Food Infections

FOOD INFECTIONS, POISONINGS, diseases in which food is typically the main means of transmitting infection or poisonous substances to humans or at least gives the disease a special character related to the transmission of the disease-causing agent specifically through food. Therefore, the concept of 'food infection' does not apply to cholera, typhoid fever, dysentery, and other similar diseases, where food as a vector of infection plays far from the main role, and sometimes even a secondary role. On the contrary, one can speak of food-borne anthrax, since its intestinal forms are exclusively of food origin (see Anthrax). If the clinical picture of the resulting disease is dominated by phenomena characteristic of the infectious process (incubation, temperature, corresponding changes in organs, multiplication and excretion of pathogens), then such a food disease is called a 'food infection.' On the contrary, in cases where phenomena of body intoxication come to the forefront (sudden onset, rapid course, absence of a specific pathogen, phenomena of the central nervous system, etc.), the disease is classified as 'food poisoning.' It is not always possible to draw such a strict line, since sometimes human food infection depends not only on the multiplication of pathogenic microbes in the body but also on the absorption of toxins contained in the food, produced by these microbes. Therefore, one must recognize the existence of a special group of toxo-infectious diseases, which is transitional between food infections and food poisonings. Practically, these groups of diseases are even more narrowed down, since only cases where the severity of the disease and the large number of victims attract attention are recorded. Thus, it should be recognized that individual and mild cases of food infections and poisonings often escape the attention of both the patients themselves and statistical institutions. The question of the nature of acute diseases caused by food was not immediately resolved with sufficient clarity. Thus, in the pre-bacteriological period, the view of Hübener prevailed for some time, who believed that meat poisonings, for example, occur due to hydrocyanic acid, which forms in meat under some unexplained conditions. Jean Jacques Rousseau considered copper, which passes from utensils into the food product, to be the cause of food poisonings. These one-sided views were refuted by all the data of everyday observations and therefore did not last long. The experiments of Albrecht von Haller, Panum, Bergman, and Schmiedeberg acquired great importance, studying the toxic properties and nature of chemical substances formed during meat decay. Selmi first introduced the term ptomaines for these substances, which had the properties of alkaloids and chemically were bases (see). This theory gained particular popularity due to the works of Nencki, Brieger, and other authors, who studied many poisonous ptomaines isolated from decaying products. In addition, a whole series of scientists, led by Gautier, established that the cells of animal organisms themselves (independent of microbes) produce various chemical substances, many of which are bases, have the properties of alkaloids, and are extraordinarily poisonous to animals. These bodies were named leukotoxins on the proposal of Gautier. Recently, however, even this ptomaine theory has begun to cause great doubts, since contrary to the opinion of the mentioned authors, facts were constantly observed indicating the frequent harmlessness of decaying products, and on the other hand, it was definitely clarified that sometimes food, completely impeccable in appearance and taste, was the cause of fatal diseases. In the further development of the question of the essence of food poisonings (infections), Bollinger played a major role, who appeared at the Union of Public Hygiene in Düsseldorf in 1876 and in Munich in 1880 with a report on the connection between pyemic and septicemic diseases of domestic animals, on the one hand, and mass diseases observed after people consumed meat of such animals, on the other. He substantiated his opinion with observations on 17 epidemics of meat poisonings with 2,400 individual cases and 35 fatal cases. Thus, this author first drew attention to the importance of the animal's condition during life. Although Bollinger himself understood the problem he touched upon somewhat narrowly, nevertheless his view contained a large share of truth and served as the basis for further development of this issue. After Bollinger, other authors tried to link food poisonings with some disease-causing agent present in meat, but this doctrine was fully substantiated since the discovery by Gartner of a microorganism isolated by him during an outbreak of meat poisonings in Frankenhausen in 1880 in a case of fatal poisoning of a person by meat. This microorganism was isolated both from the human body and from the organs of the animal from which the meat came, and was named Bacillus enteritidis. Soon, namely in 1895, in Belgium, van Ermengem, while studying an outbreak of food poisoning in Ellezelles, managed to isolate from the spleen and stomach contents of a deceased person a special anaerobic microorganism, which he named Bacillus botulinus. These discoveries gave a new light to the question of food poisonings and showed that the cause of the disease-causing properties of food can be bacteria that enter the food product and develop in it under the most diverse conditions. It cannot be said that even to the present time all this is completely clear, nevertheless the question of food poisonings and infections is now understood in a much more definite way. All diseases belonging here can be presented in the form of the following scheme. I. Food poisonings of chemical nature: 1) poisoning by a food product poisonous in its nature, 2) poisoning by a temporarily poisonous food product, 3) poisoning due to the admixture of a poisonous substance to the food product. II. Food poisonings of bacterial nature: 1) toxic poisonings - botulism, 2) toxo-infectious diseases: a) diseases caused by proteus (Bac. proteus), b) diseases caused by the group of intestinal bacilli (Bact. coli and Bact. paracoli), c) diseases caused by the group of paratyphoid microorganisms (Bact. paratyph. B. Breslau, Bact. enteritidis Gartner's, Bact. suipestifer). III. Food infections: a) tuberculosis of food origin, b) septic inflammation of the pharynx of milk origin, c) Malta fever, d) anthrax of food origin and others. IV. Food poisonings of unknown nature. V. Food idiosyncrasies. VI. Psychogenic food diseases. I. Under food chemical poisonings are meant the following categories of cases. 