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The use of preservatives in food
~,-b,r, ~9~J The Use of Preservatives in Food
101
THE USE OF PRESERVATIVES IN FOOD.* BY W. ARNOLD EVANS, M.D. (LOND.), B.SC. (VICT.), Medical Officer of I~Iealth, Bradford. AT the outset it is useful to ask, Why should preservatives of any kind be used at all ? I shall not refer in these few remarks to such wellknown methods of preserving food as sterilization, pasteurization, smoldng, or refrigeration, but confine myself simply to the compounds of boric acid, salicylates, formic aldehyde, sulphurous acid, and the sulphites, etc., in fact, to those substances usually known as chemical preservatives. Speaking in a general sense, the object of adding preservatives ~o food is to prevent what is commonly described as decomposition or putrefaction, and so to keep foods for a greater time in an apparently fresh condition. That the appearance of freshness is accomplished by addition of so-called preservatives is beyond question, and firnfly established by evidence given before the Departmental Committee to enquire into the use of preservative and colouring matters in the preservation and colouring of foods. ]?or instance, the analyst to the Aylesbury Dairy Company showed that milk at a temperature of 60° F. without any preservative would turn sour in fifty hours, whilst with the addition of 4"4 grains of borax per pint it would be sweet at the end of over eighty hours, and that if the boric preservative were increased to double this amount it would not become sour for 110 hours. Although, as pointed out by Thresh and Porter, chemical preservatives may inhibit the action of enzymes and bacteria, and so prevent such phenomena as the souring of milk, they may be, and are, quite powerless to prevent the growth of many micro-organisms, pathogenic or otherwise. Their use may therefore lead to a false sense of security, by making the ordinary" changes of decomposition detected by the sense of taste or smell, and causing the consumer to believe that he is swallowing fresh food, but one which may contain large quantities of micro-organisms, such as the Bacillus enteritidis and others known to be concerned in the production of zymotic diarrhoea. Prof. Delepine has shown that B. typhosus, enteritidis, an4 colt communis will multiply at a temperature of 65° F. in the presence of 149 grains per gallon of a mixture of borax and boric acid. So that, * Read before the Yorksbire Branch of the Incorporated Society of Medical Officers of Health at Bradford, October 19th, 1906. 11
160,
The U s e of P r e s e r v a t i v e s in F o o d
[r,,bno ,,o~lth
owing to the absence of curdling, a consumer might take a quantity of really stale milk in which pathogenic organisms may have been multiplying for thirty or forty hours, in which if the ordinary signs of acidity and curdling had been present he would have rejected as unfit for consumption. The explanation of the fact that boric preservative delays the production of acidity and curdling in milk appears to be that the activity of the lactic and bacillus which acts on the carbohydrates is affected earlier, or is more sensitive to the presence of boric acid than are those pathogenic bacilli of the typhosus type, which multiply more rapidly in the presence of proteid matter. But apart from the fact that chemical preservatives inhibit decomposition, and so allow food purveyors to sell as fresh something that is really not fresh, the ingestion of the preservative itself is attended with deleterious consequences. Some observers, viz., Annett, Rideal, Foulerton, and others, have experimented on animals, using rabbits, kittens, dogs, and pigs for the purpose, and all have found that the administration of repeated doses of boric acid and borax have produced temporary disturbances of the function of the digestive organs, as. evidenced by toss of bodily weight, and in the case of one set of kittens by emaciation. The evidence given by witnesses who attended before the Departmental Committee prove that a similar effect is produced in man. Some witnesses, e.g., Dr. Wild and Dr. Tubb-Thomas, testify as to the effect upon themselves of the ingestion of boric acid (Thresh and Porter) ; the former administered to himself doses of 15 to 20 grains of boric acid a day, with the result that after a few days he experienced discomfort after food, loss of appetite, flushing of the skin, and general malaise. After three or four weeks there was a severe eruption spreading from the palms of the hands to the body, face, and head. The hair fell of[, and nearly the whole skin was reddened and covered with scales. This condition was ameliorated as soon as the drug was discontinued; subsequently the treatment was adopted again, with similar results. Dr. Thomas gave himself boric acid to the extent of 15 grains a day, with the result that vomit~ng, diarrhoea, headache, and almost complete suppression of urine took place. Mr. Reginald Harrison also, in a letter to the Lancet of March 21st, 1903, describes the disturbing effect of boric acid on the digestion of heatthy persons and invalids when taken internally, and states it is the only thing he knows of capable of giving him indigestion at almost a moment's notice. The most complete research, however, on the action of boric acid on man is that of Dr. Wiley, chief of the Bureau of Chermstry of the United States Board of Agriculture. He
