted attention from additives but more recently the confirmation by chemical analysis that heavy mortalities among our wild bird life in some parts of the country has resulted from the use of dressed seed has once more revived the whole problem of additives.
Food additives are by no means a new problem and oddly enough they were probably more responsible t h a n any other factor for convincing P a r l i a m e n t , in the middle of the nineteenth century, of the need for food legislation. This resulted in 1860 in the passing of the first all-embracing Act known as " a n Act for Preventing the Adulteration of Articles of Food or Drink." I n 1851 D r . Hassell was invited by the Editor of the L a n c e t to examine the purity of the Englishm a n ' s food of t h a t time and he became the first m a n to investigate the adulteration of food scientifically. His results showed t h a t a p a r t from fraudulent adulteration, such as the addition of worthless husks and sand to foodstuffs, it was a common practice a t t h a t time to employ highly poisonous mineral pigments containing arsenic, lead, and mercury for colouring foodstuffs, particularly confectionery. In my view it was the disclosure of the wide spread use of these food additives, employed in ignorance in order to provide customer appeal, which was the major factor in convincing P a r l i a m e n t of the need for legislation. One of the principal provisions of this early Act of P a r l i a m e n t was t h a t it became an offence for any
person to sell an article of food or drink to which it was known an ingredient, or substance, harmful to the health of the persons eating or drinking it, had been mixed. Clearly this enactment covered only one small aspect of food additives but neverthless it was an a t t e m p t to prohibit the use of additives which might be harmful to health. Present Position T o - d a y in the U. K. food additives in general are covered by the provisions of the Food and D r u g s Act 1955. Section (I) of this Act makes it an offence for any person to add any substance to a food or subject the food to any process which would render the food injurious to health. A further provision in this Section is t h a t in determining whether or not an article of food is injurious to health regard should be had not only to the probable effect of t h a t article on the health of a person consuming it but also to the probable accumulative effect of articles of substantially the same composition on the health of a person consuming such articles in ordinary quantities. In this respect, therefore, the English Law is similar to the U. S. L a w prior to the Food Additives Amendment of 1958. I n the U. K. food and drug administration dif-
fers somewhat from the U. S. in t h a t instead of the responsibility for enforcement of the law being vested on the central authority the authority is regionalised and local authorities, counties and boroughs, etc., bear this responsibility. T h e Food and Drugs Act provides for the appointment of Public Analysts, by the local authorities, who are responsible for the analysis of samples of food and drugs submitted to t h e m for examination under the Act. Where additives are concerned, therefore, the English L a w places the burden of responsibility on the shoulders of the public analyst not only to detect the presence of additives in food but also to certify whether or not the presence of such additives renders the food injurious to health. Section (4) of the Act gives the Minister of Agriculture Fisheries & Food power to m a k e Regulations prohibiting or regulating the addition of any specified substance or any substance of a specified class to food intended for sale for h u m a n consumption. Several important Regulations have been m a d e in this respect and these include:— T h e Public H e a l t h Preservatives etc. in Food Regulations. T h e Colouring M a t t e r in Food Regulations. VOL. 35, NO. 1, JANUARY
1963
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S&S
REPORT FOR ANALYTICAL CHEMISTS
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These four Orders cover groups of additives and there are a few other Regulations governing individual additives such as the Mineral Oil in Food Regulations, etc. The general policy on additives in the TJ. K. is that they should be restricted to permitted lists which are prescribed for the different classes or groups in the relevant Regulations. This policy differs considerably from that in the U. S. in that a new additive, however good it may be, must of necessity wait until such time as the relevant Regulations are amended or revised before it may be used in the prepa ration of foodstuffs. There is no need to point out that without Regulations, such as those referred to above, the First Section of the Act would be almost unworkable and in a relatively short time would lead to chaotic conditions. At the turn of the century there was a fair measure of agreement as to the type of additive which was harmful. This was largely due to two facts: — (1) additives considered to be harmful in those days were mainly restricted to the poisonous pigments, and (2) we had still to learn of the possible long term effects such as carcinogenicity of those additives which pro duced no immediate harmful reactions.
