Listeria cases in Hawke’s Bay
Hawke’s Bay District Health Board is warning about an outbreak of listeria in Hawke’s Bay.
Four people have been diagnosed with listeria. Two of those, who were elderly and immune compromised, have subsequently died and two have recovered.
Chief executive Kevin Snee said this is tragic for the families involved and the DHB is working closely with the Ministry for Primary Industry (MPI) to establish the source of the outbreak.
Samples of ready-to-eat meats supplied to the hospital have tested positive to listeria. All of the Hospital’s supplied ready-to-eat meat has since been quarantined and the results are now part of an investigation into the source of the outbreak, he said.
Director of Public Health Caroline McElnay said Listeria had a long incubation period of up to several weeks.
Dr McElnay said listeria is very rare and there are only about 25 cases a year in New Zealand it is only dangerous to pregnant women, their babies, the elderly and people with a lowered immune system. Almost all other people are not harmed by it.
The outbreak served as a warning for anyone who was immune compromised, elderly or pregnant to be very aware of food safety. People at high risk should not eat ready to eat foods like soft cheeses made with pasteurised and unpasteurised milk, processed meat and poultry If high risk people develop flu like symptoms such as a mild fever, headache, nausea, vomiting and aches and pains or a mild cough or cold they should seek medical advice
Listeria is a common bacterium (bug) which is widely found in dust, soil, water, plants, sewage and animal droppings.
Hawke’s Bay Hospital is registered under the Food Hygiene Regulations 1974 and operates a food safety programme.
HBDHB MEDIA RELEASE 19 July 2012 ENDS
LISTERIA – Questions and Answers
How did Listeria get into food at the hospital?
The food samples were all pre-packaged ready to eat meat which is supplied to the hospital by an external provider. The Ministry for Primary Industries is making further enquiries.
How does HBDHB ensure food is safe?
- As part of the hospital's food safety programme Nutrition and Food Services only purchases from approved suppliers. For a medium to high risk product like cooked meat, this means that suppliers must have a NZ Food Safety Authority approved food safety or risk management programme in place.
- HBDHB’s kitchen has a Certificate of Registration from Hastings District Council which was achieved with "excellence " from 31/3/2012 until 31/3/2013
- High risk foods are restricted to certain at risk groups e.g. ante natal patients.
Did Listeria cause the deaths of these two people?
It appears that listeria was the cause of death in at least one of these patients and in the other patient it probably was a contributing factor. Both patients were immuno-compromised.
When was the first case of listeria notified?
Most cases of listeria are sporadic, but this number of cases, locally, prompted an intensive search for a possible food source and the Ministry for Primary Industries was informed.
The first case was notified on the 9th May 2012. The second one was the 18th May 2012, the third the 21st June and the fourth the 29th June 2012. These were each fully investigated by the Public Health Unit and no obvious food source found during those investigations.
What action has HBDHB taken?
As part of our investigation the hospital kitchens were inspected and food samples taken. We withdrew all pre-packaged ready-to-eat meats from the kitchen Tuesday 10th July 2012 and reviewed our internal processes. These samples of ready-to-eat meats from the kitchen have now tested positive to listeria. The Ministry for Primary Industries are making further inquiries regarding the source of listeria infection. We are informing the public now in order to raise awareness about the ever present risk of listeria to vulnerable patients
Has anyone else got sick from Listeria and been hospitalised?
No there have been no other hospitalised cases or further notifications in Hawke’s Bay.
What has happened to the food that has tested positive?
We have withdrawn it.
LISTERIA – Fact Sheet
Listeria – What it is
Listeria monocytogenes is a bacteria that can cause a serious illness called listeriosis. It is a common bacterium (bug) which is widely found in dust, soil, water, plants, sewage and animal droppings.
While listeriosis is uncommon and causes few or no symptoms in healthy people, it can be very dangerous for some groups, and these people are much more likely to suffer severe effects of the illness.
Listeria is widely found in nature and it can be transferred through food. Ready-to-eat products, such as deli meats and salads, soft cheeses and foods with a long refrigerated shelf life are often associated with the bacteria. Once food is contaminated with Listeria the bacteria multiply quickly, even at recommended refrigeration temperatures (2-4oC).
