Foodstuffs and gas contamination

PUBLIC HEALTH first importance are the particular occupational hazards in a given industry, and without a knowledge of these the medical man's general supervision of the health of the workers will lack a solid basis. At present the medical examination of new employees under 16 and of workers in certain special processes is compulsory, but the committee's opinion is that m~dical examination of other new entrants should be compulsory. Such a measure would seem to be of the highest importance, especially if adequate methods of examination were available--as, for example, miniature radiography. This would afford an excellent opportunity of detecting disease at an early stage and those variations from the physical and mental norm which can be corrected by suitable regime and treatment. If such an examination were accompanied by intelligence and vocational tests employees could be drafted into occupations suited to their individual qualities. In this country the industrial field is so wide that it offers unrivalled opportunities for mass observation Of the various factors making for health and disease and for the collection of statistical records. One problem calls for solution, and that is the higher sickness absence rate in women, which is apparently not wholly to be explained by gynaecological conditions. The increased incidence of tuberculosis among women in industry in the last war, and the foreshadowings of such an increase in this war, are just one indication that women are being subjected to a strain either to which they are not physiologically adapted or which becomes too great when the factory worker at the same time has heavy domestic duties and/or worries. On the matter of appointment, the committee doubts whether it is satisfactory that this should be made by the employer, and suggests that an advisory body under the aegis of a Government Department should be set up to guide employers in making a suitable choice. Obviously medical men of experience and authority should have the biggest say in the choice of medical personnel, and with the establishment of harmonious relations with industry it is probable that industrial managements would hesitate to turn down the strong recommendations of an independent and impartial outside body. It is essential that the industrial medical officer should be given the greatest possible freedom in carrying out his duties and in making his recommendations for the improvement of the health of the workers. The danger that he may be looked upon as being on the side of the management is one that must be constantly guarded against, and in the long run this can be secured only if the industrial medical officer does not feel hampered in the making of recommendations that will prove unpopular to the management. Although he must take into full account the point of view of the management his first concern must always be for the health and safety of the worker, and once the workers know this their full co-operation in preventive and hygienic methods will be secured to the evident advantage of themselves and to the industry in which they work. The report stresses the need for close relations between industrial medical officers and the general practitioner. So also should there be the closest

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DECEMBER relations with the public health department of the district ifi which the--fact0ry is situated. The report states that, though the medical officer of health has the statutory right of entry into all factories and workshops, he is concerned " only with water closets and the provision of fire escapes." " Matters of factory hygiene, ventilation, cleanliness, spacing, temperature, etc., are controlled by the Factory Inspection Department of the Ministry of Labour (formerly of the Home Office). Only a small proportion of the factory inspectors, however, are medical practitioners, in 1940 the proportion being approximately one for every 500,000 workers." This statement is incomplete, as according to the Factories Act a district council can enforce the provisions relating to cleanliness, temperature, ventilation, etc., in any factory in which mechanical power is not used. Ir~ any event the situation is anomalous. Industrial medicine is, after all, essentially a branch of public health in its widest sense. It would indeed seem inadvisable to set up a special and separate industrial medical service under the administration of the Ministry of Labour. For that unification towards which everyone now seems to be striving, industrial medicine should be administered as a part of the public health service under the Ministry of Health. The report of the committee has many wise things to say on medical education and research in the new field with which its report deals. It is pointed out that the Industrial Health Research Board is not able to spend money without the consent of the Medical Research Council, and that the Secretary of this Board is, during the present war, required to devote part of his time to acting as Chief Medical Officer to the Ministry of Supply. A wisely devised research organisation in industry should be able to make valuable contributions to the problems of health and disease in the community at large. The full report will repay the close attention of all those in the public health service.

Foodstuffs and Gas Contamination The information contained in the Ministry of Food's Public Information Leaflet No. 6, Poison Gas and Food in Your Home, was intended as a bare outline of the simple measures to be taken to protect food against poison gas, and contained instructions on what should be done should food be contaminated; this was considerably amplified in the Ministry's memorandum, Food and its Protection Against Poison Gas. In this pamphlet the possible contamination of foodstuffs in the home, in retail shops, and in institutions, and of food stored in bulk in warehouses and docks is considered. Full information is given about the protection afforded by different materials holding or covering foodstuffs, and the effects of poison gases on some foodstuffs. The administrative arrangements for dealing with food contaminated by poison gases are set out in the Ministry of Food's Memoranda M.F.G. Nos. 1, 3 and 4. It is with the help of the information in these documents that local authorities have for some time past, each in the light of its own peculiar problems, been formulating their proposals and setting up the necessary organisation,