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Circle No.138on Readers' Service Card • ANALYTICAL CHEMISTRY
As our knowledge of the possible long term effects of additives in creases clearly the problems become far more complicated and in many
instances the suitability of an ad ditive for human consumption can only be decided by a team of ex perts, each considering the problem from a different scientific point of view. Even under these conditions there is still a wide measure of dis agreement as will be seen from a study of the different food colours which are permitted for use in food stuffs in different countries. A re cent survey has shown that there is only one colour which is univer sally accepted by all nations as be ing suitable for use for colouring foodstuffs. At this stage it is pertinent to consider the general policy with re gard to food additives which pre vails at the present time in the U. K. I would think it fair to say that this policy is excellently summed up in a Report of the Food Stand ards Committee of the Ministry of Agriculture Fisheries and Food on emulsifying and stabilising agents. In this the following statement ap pears:— "Our general view is that it is not in the public interest for chemical substances to be added to food un less there is adequate evidence that their use in food will not affect ad versely the health of the consumer and that a strong case can be made out that their use in food would have advantages economically, technically, or otherwise likely to benefit the consumer." In this connection too it should be pointed out that under Section (4) of the Act it is directed that the responsible Ministers, when consid ering the whole question of ad ditives, should, as far as possible, avoid the use of any substance which is devoid of nutritional value. A review of the Regulations which have been made in this country in respect of additives will show that this policy has, in fact, been generally followed. In mak ing regulations under the Food and Drugs Act the Minister is largely guided by his Food Standards Com mittee which, in turn, appoints a number of Sub-Committees of ex perts to consider specific problems.
The Pharmacological Sub-Committees, on whom falls the responsibility of deciding the suitability of an additive for inclusion in a foodstuff, are sometimes handicapped by lack of reliable toxicological data, particularly in the case of new additives for which little reliable information exists. In this work the Committees are undoubtedly helped by information which is available from the United States where undoubtedly greater facilities are available for obtaining the necessary toxicological information. Just recently in this country a new laboratory has been set up for the purpose of carrying out biological tests on proposed additives. The cost of this new laboratory, which is known as British Industrial Biological Research Association, is borne partly by the Government and partly by Industry. Mention was made in the introduction of this paper that of recent years the possibility of pesticide residues in foodstuffs had given rise to exaggerated reports in the National Press. In my view pesticide residues may fairly be regarded as falling within the scope of this paper since the use of pesticides may clearly be regarded as a process to which the food has been subjected and, therefore, from the point of view of any legal action which might be taken in respect of excessive amounts of pesticide residues Section (I) of the Act is clearly that section under which action could be taken. Such residues could be present in a foodstuff either by excessive applications to the growing crop or by the use of an excessive amount of pesticide in the final stored products. In the U. S. it is the statutory duty of the authorities to lay down rigid limits for residues of all pesticides used in agriculture which represent the maximum residue which should be present when the pesticide is used in the correct manner. In the U. K. the Government is not bound by statute in this man-
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REPORT FOR A N A L Y T I C A L CHEMISTS
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ANALYTICAL CHEMISTRY
As in the U. S. the Committee, in considering residue figures, always allows a very large margin of safety and also takes into consideration any metabolic products which m a y be produced within the crop. If the Committee gives approval for the use of a chemical, then recommendations for use are given by the Committee which specify the dilution and rate which the pesticide is to be applied, and also to the crops to which it is applicable. Recommendations are also made as to whether protective clothing, etc., should be worn b y agricultural
