Toxin poisoning is being investigated after 36 cases of children falling ill after drinking baby formula.

An investigation has been launched by the UK Health Security Agency (UKHSA) into children who had consumed suspect batches of formula and developed symptoms consistent with cereulide toxin poisoning. It comes after the Food Standards Agency confirmed last month that Nestlé was undertaking a precautionary product recall of several batches of 12 SMA Infant Formula and Follow-On Formula due to suspicions they may contain cereulide toxin.

The UKHSA said it and partner agencies had received 24 reports in England, seven in Scotland, three in Wales, one in Northern Ireland and one from the Crown Dependencies. Here we investigate what cereulide toxin poisoning is, the symptoms to look out for and why it can be deadly.

Has your child been affected by the recall? Email martin.bagot@mirror.co.uk

• Dozens of babies suffer toxin poisoning symptoms – see all baby formula recalls

What is cereulide?

Cereulide is a toxin produced by certain strains of Bacillus cereus bacteria. Bacillus cereus is a type of bacteria commonly found in the environment, including in soil and dust which can contaminate foods such as rice, pasta and dairy products. Under certain conditions, the bacteria can grow and produce toxins such as cereulide which may cause food-poisoning when consumed.

Cereulide is highly heat-stable, meaning it is unlikely to be deactivated or destroyed by cooking, using boiling water, or when preparing infant formula. Even properly prepared formula can still contain the toxin and cause illness.

What are the symptoms of cereulide toxin poisoning?

Cereulide is a toxin that can cause sudden vomiting, diarrhoea and stomach pain 30 minutes to six hours after ingestion. In younger infants, it can change the body's salt balance and lead to complications such as dehydration.

In infants these symptoms can present as persistent crying and refusal to feed and distress within a few hours of drinking contaminated infant formula. Infants may become lethargic, refuse feeding. Signs of dehydration are little or no urine, no tears when crying, sunken eyes or a sunken soft spot (fontanelle) on the head.

Why is food poisoning dangerous in infants?

In infants their developing immune systems cannot effectively fight bacteria, and their small bodies quickly become severely dehydrated from vomiting or diarrhea. Infections can progress to serious, life-threatening complications such as kidney failure, sepsis, or botulism, within a day or two, leading to muscle paralysis and breathing difficulties.

What to do if symptoms appear?

Symptoms typically develop very rapidly, usually within 30 minutes to six hours after consuming contaminated formula.

Parents should seek immediate medical attention if their infant shows symptoms of persistent vomiting, diarrhoea or distress after consuming infant formula. Experts say parents should not wait to see if symptoms improve, particularly if symptoms are severe.

What is the treatment for and long term consequences of cereulide poisoning?

The only treatments provide support for the infant while it fights the food poisoning. It focuses on managing the symptoms including managing dehydration through fluid replacement, controlling vomiting and diarrhoea, and monitoring by healthcare professionals. Antibiotics do not work.

Most people recover completely from cereulide poisoning without the need for medical treatment. Severe cases are rare but early diagnosis is vital.