neoember,
1906]
The Use of P r e s e r v a t i v e s in F o o d
163
experimented on twelve men~ and his operations extended over 196 days, during which he took careful observations and adopted means to ensure that all the men lived under exactly similar conditions; he sums up his conclusion as follows : " It appears, therefore, that both boric acid and borax, when continuously administered in small doses for a long period, or when given in larger quantities for a short period, create disturbance of appetite, of digestion, and health." It seems to me not improbable that many cases of indigestion, loss of appetite, and various forms of dyspepsia the cause of which may not be apparent~ may be accounted for by the continued administration of preservatives taken with food. It should be borne in mind that only three years ago there was an unusual incidence, chiefly in the North of England, of a malady characterized by skin eruption and peripheral neuritis, which proved on investigation to be arsenical poisoning. Now that the attengion of the medical profession has been markedly called to the extent of the use uf chemical preservatives in Iood, perhaps the cause of some apparently inexplicable cases of gastric and intestinal disturbances will bebrought to light. "Rideal and Foulerton found that milk curdled on being heated to 100° C. as soon as the acidity expressed as lactic acid reached the proportion of 0"25 per cent, and they took this figure as the point at which the milk ought to be considered sour and unfit for sale. They found that by adding 35 grains of a mixture of boric acid and borax to a gallon of milk (-~to 0"05 per cent), the souring point was de~ayed, and the milk so treated would remain uncurdled for more than 24 hours at 75~ F., whilst without such addition souring took-place within that period. Apparently this is the smallest quantity which can be relied upon to keep lnilk sweet for 24 hours in hot weather." My experience is that b~ric acid is only contained in milk produced in cowsheds known to be filthy. The prevalence of the practice of using, preservatives for food is indicated by the ~evidence given by analysts before the Departmental Committee. Dr Hill, of Birmingham, found that in milk, out of 1,537 samples, 135, or 8"9 per cent, contained some kind of preservative, whilst Mr. Williams, of Liverpool, discovered only 2"1 per cent preservatized milks out of a total of 862 examined; and in Cardiff, 8"5 per cent of the samples of milk taken in 1898 were reported to contain boric acid. Of the samples of milk examined in Bradford during the past year, only some three or four were reported by the anMyst to contain boric acid or borax. However, on two occasions milk purveyors have been
164
The
U s e of P r e s e r v a t i v e s in F o o d
[r~bhoH~am
found to introduce a varying amount of borax into the empty milk cans, which are filled from the churns of milk received by train at the railway stations. In butter, the evidence before the same Committee showed that in Cardiff 44"5 per cent of the samples contained some preservative ; and the experiment of the Government Laboratory showed that over 50 per cent of the samples obtained by them from home and abroad were preserved with boric acid. The question remaining for consideration is, whether or not the Sale of Food and Drugs Act o.f 1875, as amended by subsequent Acts, is sufficient to cope with the ever-increasing use of food preservatives. In the description of offences in Sections 3 and 6 in the Act of 1875 there is no mention of the word ~' preservative." The words used being "mix, colour, stain, or powder" ; and legal proceedings that have been taken under these sections, with the object of preventing the addition of preservatives, have met with varying results, but it appears to me that generally, when chemical preservatives of any kind, beyond an infinitesimal amount, are discovered in liquid foods action under these sections should be taken. In reference to milk, the recommendation of the Local Government~ Board in their circular of July of this year appears to be a good one. The Board recommend that local authorities should notify milk traders by circular, or otherwise, that action will be taken in instances where preservatives are reported in milk, and afterwards treat such practices as actionable. The treatment of solids, such as hams and bacon, by boric acid is not apparently so serious as the addition of preservatives to milk, for the reason that they are applied externally, and probably t~ a large extent removed before consumption. In some other solids, however, the preservative may be intimately mixed, in such cases, for instance, as potted shrimps, potted meat, etc., and should preservatives in these be found above the limit allowed by the Departmental Committee, action should certainly be taken. Recently penalties to the extent of over £9 were recovered in the Bradford City Court from shrimp dealers, whose shrimps were certified to contain 88 and 108 grains per pound.* It may, perhaps, not be a waste of time if I read over the recommendations of the Departmental Comnfittee :-(a). That the use of formaldehyde or formalin, or preparations thereof, in foods or drinks, be absolutely prohibited, and that salicylic See repor~ of case, PUBLICHEALTH,November, 1906, p. 104.
