How is salmonella contagious

Salmonella: transmission

Enteric Salmonella is transmitted worldwide through food that has been bacterially contaminated with animal waste products. Since the number of germs required for an infection is very high, the bacteria usually have to multiply in food. Transmission through drinking water is therefore considered to be exceptional and only occurs when the drinking water is extremely contaminated with faeces. Direct transmission from person to person is also unusual. Although infected people excrete a large number of bacteria in their stool, it is only in rare cases that they become infected through poor hygiene when sharing the toilet. Patients infected with enteritis salmonella usually excrete the pathogens only a short time (on average one month) after infection. Longer periods of up to a year are rare and occur especially in young children. In contrast to typhus, there are no "permanent excretors".

The bacteria have the property of being able to grow with oxygen (aerobic) and without (anaerobic). Salmonella multiply at temperatures between 10 and 47 ° C, less often from 6-8 ° C. They are very resilient and can survive for months in certain foods and even withstand sub-zero temperatures, e.g. when freezing. Only heating the food to at least 70 ° C for at least 10 minutes by frying, baking, boiling etc. will kill the germs.

Spread through poor hygiene

The propagation takes place as a rule by hygienic, i. H. Too warm or too long storage of food or interruption of the cold chain during transport. Touching and processing infected food can contaminate other foodstuffs, kitchen appliances and people (cross-contamination). Spatially close animal husbandry supports Salmonella infestation at the beginning of the food chain. Transmission from farm animals directly to humans or from person to person is very rare.

The primary sources of infection are contaminated food from poultry, cattle or pigs. The animals themselves are not affected by this. The leading causes are almost all types of poultry, raw eggs and dishes that contain raw eggs. These include in particular dessert creams, confectionery and mayonnaise. The salmonella can sit in the egg as well as on the shell. Ice cream and frozen food are also considered risk products. It is now believed that the causes of outbreaks in the recent past can also be found in sprouts, tomatoes, herbal teas and smoked eel, for example.

Stomach acid kills the bacteria

Since stomach acid has a bacteria-killing effect, this barrier can only be overcome by high bacterial counts: there are normally more than 10 to infect a healthy adult4-106 Bacteria required. Patients who take drugs that block gastric acid are also at a higher risk of infection, as significantly fewer germs are sufficient to trigger an infection. In people with a weak immune system, small children, old or sick people, illnesses are already present at a dose of 102 Germination has been observed. Likewise, when eating foods with a high fat content (chocolate, salami, cheese, etc.), a lower number of germs is sufficient for infection.