1. Poisoning by a food product poisonous in its nature: for example, poisoning by poisonous but under certain conditions edible fish (marinka fish in Lake Balkhash), unroasted beech nut containing a harmful substance - phagin (chemical nature not yet clarified), etc. 2. Poisoning by a food product that has temporarily acquired poisonous properties, which as a rule are usually absent. This includes cases of poisoning by fish that only temporarily at a certain period of their life (most often during spawning) develop poisonous substances in themselves, and in these fish usually only certain internal organs are poisonous: roe, blood, liver. Among such fish are burbot, haddock, pike, etc., in which the roe is poisonous; perch, mackerel, etc., in which the liver is poisonous. Cases of poisoning by sprouted potatoes, containing in their peel and sprouts a large amount of the poisonous glycoside solanine (see Potato), should also be included in this category of cases. 3. Poisonings arising from the presence of poisonous impurities in the food product itself, such as poisoning by bread baked from flour containing a large amount of ergot, charlock, and other poisonous vegetable impurities. Sometimes a poisonous substance enters the food during its processing; in these cases, the poison can pass into the food product either through utensils (lead into the contents of canned goods with improper manufacture of the tin box, copper from poorly tinned kettles, lead from improperly made glaze, zinc when making acidic dishes in galvanized dishes) or due to insufficient purity of auxiliary substances used in the processing of the food product (arsenic with acetic acid or impure molasses, amyl alcohol with pear essence, etc.). Poisonings due to the accidental entry of a chemical poison into food (for example, in the fight against rodents) can also be included here. If a chemical food poisoning is sufficiently pronounced, then establishing its nature is possible in most cases, although not entirely easy. Less pronounced symptoms often pass unnoticed or under other names.

The element of mass occurrence and suddenness of diseases is observed in this category of cases quite often (poisonings of children in a children's home from jelly made in galvanized vessels, poisoning from ice cream containing a large amount of improperly prepared pear essence, etc.). A striking example of mass chemical poisoning is the disease that occurred in Liverpool in 1901 among 6,000 workers (with 70 cases of death), who drank beer containing arsenic due to the impurity of the raw material - molasses. The clinical picture and treatment in chemical poisonings are diverse (see Poisoning, Poisons). II. A large group of food poisonings of bacterial nature can at present be divided into several subgroups according to the etiological factor and clinical picture (see above). The microbes involved in food poisonings and infections are quite widespread in nature and are found both in the intestines of the animals themselves used for food (microbes of the paratyphoid group - in the intestines of cattle) and in the environment that contaminates the food product (botulism microbe in the soil). Not for every food product are both paths of infection equally significant. In meat, for example, one or another pathogenic inhabitant of the intestine may appear due to colonization in the animal's body during any of its diseases, even during prolonged agony, and only in much rarer cases can it be passively transferred by a person, a piece of contaminated carcass or other material to a completely healthy food product. In the case of contamination of vegetable preserves with botulinus spores, on the contrary, the transmission of infection occurs passively through the soil and the contaminated surface of the vegetables. As can be seen, the number of agents capable of causing food poisoning is quite large, and yet there is something common in all cases of food poisoning (of bacterial nature) that allows them to be singled out as a special group. Below are some features of outbreaks of these diseases. It should however be said that these features are expressed to varying degrees, and therefore they should be understood to some extent conditionally. They are most sharply noticeable in outbreaks caused by highly pathogenic and toxic agents (Bact. botulinus, Bact. enteritidis, Gartner), and less so when less dangerous microorganisms (Bac. proteus, Bact. paracoli) are present in the food product. In general, outbreaks of bacterial food poisoning differ in most cases by the following features: 1) suddenness of onset, 2) mass occurrence of diseases, with the majority of persons becoming ill simultaneously or almost simultaneously, 3) all cases of disease in one epidemic are associated with a homogeneous food product, and sometimes even with one sample that caused the poisoning, 4) the diseases are territorially concentrated in the area, street, production facility, dormitory, served by a store or other institution (canteen) that distributed the pathogenic food product, 5) the contact method does not play a role as a means of spreading the disease among the population, 6) after