D~,m~,r,--0Sl The Use of Preservatives in Food
165
acid be not used in a greater proportion than 1 gr. per pint in liquid food and 1 gr. per pound in solid food. Its presence in all cases to be declared. (b). That the use of any preservative or colouring matter whatever in milk offered for sale in the United Kingdom be constituted an offence under the Sale of Food and Drugs Act. (c). That the only preservative which it shall be lawful to use in cream be boric acid or mixtures of boric acid and borax, and in amount not exceeding 6"25 per cent expressed as boric acid. The amount of such preservative to be notified by a label upon the vessel. (d). That the only preservative permitted to be used in butter and margarine be boric acid or mixtures of boric acid and borax, to be used in proportions not exceeding 0"5 per cent expressed as boric acid. (e). T h a t in the case of all dietetic preparations intended for the use of invalids or infants, chemical preservatives of all kinds be prohibited. (/). That the use of copper salts in the so-called greening of preserved Goods be prohibited. (g). That means be provided, either by the establishment of a separate Court of Reference, or b y the imposition of more direct obhgation on the Local Government Board, to exercise supervision over the use of preservatives and colouring matters in food, and to prepare schedules of such as may be considered inimical to the public health. DISCUSSION. DR. SCATTERTY, while deprecating the introduction of preservatives of any kind in milk, disputed the suggestion that boric acid was injurious to health. He had given, he said, boric acid in considerable doses in cases of cystitis with beneficial effects. DR. SPOTTISWOODECAMERON said that that argument could not be considered valid. In certain cases amputation of a leg was highly beneficial to a man, but to a healthy man the amputation of a leg was by no means harmless, and was not to be recommended. FRUIT GROWING ON SEWAGE FARMS.--Mr. H. H. Marks having asked the representative of the President of the Board of Agriculture in the House of Commons whether any action had been taken, or was contemplated, with reference to the recommendation of the departmental committee on the fruit industry that an enquiry should be instituted in to the alleged practice of growing fruit on sewage farms, and the effect of such a practice on the pubhc health, Sir E. Strachey replied : We have been in communication with the Local Government Board on this subject, and we are informed that no instance of disease attributed to fruit grown on sewage farms is known in the Medical Department of the Board. The information in the possession of the Board indicates that fruit is seldom grown on sewage farms in this country, and there is no confirmation of the suggestion that injury to health is caused by fruit so grown.
101
THE USE OF PRESERVATIVES IN FOOD.* BY W. ARNOLD EVANS, M.D. (LOND.), B.SC. (VICT.), Medical Officer of I~Iealth, Bradford. AT the outset it is useful to ask, Why should preservatives of any kind be used at all ? I shall not refer in these few remarks to such wellknown methods of preserving food as sterilization, pasteurization, smoldng, or refrigeration, but confine myself simply to the compounds of boric acid, salicylates, formic aldehyde, sulphurous acid, and the sulphites, etc., in fact, to those substances usually known as chemical preservatives. Speaking in a general sense, the object of adding preservatives ~o food is to prevent what is commonly described as decomposition or putrefaction, and so to keep foods for a greater time in an apparently fresh condition. That the appearance of freshness is accomplished by addition of so-called preservatives is beyond question, and firnfly established by evidence given before the Departmental Committee to enquire into the use of preservative and colouring matters in the preservation and colouring of foods. ]?or instance, the analyst to the Aylesbury Dairy Company showed that milk at a temperature of 60° F. without any preservative would turn sour in fifty hours, whilst with the addition of 4"4 grains of borax per pint it would be sweet at the end of over eighty hours, and that if the boric preservative were increased to double this amount it would not become sour for 110 hours. Although, as pointed out by Thresh and Porter, chemical preservatives may inhibit the action of enzymes and bacteria, and so prevent such phenomena as the souring of milk, they may be, and are, quite powerless to prevent the growth of many micro-organisms, pathogenic or otherwise. Their use may therefore lead to a false sense of security, by making the ordinary" changes of decomposition detected by the sense of taste or smell, and causing the consumer to believe that he is swallowing fresh food, but one which may contain large quantities of micro-organisms, such as the Bacillus enteritidis and others known to be concerned in the production of zymotic diarrhoea. Prof. Delepine has shown that B. typhosus, enteritidis, an4 colt communis will multiply at a temperature of 65° F. in the presence of 149 grains per gallon of a mixture of borax and boric acid. So that, * Read before the Yorksbire Branch of the Incorporated Society of Medical Officers of Health at Bradford, October 19th, 1906. 11
160,
The U s e of P r e s e r v a t i v e s in F o o d
[r,,bno ,,o~lth