1941 The problems arising are discussed in the July issue of the journal of the Royal Sanitary Institute. Dr. Page, of the Imperial College of Science and Tech,mlogy, deals more particularly with the damage to foodstuffs, amplifying in certain respects the information contained in the Ministry of Food's pamphlet. He points out that the damage will depend on the chemical and physical properties of the foodstuffs themselves and of the chemical used, and on the degree of exposure of the foodstuffs to, the chemical. Foods may absorb substances by solution in the water or fat that they contain, or by adsorption on their solid surfaces. Either process may be followed by some degree of breakdown of the chemical. Absorbed substances subjected to the hydrolysing action of water are in the main converted into comparatively inniscuous products, though lewisite will still be poisonous even if deprived of its vesicant properties. Hydrolysis being so much slower a process than solution, exposed watery foods or liquids may remain contaminated for a long period. Solution in fats is seldom followed by any action comparable to the hydrolysis effected by water, so that the surface of a fatty food once contaminated is usually permanently unfit for human consumption. While the chemicals used in chemical warfare are nearly all liquid or solid at ordinary temperatures, liquids are sufficiently volatile for a proportion to exist as gas. The degree of volatility not only affects the extent of penetration of foodstuffs on exposure, but also determines the success of decontamination by airing. In general it may be said that the more volatile the liquid the more rapidly it will diffuse into the air spaces in granular foods, and the more rapidly it can be subsequently diffused out again by airing. Most of the vapour, however, even of the most volatile of the war chemicals, will probably be absorbed by the outer layers of the food. The most serious degree of contamination will arise from contact of the foodstuffs with the liquid chemicals in the form of splashes or of spray. As this will be limited in general to the less volatile liquids the contamination produced is initially heavy and is difficult to remove by airing. These considerations emphasise the importance of studying the ways of protecting food against exposure to contamination by liquid, and to a lesser extent by vapour. Dr. Page deals with the principles to be considered both in stacking and in the seIection of containers for food, and, discussing some of the problems arising in the sampling of contaminated foodstuffs, stresses the importance of sampling being carried out carefully and systematically. He points to the necessity of obtaining samples not only from the surface and from the interior of packages but also from packages in the interior of a pile. In the tests carried out in the laboratory the most important is that for the presence of arsenic, the two next in importance being those for mustard and lewisite. Most methods make use of the removal of a sufficient quantity of the substance as a gas in a stream of purified air, from which the substance is recovered in solution and identified by specific tests. Because of the low volatility of some of the gases and the degree to which they are held by most foods, these tests, even where they may be

PUBLIC HEALTH successful qualitatively, may be unreliable quantitatively. The paper in the same issue of the Institute Journal by Mr. Roland Woods, the gas contamination officer of the County Borough of Sunderland, raises points of real importance to the administrative officer responsible for the operation of the scheme, and includes informative detailed instructions by the Borough Public Analyst on the sampling for analysis of foodstuffs contaminated by poison gas.

Safe Milk As Dr. E. W. McHenry in a symposium on milk* points out, recent food surveys in Great Britain, the U.S.A., and Canada have shown that the main dietetic deficiencies are in calcium, iron, and the vitamin-B group. Milk, as everyone knows, is a valuable protective food, and a most convenient source of calcium-a common dietary deficiency in Canada. The Canadian Council on Nutrition has recommended that an adult should have at least half a pint of milk daily, and that children should have according to their age from one and a quarter pints to one quart daily. Dr. W. C. Hopper, however, shows that the average Canadian consumption per head is 0.55 to 0.75 pint per day. In four cities the average was 0"70 pint and in three villages 0.63 pint, whereas in 828 farm households the figure was 1.87 pints. But on farms the amount of whole milk consumed varies greatly. In some cases the amount of buttermilk drunk averaged 0.27 pint per day. As was to be expected, low-income families took less milk than families with high incomes. Only 28 per cent. of the adults in 3,207 families drank milk, and over 20 per cent. of children in the households visited drank no milk. In a more detailed study relating to the Vancouver area, J. S. Kitching found that 46 per cent. of the families were drinking less milk than the minimum suggested by the Canadian Council of Nutrition. Pasteurised milk only was drunk by 74 per cent. of the families, raw milk by 20 per cent., and 6 per cent. had both. Consumption of milk is one thing ; consumption of safe milk is another. As a step towards securing safe milk, A. R. B. Richmond recommends washing of the animal's flanks, belly, tail, and udder with a chlorine disinfectant. As it is the first few streams of milk from each teat that contain most of the bacteria, they should be discarded either into a calf-bucket or into some other type of container, but not upon the ground. Unsterilised milk utensils constitute the most important source of contamination. After sterilisation the utensils should never be dried with cloths. In dealing with tests for quality, C. K. Johns says that the plate-count is still the most satisfactory method for low-count milks, but it reflects only a highly variable proportion of the actual number of bacteria present. For incoming raw milk the direct microscope test--the Breed count--has advantages over the plate-count in that it is cheap, speedy, and can be carried out on large numbers of samples. It often shows the type of the bacteria present. On the whole Johns prefers dye-reduction tests, which are as accurate as counting methods and give an indication of the state of activity of the bacteria. Poorly cooled milk will

* Canad. publ. Hlth. J., April, 1941. 53