workers while using the pesticide. Two further sections of the Food and Drugs Act assist the responsible authorities in the control of additives. Section (5) gives the M i n istry power to obtain information from Manufacturers concerning the n a t u r e of any chemical additive which they use in the preparation of their food products. Finally Section (7) of the Act gives the Ministry power to m a k e regulations governing the labelling of foodstuffs, in particular in respect of details of their composition. T h e Labelling of Food Order requires a complete disclosure of all ingredients used in the preparation of foodstuffs with certain exceptions, which exceptions unfortunately include some of the more common articles of diet such as bread, etc. T h u s theoretically at any rate, with the exception of certain of the more staple articles of diet, the presence of additives and their n a t u r e should be disclosed on the label. One weakness exists, however, in t h a t in some instances they m a y be covered b y a generic term such as colour or flavour. Accidental contamination of a possible harmful nature, such as m a y be picked up during food process—e.g., contamination with traces of heavy metals of the nature of lead and copper and arsenical contamination—scarcely fall within the category of additives b u t nevertheless such possible contaminants of foodstuffs are covered by regulations which specify the maximum permissible quantities for different foodstuffs. To a certain extent, packaging and contamination which m a y be acquired through use of unsuitable wrapping materials falls within a similar category. The Plastic Federation of the U. K. has long realized the possible danger to foodstuffs due to the use of unsatisfactory plastic wrapping and packaging materials and some six years ago established a Toxicity Sub Committee to deal with this aspect of their work. I n general it m a y be
said t h a t t w o possible sources of trouble m a y arise from t h e use of unsatisfactory wrapping mate rials:— (1) a n additive which is pro hibited b y one, or more, of the Regulations m a y be in troduced into t h e foodstuffs; as examples we m a y quote the introduction of formalde hyde which is a prohibited preservative a n d , secondly, the introduction of antioxi dants which are n o t only r e stricted t o certain compounds but also to certain foodstuffs, and
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(2) t h e introduction of a sub stance which, even if present in only relatively small amounts, would be regarded as being objectionable. As in the U. S., tests for t h e suit ability of their use in food p a c k a g ing are usually based on extraction with different solvents which m a y either t a k e t h e form of water with, and without, the addition of mild acids a n d alkalies or ethyl alcohol and finally oils or fats. Quite clearly t h e analytical chemist is the k e y to t h e enforce m e n t of all Regulations relating t o additives. T h e detection of t h e early additives was a relatively sim ple m a t t e r since these were mainly poisonous mineral pigments a n d all t h a t was required was t h e detection of milligram quantities. To-day the whole position has changed a n d where milligram quantities were concerned one hundred years ago it is now a question of microgram quantities a n d even less. T h e first impetus in t h e detection of microgram quantities came with the unfortunate outbreak of arseni cal poisoning in the N o r t h of E n g land in 1903 in which m a n y deaths occurred through t h e consumption of beer contaminated with arsenic. This led t o t h e development of highly sensitive modifications of t h e M a r s h Test which were slowly r e placed by t h e even more sensitive Gutzeit Test.
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REPORT FOR ANALYTICAL CHEMISTS
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ANALYTICAL
CHEMISTRY
T h e next advance to be made was in the field of the detection of microgram quantities of lead, copper, and zinc and the development of sensitive methods for these metals led to a complete reappraisal of our ideas of these contaminants. It also led to revolutionary techniques for the detection of trace metals involving the use of organic complexes and their separation from solution by the use of organic solvents. The introduction of the Preservative Regulations saw yet another stage in the chain of development. H i t h e r t o the chemist concerned with the detection of additives had dealt with arsenic and metals. Now he became concerned with the detection of traces of organic compounds and their separation from a mass of interfering organic material. When the P r e servative Regulations were first made the problem was regarded with some horror but very soon the ingenuity of the chemist t r i umphed and it became a simple m a t t e r to estimate the proportion of benzoic acid in p a r t s per million in the common foodstuffs. The introduction of the spectrophotometer has m a d e the problem even simpler. From then onwards the introduction of physical methods has solved m a n y of the problems in connection with the detection of additives and has made estimation and identification possible where years ago the problem would have appeared insoluble. P a p e r chromatography provided the answer to the separation and detection of the different colouring m a t t e r s which are permitted in foodstuffs by the Colouring M a t t e r in Foodstuffs Regulations and in 1959 the Association of Public Analysts published a monograph outlining a scheme for this purpose which was based entirely on paper chromatography with a final check of the absorption spectra where necessary. P a p e r chromatography has again proved invaluable for the detection and estimation of anti oxidants.