owing to the absence of curdling, a consumer might take a quantity of really stale milk in which pathogenic organisms may have been multiplying for thirty or forty hours, in which if the ordinary signs of acidity and curdling had been present he would have rejected as unfit for consumption. The explanation of the fact that boric preservative delays the production of acidity and curdling in milk appears to be that the activity of the lactic and bacillus which acts on the carbohydrates is affected earlier, or is more sensitive to the presence of boric acid than are those pathogenic bacilli of the typhosus type, which multiply more rapidly in the presence of proteid matter. But apart from the fact that chemical preservatives inhibit decomposition, and so allow food purveyors to sell as fresh something that is really not fresh, the ingestion of the preservative itself is attended with deleterious consequences. Some observers, viz., Annett, Rideal, Foulerton, and others, have experimented on animals, using rabbits, kittens, dogs, and pigs for the purpose, and all have found that the administration of repeated doses of boric acid and borax have produced temporary disturbances of the function of the digestive organs, as. evidenced by toss of bodily weight, and in the case of one set of kittens by emaciation. The evidence given by witnesses who attended before the Departmental Committee prove that a similar effect is produced in man. Some witnesses, e.g., Dr. Wild and Dr. Tubb-Thomas, testify as to the effect upon themselves of the ingestion of boric acid (Thresh and Porter) ; the former administered to himself doses of 15 to 20 grains of boric acid a day, with the result that after a few days he experienced discomfort after food, loss of appetite, flushing of the skin, and general malaise. After three or four weeks there was a severe eruption spreading from the palms of the hands to the body, face, and head. The hair fell of[, and nearly the whole skin was reddened and covered with scales. This condition was ameliorated as soon as the drug was discontinued; subsequently the treatment was adopted again, with similar results. Dr. Thomas gave himself boric acid to the extent of 15 grains a day, with the result that vomit~ng, diarrhoea, headache, and almost complete suppression of urine took place. Mr. Reginald Harrison also, in a letter to the Lancet of March 21st, 1903, describes the disturbing effect of boric acid on the digestion of heatthy persons and invalids when taken internally, and states it is the only thing he knows of capable of giving him indigestion at almost a moment's notice. The most complete research, however, on the action of boric acid on man is that of Dr. Wiley, chief of the Bureau of Chermstry of the United States Board of Agriculture. He
neoember,
1906]
The Use of P r e s e r v a t i v e s in F o o d
163
experimented on twelve men~ and his operations extended over 196 days, during which he took careful observations and adopted means to ensure that all the men lived under exactly similar conditions; he sums up his conclusion as follows : " It appears, therefore, that both boric acid and borax, when continuously administered in small doses for a long period, or when given in larger quantities for a short period, create disturbance of appetite, of digestion, and health." It seems to me not improbable that many cases of indigestion, loss of appetite, and various forms of dyspepsia the cause of which may not be apparent~ may be accounted for by the continued administration of preservatives taken with food. It should be borne in mind that only three years ago there was an unusual incidence, chiefly in the North of England, of a malady characterized by skin eruption and peripheral neuritis, which proved on investigation to be arsenical poisoning. Now that the attengion of the medical profession has been markedly called to the extent of the use uf chemical preservatives in Iood, perhaps the cause of some apparently inexplicable cases of gastric and intestinal disturbances will bebrought to light. "Rideal and Foulerton found that milk curdled on being heated to 100° C. as soon as the acidity expressed as lactic acid reached the proportion of 0"25 per cent, and they took this figure as the point at which the milk ought to be considered sour and unfit for sale. They found that by adding 35 grains of a mixture of boric acid and borax to a gallon of milk (-~to 0"05 per cent), the souring point was de~ayed, and the milk so treated would remain uncurdled for more than 24 hours at 75~ F., whilst without such addition souring took-place within that period. Apparently this is the smallest quantity which can be relied upon to keep lnilk sweet for 24 hours in hot weather." My experience is that b~ric acid is only contained in milk produced in cowsheds known to be filthy. The prevalence of the practice of using, preservatives for food is indicated by the ~evidence given by analysts before the Departmental Committee. Dr Hill, of Birmingham, found that in milk, out of 1,537 samples, 135, or 8"9 per cent, contained some kind of preservative, whilst Mr. Williams, of Liverpool, discovered only 2"1 per cent preservatized milks out of a total of 862 examined; and in Cardiff, 8"5 per cent of the samples of milk taken in 1898 were reported to contain boric acid. Of the samples of milk examined in Bradford during the past year, only some three or four were reported by the anMyst to contain boric acid or borax. However, on two occasions milk purveyors have been