eliminating the object that caused the poisoning, the appearance of new diseases sharply ceases, in accordance with which the curve of the entire food poisoning epidemic has a sharp rise and a sharp fall. Ordinary gastrointestinal epidemics, on the contrary, spread more or less widely depending on the method of transmission of the infection (wide dissemination in water epidemics and more limited dissemination in other routes of spread), it is often possible to note a contact origin; finally, epidemic gastrointestinal diseases give a declining curve, gradually descending to zero. The food product that could have been the cause of the first cases of infectious diseases may not play a role in the future. The epidemic can spread by other means (see Infection). If bacterial food poisonings are compared with each other in different countries, a certain difference can be noted between them; thus, in America the main object causing poisonings is vegetables, in Europe - meat, and in the USSR - fish. This difference is explained by several reasons. In America, the influence of two factors is combined: the highly developed vegetable canning industry and the contamination of the soil to a large extent with the botulism microbe (about 30% of all samples examined). B. botulinus spores, in some cases withstanding the sterilization of tin cans with vegetable preserves, germinate during further storage of the preserves and form a strong toxin. In Western Europe, the reason for more frequent poisonings from meat is the rather common custom of eating meat in a semi-raw state. Finally, in the USSR, fish is most often eaten in a semi-raw state. Although the scientific classification of bacterial food poisonings according to the etiological factor is the most well-founded, from a practical point of view it is important to characterize these food poisonings also by individual products, since each product can give its own characteristics to the resulting outbreak of acute diseases. In this regard, the most interesting and important are meat, fish, and vegetable poisonings. Meat poisonings (see) are best studied in Germany, and on German material a number of interesting details can be identified. If in the description of meat poisonings one has to base oneself on German material, then for the characterization of fish poisonings one can to a large extent rely on Russian material. Since 1885, a total of 60 cases of fish poisoning have been described, which are grouped in the following table: Quantity Location Years of patients Quantity deceased Product Diagnosis established Unknown Salted sturgeon Clinically and toxicologically Rostov-on-Don Salted herring Clinically Salted sturgeon Clinically and toxicologically Astrakhan .... Sturgeon, salmon Clinically and toxicologically Unknown Clinically Astrakhan .... Whitefish Bacteriologically and toxicologically Lightly salted whitefish Clinically Boiled sturgeon Clinically Smoked herring Clinically and toxicologically Fresh sturgeon Clinically Fresh sturgeon roe Clinically Smoked herring Clinically and toxicologically Dried sturgeon Clinically and toxicologically Yaroslavl .... Lightly salted sturgeon Clinically and toxicologically From these data it is evident that, first, the cause of fish poisonings is fish that can be eaten in an uncooked state (salted, dried, and smoked samples), and second, poisonings more often occur from the consumption of red fish. The etiology of fish poisonings was clarified after the discovery by Konstantsov in 1913 of a microbe in whitefish, which was the cause of two fatal diseases, very closely related to B. botulinus described by van Ermengem. At present, most authors believe that fish poisonings are the result of the formation of toxins in the fish by a microbe or an agent identical to or very closely related to the botulism microbe (see Botulism). The works of Ruchkovsky with great probability clarified the reason for the particular frequency of fish poisonings from red fish meat. It turned out that sturgeons are particularly resistant to botulinus toxin (they can withstand up to 250,000 doses lethal for a guinea pig), and the meat of poisoned sturgeons that remained completely healthy can cause death when an infusion is introduced into the abdominal cavity of a guinea pig. Non-sturgeon fish does not have such resistance and dies from 500 to 15,000 lethal doses. It was also found that botulinus toxin can form both when red fish is infected orally (with washed spores) and during its life (not always) and after death, and in the latter case the toxin in the meat can be detected by biological experiment only after 24 hours of storage of the fish together with the infected intestine. From this Ruchkovsky rightly puts forward the theory of the development of toxicity after the catch of the fish due to its prolonged stay in an uneviscerated state. Fish poisonings belong to the category of the most severe and give a very high mortality rate (up to 67%). The clinical picture completely coincides with what is observed in botulism in general. The third type of bacterial poisonings of great importance are poisonings from vegetables, or rather vegetable preserves. They are particularly common in America due to the heavy contamination of American soil with the botulism microbe (type A). Poisonings from vegetable preserves occur especially frequently when consuming homemade preserves. Of all cases of food poisonings, according to Knorre (Knorre), in America 68% are from vegetable poisonings, while in Germany about 4%. Depending on the etiology (botulism microbe), the mortality observed in vegetable preserve poisonings is very high (up to 60%). Here mention should also be made of cases of food poisonings caused by vegetables consumed in the form of salad, vinaigrette, etc. As the contaminated object, potato sometimes plays a role. Bacteriological research has shown that in these cases potato is infected with proteus.

