82 REVIEW — TROPICAL MEDICINE, ETC. 



Food — The most dangerous tinned foods are those eontiiiniiig much moisture, i.e. milk, salmon, lolistor and mixtures 



continued °^ meat and vegetables. 



The more acid foods, sueU as fruit, jams and vegetables, are more liable to take up metals from the tins. 

 The simpler tlic preparation, the bettor it stands the effects of climate and heat. Useful notes on inspection are 

 given. Apparent l>iilging may Ijc due to the tins being dented. A good tin of meat has usually sliglitly concave 

 ends owing to a partial vacuum forming during the process of sterilisation. 



Ee-solderiug should be looked for. As a rule, two holes are made in one end of the tin to permit steam to 

 escape. Re-soldering, or the presence of a third or more soldered holes points to puncture to allow gas to escape. 



Dented tins, if otherwise fit, should be issued early, as they are apt to rust and perforate on keeping. 



On opening certain tins, i.e. of marmalade, rhubarb, tomato soup, etc., a blackened appearance may be 

 noticed. This is due to the action of the vegetaljle acids on the tin-plating, and if slight, and there is no evidence 

 of fermentation as evidenced by minute gas buljbles, may Ije neglected. 



Decomposition may result from incomplete sterilisation, or incomplete sealing of the tin. Bulged tins, may be 

 tested liy puncturing them under water to test for the escape of gas. In some cases, a little gas will escape from 

 tins euutaiuing perfectly sound meat, owing to incomplete exhaustion during the process of sterilisation, Init 

 which, being sterile, is of no real consequence and amounts to, as a rule, only about 1 c.c. or so. One test 

 described is as follows : — When the swelling is not apparent, the tins are boiled for one hour, which causes, by 

 expansion, the ends of all to swell ; they are then cooled and set aside for eight hours, when the sound ones 

 will return to their former condition. The unsound ones will remain liulged as the convexity is due to the 

 pressure of gases. Viry states that putrefaction may take place in tinned meats without tlie formation of gas, 

 but Beveridge has not been able to confirm this. The presence of moulds at once condemns, the sterilisation 

 not having been efficient. Moulds impart an unpleasant taste to the food and are apt to cause diarrhoea. 



Eber's test for the decomposition of meat is said to be useful but not absolutely reliable, owing to the 

 presence of trimethylamine, in, for instance, mutton and pickled foods. A small quantity of the reagent, which 

 consists of one part sulphuric ether, one part pure liCl. and three parts cthylic alcohol, is placed in a test-tube or 

 other suitable vessel. The material to be examined is smeared on the end of a glass rod, which is dipped below 

 the sm-faee of the reagent but is not allowed to touch the side. If ammonia be present, a cloudiness appears or 

 fumes may be given off. 



Food Poisoning. This is a subject of very considerable importance in all hot 

 countries, and one has seen several examples of it in the Sudan. It may result from : — 



1. Faulty preparation of food, as from dirty kitchen utensils, the dirty hands of cooks 

 and their assistants, imperfect or defective cooking, or the addition of deleterious substances, 

 either designedly or accidentally. 



2. Decomposition vyhich is very apt to occur, especially in foods kept over-night. 



3. Contamination, apart from preparation, i.e. from faulty storage or from the filthy 

 feet of flies or other insects. 



4. Injurious food-stuffs, such as bad tinned foods or imperfectly cured or preserved 

 foods. 



I recall an epidemic occurring at the Grand Hotel, Khartoum, and in this connection 

 Walker's paper' on the so-called "Canary Fever" of Las Palmas is specially interesting. 

 He has shown that this condition is in all probability due to bacterial infection of food. It 

 is peculiar by occurring in hotels, coming on suddenly, and attacking a number of hotel 

 residents at the same time. It is characterised by vomiting or nausea, followed by diarrhoea, 

 and the stools may contain mucus and even blood. The temperature may rise, but not as a 

 rule to any considerable extent. The length of attack varies from two days to three weeks. 

 The causes are discussed, and I quote here in full the preventive measures recommended, 

 because I think they are specially applicable to the hotels and numerous restaurants in 

 Khartoum, and because it has been found necessary in certain cases to enforce the adoption 

 of somewhat similar precautions : — 



Meat and fish, particularly, should be protected from flies in as effective a manner as possible before it is 

 brought into the hotels. 



When in the hotels all food should be protected from flies; the larder should be entirely fly-proof; the 

 entrance should be protected by two doors, between which there is room for a man to stand ; both these doors 

 should close automatically with springs, and it would be well to have some simple automatic arrangement which 

 would prevent one being opened until the other was closed. It should be easy to catch the few flies that might 

 possibly get into the larder, in spite of these precautions, by means of fly tr.aps. 



Of (rourse the best plan would bo to keep the food in a chamber which was constantly below fi'cezing-point. 

 When the food was removed, once or perhaps twice during the day, it should be kept in fly-proof receptacles. 



Meat should be kept hanging up, and not laid upon shelves. 



Shelves and tables in the larder, serving rooms and kitchens, should be made of some non-absorptive material, 

 such as marble or slate. Most of the shelves and tables upon which the food was placed during the process of 

 cooking and serving, which I saw in the islands, were made of soft wood. No matter how much this wood be 



• Walker, C. E. (February 29th, 1908), " Observations on the so-called ' Canary Fever.' " Annals of Tropical 

 Medicine mid Parasitology, p. 483, Series T.M., Vol. I., No. 4, Liverpool. 