164
The
U s e of P r e s e r v a t i v e s in F o o d
[r~bhoH~am
found to introduce a varying amount of borax into the empty milk cans, which are filled from the churns of milk received by train at the railway stations. In butter, the evidence before the same Committee showed that in Cardiff 44"5 per cent of the samples contained some preservative ; and the experiment of the Government Laboratory showed that over 50 per cent of the samples obtained by them from home and abroad were preserved with boric acid. The question remaining for consideration is, whether or not the Sale of Food and Drugs Act o.f 1875, as amended by subsequent Acts, is sufficient to cope with the ever-increasing use of food preservatives. In the description of offences in Sections 3 and 6 in the Act of 1875 there is no mention of the word ~' preservative." The words used being "mix, colour, stain, or powder" ; and legal proceedings that have been taken under these sections, with the object of preventing the addition of preservatives, have met with varying results, but it appears to me that generally, when chemical preservatives of any kind, beyond an infinitesimal amount, are discovered in liquid foods action under these sections should be taken. In reference to milk, the recommendation of the Local Government~ Board in their circular of July of this year appears to be a good one. The Board recommend that local authorities should notify milk traders by circular, or otherwise, that action will be taken in instances where preservatives are reported in milk, and afterwards treat such practices as actionable. The treatment of solids, such as hams and bacon, by boric acid is not apparently so serious as the addition of preservatives to milk, for the reason that they are applied externally, and probably t~ a large extent removed before consumption. In some other solids, however, the preservative may be intimately mixed, in such cases, for instance, as potted shrimps, potted meat, etc., and should preservatives in these be found above the limit allowed by the Departmental Committee, action should certainly be taken. Recently penalties to the extent of over £9 were recovered in the Bradford City Court from shrimp dealers, whose shrimps were certified to contain 88 and 108 grains per pound.* It may, perhaps, not be a waste of time if I read over the recommendations of the Departmental Comnfittee :-(a). That the use of formaldehyde or formalin, or preparations thereof, in foods or drinks, be absolutely prohibited, and that salicylic See repor~ of case, PUBLICHEALTH,November, 1906, p. 104.
D~,m~,r,--0Sl The Use of Preservatives in Food
165
acid be not used in a greater proportion than 1 gr. per pint in liquid food and 1 gr. per pound in solid food. Its presence in all cases to be declared. (b). That the use of any preservative or colouring matter whatever in milk offered for sale in the United Kingdom be constituted an offence under the Sale of Food and Drugs Act. (c). That the only preservative which it shall be lawful to use in cream be boric acid or mixtures of boric acid and borax, and in amount not exceeding 6"25 per cent expressed as boric acid. The amount of such preservative to be notified by a label upon the vessel. (d). That the only preservative permitted to be used in butter and margarine be boric acid or mixtures of boric acid and borax, to be used in proportions not exceeding 0"5 per cent expressed as boric acid. (e). T h a t in the case of all dietetic preparations intended for the use of invalids or infants, chemical preservatives of all kinds be prohibited. (/). That the use of copper salts in the so-called greening of preserved Goods be prohibited. (g). That means be provided, either by the establishment of a separate Court of Reference, or b y the imposition of more direct obhgation on the Local Government Board, to exercise supervision over the use of preservatives and colouring matters in food, and to prepare schedules of such as may be considered inimical to the public health. DISCUSSION. DR. SCATTERTY, while deprecating the introduction of preservatives of any kind in milk, disputed the suggestion that boric acid was injurious to health. He had given, he said, boric acid in considerable doses in cases of cystitis with beneficial effects. DR. SPOTTISWOODECAMERON said that that argument could not be considered valid. In certain cases amputation of a leg was highly beneficial to a man, but to a healthy man the amputation of a leg was by no means harmless, and was not to be recommended. FRUIT GROWING ON SEWAGE FARMS.--Mr. H. H. Marks having asked the representative of the President of the Board of Agriculture in the House of Commons whether any action had been taken, or was contemplated, with reference to the recommendation of the departmental committee on the fruit industry that an enquiry should be instituted in to the alleged practice of growing fruit on sewage farms, and the effect of such a practice on the pubhc health, Sir E. Strachey replied : We have been in communication with the Local Government Board on this subject, and we are informed that no instance of disease attributed to fruit grown on sewage farms is known in the Medical Department of the Board. The information in the possession of the Board indicates that fruit is seldom grown on sewage farms in this country, and there is no confirmation of the suggestion that injury to health is caused by fruit so grown.