Savage believes that this type of contamination of potatoes can occur especially frequently when stored in a peeled state, as such potatoes are an excellent nutrient medium. III. Food Infections. As stated above, the concepts of food poisoning and food infections are difficult to distinguish. An example of this situation can be meat poisoning, where after the typical toxic effect of the toxin, a secondary infection with developed enteric bacilli can sometimes occur, which, according to Standfus, can lead to a complication of the process. Nevertheless, a number of infections can be cited that do not cause poisoning phenomena, and therefore it is possible to speak of their delineation. These should include: tuberculosis of food origin, septic inflammation of the throat caused by milk, Malta fever, food-borne anthrax, etc. Although not all microorganisms causing these food infections are specific only to the food product, the specific clinical picture of the disease that has arisen depending on the transmission of infection through food makes it possible to call these special infections food-borne. IV. Food Poisonings of Unknown Nature. Much less data can be provided in characterizing food poisonings that occur from the consumption of cheese as well as oyster meat. To this day, the exact cause of poisoning for these products has not been clarified. Briger suggested that cheese gets its poisonous properties due to the presence of a large amount of trimethylamine, Vaughan considered the toxic principle of toxic cheese to be a special substance isolated by him (tyrotoxin), which does not belong to the alkaloids. Even less data is available to judge the nature of poisonings that occur when consuming oyster meat. A number of authors assumed that the poisonous properties of oysters should be attributed to various harmful substances adhering to them from the outside or eaten by the shells. According to Briger, shells become poisonous due to the process of decay, which they supposedly undergo even during life in the hot summer months during their reproduction. Schmidtmann noticed that poisonous shells predominantly multiply in the stagnant water of harbors. Completely healthy shells, when transplanted into this water, after some time become highly poisonous. Damon believes that this circumstance rather depends on the contamination of the shells by bacteria that have formed toxins poisonous to humans who consume the shells as food. V. Food Idiosyncrasies. This category includes diseases that arise in connection with increased sensitivity of some individuals to the normal composition of certain food products (crayfish, strawberries, etc.). These diseases at first can sometimes simulate mild food poisonings (see Idiosyncrasy).--VI. Psychogenic food poisonings are cases of the occurrence on the basis of special suggestibility of a symptom complex characteristic of food poisoning after the consumption of completely harmless food. As is known, the diseased state of a food product is most often discovered after its poisonousness has been proven in humans. The difficulty of preliminary determination of harmfulness often lies in the absence of any indications for investigation, as well as in the complexity of the investigation itself. Therefore, prevention in this area should be transferred not only to places of product distribution, but mainly to places of its procurement. Slaughterhouses, sausage factories, canneries, salting stations, and fishing enterprises should be under constant and vigilant supervision. The role of slaughterhouses and fisheries should be particularly emphasized, from the sanitary condition of which depends the release of fresh, impeccable food products. Along with controlling organizations monitoring the state of affairs in the aforementioned institutions, it is necessary to rely on sufficiently informed sanitary personnel who could in each individual case specifically decide on the necessary measures to eliminate the outbreak that has arisen, as well as on the possibility or impossibility of allowing suspected food products into food. The sanitary physician should base his conclusions on the sanitary and laboratory study of the food market, and therefore should be provided with a sufficiently well-equipped chemical and bacteriological laboratory. Finally, to assist in the prevention of food poisonings, and should increasingly serve, food legislation, both along the lines of health authorities and veterinary administrations and other departments (see Food Legislation). The object of attention of food legislation should be not only production itself, not only raw materials, semi-finished products and the final product, but also the conditions for allowing various so-called 'conditionally suitable' and 'less valuable' products into processing, and therefore into food. Clarification in this area and revision of old provisions on the basis of the latest scientific data are a direct and urgent necessity. A correctly organized registration of these diseases, which has not yet been sufficiently organized, must play an enormous role in the fight against food poisonings. In 1931, the People's Commissariat of Health of the RSFSR gave corresponding instructions to its bodies. When it becomes necessary to investigate a food product in connection with food poisoning, it is necessary to keep in mind three lines in the investigation of the suspected object, namely: chemical, bacteriological research and biological testing on animals. Sometimes the product itself, the attendant circumstances (typical picture of poisoning) and other circumstances make it possible to simplify the task and to engage in two or even one side of the research, but in those cases where these facilitating circumstances are not present, it is necessary to study the product comprehensively. And yet even with such a complete study of the object, only positive cases can be conclusive. A negative result of the investigation by itself does not solve the question in the vast majority of cases. This situation depends on the great difficulty of correctly selecting a sample for investigation (the poisonous part may already be absent), as well as the imperfect research methodology. All cases of death from food infections or food poisonings, as well as suspicious cases in this regard, should be the reason for a forensic autopsy to determine the actual cause of death, in particular to exclude other poisonings, for example for the purpose of suicide or murder (see Poisoning).