Food poisoning caused by salmonella

Food poisoning caused by salmonella

Food poisoning is a term used when food or water contaminated with germs (microbes), poisons (toxins) or chemicals is eaten or drunk resulting in disease. Microbes include bacteria, viruses and parasites. Food poisoning is also called gastro-enteritis, or simply enteritis.
Salmonella is the name for a group of bacteria that can cause food poisoning. There are over 2500 different strains (sub-types) of salmonella. Salmonella used to be the most common cause of food poisoning in Gibraltar, around the early 2000s the incidence declined sharply following the widespread use of ‘British Lion’ marked eggs.

How does Salmonella spread?

Salmonella bacteria are often found in the intestines of animals. Salmonella can contaminate meat, including poultry (hens, chickens, turkeys etc.), eggs, milk and other dairy products. Potential sources of infection include:

  • Eggs
  • Fruit and vegetables (due to contamination through contact with the manure used for growth)
  • Shellfish (due to contamination from infected sewage in the water)
  • Raw or undercooked meat
  • Milk and dairy products
  • Pets such as tortoises and terrapins; dogs, cats and rodent

Contact with infected animals or their faeces can result in transmission of infection to the human body. It is not advisable to keep reptiles and amphibians, including tortoises and terrapins as pets in a home with children less than one year of age or with anyone who has a weakened immune system.


Symptoms usually appear within 12-72 hours of eating the contaminated food. Typical symptoms are diarrhoea (which can sometimes be bloody) and stomach cramps. The affected individual may also feel nauseous, vomit and can develop a high temperature (fever).

Most infected persons have relatively mild symptoms that improve within 4-7days without any specific treatment.

Sometimes, symptoms can be more severe, especially in young or elderly individuals or if complications occur. If symptoms are severe, it is possible to become dehydrated very quickly.


Mild dehydration is common and is easily and quickly treated by drinking lots of fluids. Severe dehydration can be fatal unless promptly treated because the organs of the body need a certain amount of fluid to work normally. This is especially important if the individual has passed six or more very loose stools (faeces) or vomited three or more times in the preceding 24hours.
Symptoms of dehydration in children include passing little urine, a dry mouth, tongue and lips, fewer tears when crying, sunken eyes, weakness, being irritable or having no energy.

Symptoms of dehydration in adults include tiredness, dizziness or light-headedness, headache, muscular cramps, sunken eyes, passing little urine, a dry mouth and tongue, weakness and becoming irritable.

Dehydration in adults is more likely to occur in:

  • Elderly or frail individuals
  • pregnant women
  • Individuals with severe diarrhoea and vomiting, particularly if they are not able to replace the fluid lost with sufficient drinks

Note: Please consult a doctor quickly if you suspect that you or the affected individual is becoming dehydrated


Symptoms usually settle within a few days. However, in severe cases, the affected individual may need to be hospitalised.


  • Drink plenty fluids. This includes water, light fruit juices and soups
  • If you are experiencing bouts of watery diarrhoea, try and drink at least 200ml after each bout to replace the fluid lost
  • If you are vomiting, try and take small slow sips and persevere
  • Elderly individuals are sometimes prescribed rehydration drinks that are available in most local pharmacies
  • Once you are able to keep fluid and foods in, start with small light meals and avoid fatty, spicy or heavy foods
  • Antidiarrhoeal medication is not usually necessary and it is best to seek advice from your GP
  • Paracetamol and ibuprofen may help to ease high temperature or headache

Note: Do not use antidiarrhoeal medication if you pass blood or mucus with the diarrhoea, if you are pregnant or if you have a high fever

Prevention of Spread

If you are or anyone you are caring for is, infected with salmonella:

  • Wash your hands thoroughly with soap after using the toilet, changing a nappy and before preparing, serving or eating food
  • Wear gloves if handling a potty and make sure to wash it thoroughly with hot water and soap and let it air-dry
  • Do not share towels or flannels. If clothing or bedding is soiled, dispose of any remaining stools (faeces)into the toilet and wash the item in a separate wash at high temperature
  • Use disinfectant to clean the toilet and bathroom regularly and wipe all surfaces including taps and handles, preferably with a disposable cloth
  • Stay away from work, school or college for at least 48hours after the last episode of diarrhoea and/or vomiting
  • Avoid contact with other people as far as possible during this time
  • If you handle food on a regular basis, you must inform your employer if you develop symptoms of vomiting and/or diarrhoea, and immediately leave the food-handling area
  • If you work with vulnerable groups of people such as the elderly, unwell or the young, you should inform your employer if you develop symptoms.

‘4 Cs’ to help prevent food poisoning (Food Standards Agency, UK)

1. Cleanliness

  • Keep work surfaces and utensils clean
  • Wash and dry hands regularly but particularly after using the toilet and , handling raw food and; and before preparing food or touching ‘ready-to eat’ food
  • Do not prepare food if you have diarrhoea or are vomiting
  • Cover any cuts and sores on your hands with a waterproof plaster before you touch food
  • Wash raw fruits and vegetables before eating
  • Change dishcloths and tea towels regularly
  • Wash your hands after touching pets or animals, visiting farms or gardening

2. Cooking

  • Make sure to cook food thoroughly, especially meat in order to kill bacteria
  • If you are reheating food, ensure it is piping hot right through
  • Do not reheat food more than once
  • Do not drink water if you think it is not safe-this includes the use of ice cubes
  • Drink pasteurised or boiled milk and avoid raw eggs

3. Chilling

  • Chill or refrigerate foods as necessary
  • Make sure your fridge temperature is kept between 0°C and 50°C-do not leave the door open unnecessarily
  • Cool left-over food quickly and refrigerate once cool

4. Cross-Contamination

  • Always wash your hands after touching raw foods
  • Separate raw, cooked and ‘ready-to eat’ foods
  • Keep raw meat in a sealable container at the bottom of the fridge
  • Do not use the same knife, surface or chopping board for preparing raw and ‘ready- to- eat’ foods
  • Clean knives and utensils thoroughly after preparing raw foods

For further information, contact the Infection Prevention and Control Department at St Bernard’s Hospital
Telephone: 20072266 Ext 2315