How long does it take for food poisoning symptoms to emerge

The number of people hospitalized with listeriosis is decreasing, but 20 days after the health alert originating from the mecha meat from the company Magrudis was activated, new positives in the disease continue to be confirmed. The last one was known yesterday, in Granada, at the same time that the news emerged that six people have been affected by the same outbreak in Germany. The period between eating contaminated food until the first symptoms of food poisoning appear can be very long, as the case of shredded meat has shown, but this is not always the case: the time varies greatly, from 6 hours to which salmonellosis can debut until the 70 days that can elapse until listeriosis manifests.

According to the microbiologist of the National Center for Microbiology Silvia Herrera, “the response of the population to a food toxinfection depends on the infective dose of the pathogen involved and the type of food consumed.” Specifically, it varies according to the number of bacteria that it is necessary to ingest to produce the infection, and it must be borne in mind that certain pH, temperatures, salinity or water content of the food can favor a massive growth of the bacteria.

In addition, there are people more prone to suffer infections of this type or who suffer more serious consequences. “The main vulnerable groups are babies and children, because their immune systems are not fully mature. WomenPregnant women are also especially vulnerable to foodborne infections, and although toxin infection can often be asymptomatic for the mother, transmission to the placenta can have consequences for the fetus and newborn. So are the chronically ill or those with a depressed immune system who are under treatment with immunosuppressants and people over 65 years of age, who have a weakened immune system and an increased risk in the cooking practices they carry out, mainly due to deterioration. of senses such as smell and taste, which can make it more difficult to identify food in poor condition, “says Ana Fuertes, food safety expert at the microbiological diagnostic company bioMérieux Iberia.

All in all, the incubation periods for the most common toxinfections in Spain can be calculated by the pathogen that causes them, which helps to detect the origin of the problem, and, according to the experts, are as follows.

Salmonella, from 6 to 72 hours

The action of this bacterium is very fast, so much so that it can cause salmonellosis before reaching the next meal; the incubation period is from 6 to 72 hours, although the average is usually between 12 and 36 hours. The symptoms of Salmonella infection usually begin in the form of diarrhea that can be accompanied by fever, nausea, vomiting, headache, myalgia and other symptoms. In healthy people, this condition resolves after 3 to 7 days, but in individuals in the risk groups it can progress to septicemia or a localized infection, and produce various symptoms that depend on the organs in which it is found. settle infection. The normal thing is that the fever do not exceed 48 hours, while diarrhea can remain up to seven days in some cases, especially in the elderly and children, and the condition of the sick can be so serious as to enter the hospital.

Campylobacter, 2 to 5 days

It is the most common bacterial cause of gastroenteritis worldwide, and one of the top four of diarrheal disease, according to data from the World Health Organization. Its incubation period is from 1 to 10 days, and its clinical symptoms usually last between 2 and 5 days. Most cases occur in summer, in healthy, adult people, and the infection is usually asymptomatic. If symptoms appear, they are usually diarrhea (often feces contain blood), abdominal pain, discomfort, fever, nausea and vomiting.

“The problem, again, comes when the bacteria reaches people who have a weakened immune system, as it sometimes spreads into the bloodstream and can lead to a serious infection, which is life-threatening. Because of this bacterium, cases of hepatitis, pancreatitis (infections of the liver and pancreas, respectively) and spontaneous abortions have been reported, “says food security expert Ana Fuertes. He adds: “Post-infection complications can include reactive arthritis (a painful inflammation of the joints that can last for several months) and neurological disorders such as Guillain-Barré syndrome, a form of paralysis that can lead to severe respiratory and neurological dysfunction. ”

Escherichia coli, 10 hours to 8 days

Better known by the abbreviation E. coli, it is a bacterium present in the intestine of warm-blooded organisms; that is, it lives in the digestive system of human beings. Most of its strains are harmless, but some acquire a virulence that can translate into serious food poisoning. These groups of pathogenic E. coli are classified according to the virulence factors they acquire, and have different characteristics in their incubation times and the symptoms they produce. The group most frequently associated with food toxinfections in Spain is the ECEH group (enterohemorrhagic E. coli), which is usually associated with consumption of raw meats, unpasteurized milk and contaminated vegetables.

The EHEC incubation period is 1 to 8 days, and the most common symptoms are bloody diarrhea, abdominal pain, short-term fever, and vomiting. In most cases, these symptoms resolve within 4 to 10 days, but hemolytic uremic syndrome, a disorder in which infection in the digestive system produces toxic substances , can occur in 10% of cases. they destroy red blood cells and cause kidney damage.

Less frequent are the clinical pictures produced by the other groups. The incubation period for ECET (enterotoxigenic E. coli) is very short, between 10 and 72 hours. The main symptoms are very abundant watery diarrhea, with vomiting and abdominal cramps and light fever. It generally lasts less than 5 days. In the case of ECEP (E. coli enteropathogen), the incubation period is 3 to 24 hours, ECEA (E. coli enteroaggregative) has an incubation period that fluctuates between 20 and 48 hours and ECEI (E. coli enteroinvasive) , between 10 and 18 hours.

Listeria, between 3 and 70 days

The incubation period leading to listeriosis is extremely long; It comprises between 3 and 70 days, and the average is 3 weeks. The difference is explained because listeriosis can present as non-invasive gastrointestinal or as invasive. “The first occurs in immunocompetent people (with a strong immune system), generally after ingestion of high doses of the bacteria, a case in which the incubation period is usually short, as is the case with other foodborne diseases But in invasive listeriosis, the one that occurs more frequently in risk groups, the incubation period is longer because the battery has to access the central nervous system and the placenta, “says Herrera.

Listeriosis usually goes unnoticed in healthy adults, and in some cases it manifests with symptoms similar to those corresponding to a mild flu, such as fatigue and muscle pain, or occurs in the form of gastroenteritis. But it disappears spontaneously because the bacteria have not spread through the bloodstream or other areas of the body. “However, in a young but pregnant person, for example, listeriosis can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn,” explains Fuertes.


Vomiting, persistent diarrhea, severe abdominal pain, fever above 38ºC, dehydration and neurological symptoms such as blurred vision, tingling in the arms and lipothymia are symptoms that, according to the specialist in the digestive system at the ServiDigest clinic Patricia Goncalves da Cunha, they give us the signal that we should go to the emergency room. “These cases are normally treated with adequate fluid and electrolyte replacement, antiemetics, astringent diet and rest, but the most severe cases require hospital admission, intravenous hydration and antibiotic treatment,” he points out.


Leave a Comment