So far in the U. K., therefore, analytical chemistry has kept u p with the demands m a d e upon it by the various Regulations relating to additives. At the present time, however, food chemists arc engaged in a problem which still remains only p a r t l y resolved, namely t h a t of the separation and detection of the various emulsifying and stabilising agents. The new Emulsifying and Stabilising Food Regulations come into operation later this year and much work still remains to be done on the separation and identification of these relatively inert materials which yield few really characteristic reactions. We now come to pesticide residues. Although a t the present time in the TJ. K. we have no legal enactments which specifically limit the amounts of such residues which m a y be present in foodstuffs, nevertheless their presence in excess would be largely controlled by the general provisions of the Food and D r u g s Act and therefore the determination of pesticide residues is a m a t t e r which is uppermost in the minds of m a n y public analysts and food chemists. There are in existence t o - d a y a large number of methods for the determination of m a n y individual pesticides and the problem would be a simple one if the a n a l y s t knew the previous history of the foodstuff from the point of view of pesticide usage. I t would, however, be quite impossible to examine all foodstuffs for all likely pesticides employing an individual test for each one and therefore we are actively engaged in exploring the possibility of using biological sorting tests for deciding which samples w a r r a n t a detailed examination. Unfortunately we have y e t to find an organism which will respond to all known pesticides and therefore reliable sorting tests m u s t be based on the use of two or more organisms. At the present time the use of drosophila melanogester (the fruit fly) and daphnia obtusa (the water flea) seems to be
the most useful combination of tests for this purpose. Chromatography, in its various forms, has proved an almost indis pensable tool in pesticide work. For many years column chroma tography has proved to be almost the only method of separating im purities in the final clean-up proc ess prior to the final assessment. Column chromatography was also used very successfully for separat ing macro quantities of different chlorinated hydrocarbon pesticides. Paper chromatography has proved invaluable for the separation and estimation of traces of chlori nated hydrocarbon and phosphorus pesticides. A major advance was made in this work when gas liquid chroma tography, using electron capture ionisation detection, was introduced for the estimation of chlorinated hydrocarbon pesticides and it is to be hoped that, by suitable modifica tions of this, it will become appli cable to the detection and determi nation of the phosphorus com pounds. One of the great advan tages of this new technique is that considerably less clean-up is re quired than for other forms of esti mation. Final mention may be made of vitamins which are now frequently added to foodstuffs to reinforce the natural vitamins in a number of foodstuffs. Under our Labelling of Food Order where claims for the presence of vitamins are made, the manufacturer must declare on the label the amount of such additions per ounce of the foodstuff. Modern analytical chemistry, employing the newer physical methods, now en ables the analyst to determine all additives of this nature, vitamin D being the only exception. The successful control of addi tives clearly depends on the skill of the analytical chemist and he, in turn, must rely on modern instru mentation and physical methods for the detection and determination of the ever-increasing variety of materials which are now used as food additives. END •
MULTIPLE REFLECTION ... a technique which greatly extends the usefulness of attenuated total reflectance
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The use of this technique greatly broadens the applications of Attenuated Total Reflectance spectroscopy. Nor mally, ATR spectra are slightly weaker in appearance than those obtained by transmission since the ATR 'pathlength' is only a few microns. But by taking several reflections of the sample, using the Multiple Reflection Accessory, re gions of particular interest or the entire spectrum can be multiplied by as much as a factor of four. If you are interested in this acces sory or would like to know more about A t t e n u a t e d Total Reflectance tech niques, write or visit CIC.
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3 5 , N O . 1 , JANUARY
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1963
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