Salmonella: the causes, symptoms and treatment

The Food Standards Agency (FSA) has issued an urgent health warning over eggs being sold in UK supermarkets that may be contaminated with salmonella.

The food safety watchdog this week announced that an investigation into an increase in the number of salmonella cases in the UK had revealed the possible contamination of a specific batch of eggs verified under the British Lion scheme, which covers 90% of eggs sold in the UK.

The eggs in question have the unique flock code 1UK11871, with “best before” dates of 22 September 2019, 23 September 2019 and 24 September 2019.

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The FSA alert said it was “issuing precautionary advice to consumers who have purchased the eggs... to help avoid any potential, though low risk of illness”.

According to records seen by the Bureau of Investigative Journalism and The Guardian, regulations designed to ensure high standards in the sector were “breached several thousand times by farms, packing stations and wholesalers over the last three years”, with more than a hundred tests for salmonella “missed, or carried out too late, increasing the chance of contaminated eggs entering the food chain”, says the newspaper.

More than 50 egg-laying flocks have tested positive for salmonella since January 2018, of which 11 were contaminated with the most serious strains of the bacteria.

The investigation found that at least 100 people had been poisoned by British eggs in the past three years.

Responding to the revelations, Professor Erik Millstone, a food safety expert at Sussex University, said: “If 100 cases of salmonella poisoning from UK eggs has not been sufficient to withdraw the advice that UK produced eggs can safely be eaten raw, how many will be enough? How many people will need to get sick before the advice will be changed?”

What is salmonella?

Salmonella is a bacterium commonly found in the intestines of humans and animals. There are two main species - Salmonella enterica and Salmonella bongori - and despite the common belief that diseases caused by these two species are also called salmonella, the proper name for food poisoning derived from these species is salmonellosis.

According to Ireland-based information site Safe Food, the bacteria can also be found on raw meats, poultry, eggs and in unpasteurised milk. And other foods including green vegetables, fruit and shellfish can become contaminated through contact with manure in soil or sewage in water.

Salmonellosis can occur if live salmonella bacteria enters the body. This bacteria “can attach to the cells lining the intestines, where they produce toxins and attack the intestinal cells”, the site adds.

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How do you get it?

The NHS says that salmonellosis is usually the result of eating raw or undercooked food, particularly meat, poultry and eggs, or foods that have come into contact with contaminated produce. Infection is also possible from drinking unpasteurised, contaminated milk and even through contact with exotic pets such as reptiles, which can carry salmonella.

The US Food and Drug Administration has stated that some salmonella outbreaks have been traced to contaminants in spices.

How is it treated?

Most people with this form of food poisoning recover at home without treatment, and infections usually resolve within three to seven days.

The NHS advice for food poisoning is that “until you feel better, you should rest and drink fluids to prevent dehydration”.

“Eat when you feel up to it, but try small, light meals at first and stick to bland foods – such as toast, crackers, bananas and rice – until you begin to feel better,” the service adds.

However, medical advice should be sought if the patient is unable to keep down any fluids because they are vomiting repeatedly or if symptoms do not being to improve after a few days.

Symptoms of severe dehydration such as confusion, a rapid heartbeat, sunken eyes and passing little or no urine should be treated as an emergency.

How dangerous is it?

The symptoms of food poisoning usually begin within one to two days of eating contaminated food, although they may start at any point between a few hours and up to several weeks later.

The NHS says that the main symptoms include nausea, vomiting, diarrhoea, stomach cramps, abdominal pain, weakness, loss of appetite, fever and aching muscles.

In extreme cases, the diarrhea associated with salmonellosis can cause sufferers to lose so much water that they require urgent medical attention.

CNN adds that salmonella infections “can be life-threatening especially for young children, pregnant women and their foetuses, the elderly, and people with weakened immune systems”, especially if it spreads from the intestines to the blood stream.