The myth of "an apple a day keeps the doctor away"

While it is true that most of us, when traveling, think we pay sufficient attention to what we eat and drink (a disproven indication considering the incidence of gold-fecal transmitted diseases in travelers) it is certainly true that when we feel safe at home we all let our guard down.

Useful microorganisms are normally present in foods as they aid in their preparation and digestion: for example, cured meats, cheeses, and wine owe their "goodness" to the action of bacteria. Sometimes, however, "pathogenic" microorganisms, namely bacteria, viruses, parasites, harmful to human health, can be present in water and food contaminating them, in different ways. Contaminated foods, once ingested, can cause illness if the microorganisms manage to overcome human defense barriers.

Pathogenic microorganisms can:

• already be present in the food at origin, such as in the meat or products of infected or diseased animals; on plants, irrigated with contaminated water or coming into contact with contaminated soil;
• contaminating the food at various stages of preparation due to:
  • handling with dirty hands by persons transporting or handling such food;
  • use of non-potable or, otherwise, contaminated water;
  • contact of the food with unclean work surfaces, utensils, containers;
  • use in the preparation of polluted ingredients or subsequent contact with them;
  • exposure of the food, after preparation, to insects, rodents or other animals

The occurrence of a disease depends on the outcome of the "battle" between the pathogenic microorganism and the "defenses" of the human host. The microorganism deploys, among its weapons:

• "pathogenic power," i.e., its more or less ability to procure harm;
• its "charge," that is, the number of microorganisms present in a food; for certain diseases to develop, it is necessary, in fact, that a high number of microorganisms be ingested;
• its "mobility" and the ability to spread the toxins produced: sometimes, in fact, only a portion of a food is contaminated, which, if ingested, is harmful only to the person who consumed that particular portion.

Humans, on the other hand, have the ability to oppose the damage caused by microorganisms with numerous defenses that depend on age (children and the elderly have them weaker), the general condition of the body, states of stress, and other diseases present.

Generally, the greater the amount of contaminated food ingested, the greater the chance of manifesting the disease although, for some intoxications, such as botulism, it is sufficient to ingest very small parts of food.

Diseases caused by food are numerous (bacteria alone cause about 250). Contaminated food can play several roles in causing illness, such as:

1. being the indispensable element in the chain of transmission: some microorganisms cause disease only if they reach such a "charge" that they overcome human defenses; this charge is reached when the microorganisms find in the food the ideal conditions (temperature, humidity, acidity, content of sugars and salts, presence of oxygen) to multiply. The harmful action of microorganisms can be realized, therefore, either by ingestion of the microorganism along with the food (in which case there will be FOOD TOXINFECTION), or through the toxins they produce (there will then be FOOD INTOXICATION); the most frequent food toxins in our country are Salmonella toxins, Clostridium perfrigens toxins, Bacillus cereus toxins; while the most frequent food intoxications are: Botulism and Staphylococcus aureus intoxications;
2. be an occasional element in the chain of transmission: contaminated foods, may function as simple carriers ("vehicles") of the microorganisms with which they have come in contact, without the need for them to multiply in the food; for the transmission of these diseases an important role is played by direct contact between the secretions of sick individuals with healthy individuals. More generally they result from contamination of food and water with fecal material from sick people or carriers.

In these cases we speak of FOOD-borne DISEASES among which the most frequent in our country are hepatitis A and typhoid fever; in tropical countries, increasingly often tourist destinations, shigellosis, escherichia coli diarrheas, cholera, amebiasis, giardiasis are widespread; - coming from infected animals: again, food is only one of the possible vehicles; diseases transmitted from sick animals to humans (ZOONOSIS) are also transmitted by handling animal flesh or its derivatives. Among these diseases, brucellosis, trichinosis, and tularemia are common in our country.

Here are some diseases transmitted through improperly handled foods:

• hepatitis A
• typhoid fever
• Escherichia coli infections
• cholera
• amebiasis
• giardiasis

Waters and foods contaminated with feces or urine of diseased individuals or "carriers"; most often these are seafood raised in contaminated water or washed with dirty water and consumed raw or not well cooked, fruits and vegetables irrigated with contaminated water, unpasteurized milk and dairy products; the occurrence of any of these diseases always testifies to a poor level of hygiene in food production, preparation or handling.

Toxic infections and food poisoning, with the exception of botulism, generally manifest themselves with a very similar symptomatology in the gastrointestinal system (stomach and intestines).

It is necessary, upon the occurrence of these situations, to immediately contact a specialist who, in relation to the symptoms, the information gathered and any tests, will be able to make the diagnosis and prescribe the most appropriate treatment. If a case of botulism occurs, it is advisable for all those who have consumed the suspected food to contact the treating physician.

It is absolutely inadvisable to self-medicate with antibiotics in cases of diarrhea, vomiting or fever of unclear origin: if these symptoms are related to the presence of microorganisms in the intestines, the use of an inappropriate antibiotic, by destroying the bacterial flora normally present, promotes the development of pathogenic microorganisms.

All people experiencing diarrhea should scrupulously adhere to common hygienic rules, taking careful care of personal hygiene; hand washing is most important and should be done with warm water, soap and a nail brush after using the toilets. It is advisable to clean the toilets, and everything that comes in contact with the sick person's vomit and feces, with chlorine derivatives: common bleach, used undiluted or at low dilution, is an excellent disinfectant. Handling food should be avoided during the period of illness. If it is suspected that the basis of the symptomatology is the consumption of particular foods, it is advisable not to throw away the residues but to keep them aside in the event of an analysis conducted on them.

Sources:

• Salute.gov
• Health.gov