People most at risk from Listeria
Although listeriosis is uncommon it can be very dangerous. People more at risk of developing the invasive infection include pregnant women and their unborn children; newborn babies; the frail elderly; anyone whose immune system has been weakened by disease or illness, for example cancer, leukaemia, AIDS, diabetes, liver and kidney disease; and anyone on medication that suppresses the immune system.
Symptoms of Listeria
In people at risk, symptoms may include fever, headache, tiredness, aches and pains. Less common symptoms are diarrhoea, nausea and abdominal cramps. Symptoms may progress to more serious forms of the illness, such as meningitis and blood poisoning. In pregnant women symptoms may be mild, but the consequences can be severe as listeriosis can result in miscarriage, premature birth or, in rare cases, still birth. If you think you might have listeriosis, consult a doctor who can usually diagnose the illness through a blood test.
What are the symptoms of listeriosis in pregnant women?
Listeriosis may cause no symptoms at all or you may feel like you have a mild dose of the flu. Symptoms include: a mild fever, headache, nausea, vomiting and aches and pains in your joints and muscles or a mild cough or cold.
Some women can become very sick with listeriosis and have a very high temperature. This increases the risk of your unborn child being infected.
How are pregnant women infected by Listeria?
Listeria can be transmitted to pregnant women by infected food. The bug has been found in a variety of foods at all stages of preparation, from raw to well cooked left-overs. Listeria will still grow on food which is stored in a fridge.
Listeriosis in New Zealand
In New Zealand around 25 cases occur annually. Of those about 20% are associated with pregnancy or newborn babies. There is more information available from
Precautions for at-risk people
If you or anyone in your household is in a risk group, you can reduce the likelihood of infection by taking certain precautions. Eat only foods that are freshly prepared and well washed, follow good food hygiene practices such as washing and drying hands, and cook foods thoroughly to kill any Listeria bacteria. Refrigerate leftovers immediately and do not keep for more than two days. Reheat to steaming hot (over 70oC) before eating.
How does it affect humans?
Listeria is only dangerous to pregnant women, their babies and people with a lowered immune system. Almost all other people are not seriously harmed by it. If a pregnant woman develops an infection caused by Listeria (listeriosis), it can cause miscarriage and stillbirth. Newborn babies who develop listeriosis can have difficulty breathing; develop a chest infection and an inflammation of the coverings of the brain (meningitis). This can sometimes cause death.
How is listeriosis prevented?
The following foods are safe and nutritious to eat for at risk groups.
• Most foods which have been thoroughly cooked (until piping hot) and eaten straight away.
• Vegetables and fruit which have been well washed.
• All tinned foods.
• Breads and cereals (without added mock creams or custards).
• Dried food (fruit, nuts, lentils, beans etc).
• Pasteurised milk and milk products - yoghurt, cheese etc.
Do not eat the following foods:
• Chilled pre-cooked seafood products, unless eaten hot.
• Pate, pre-cooked chicken, ham and other chilled pre-cooked meat products. Cook any left-over foods or ready-to-eat foods, such as hot dogs, until steaming hot before eating.
• Uncooked seafoods.
• Stored salads and coleslaws, especially from delicatessens or supermarkets.
• Raw (unpasteurised) milk or foods made from raw milk.
Safe ways to handle food at home
- Keep uncooked meats separate from vegetables, and from cooked foods and ready-to-eat foods. Uncooked meats should also be well wrapped or covered.
- Wash hands, knives, and cutting boards thoroughly with hot water and soap after handling uncooked foods.
- Cook left-over foods or ready-to-eat foods, such as hot dogs, until steaming hot before eating.
- Take special care when using a microwave to heat foods all the way through until it is piping hot.
- Wash all fresh food carefully before eating
Higher risk foods -Food type examples
- Cold meats Unpackaged ready-to-eat from delicatessen counters and sandwich bars
- Cold cooked chicken Purchases ready-to-eat
- Salads (fruit and vegetables) Pre-prepared or pre-packaged salads from salad bars and smorgasbords etc
- Chilled fish, shellfish and crustacean Raw (eg. marinated oysters, sashimi or sushi) and smoked ready-to-eat (eg, salmon)
- Cheese Soft unpasteurised (raw milk) cheese (eg, Roquefort)
- Ice cream Soft serve
- Other dairy products Unpasteurised dairy products
Choose safe foods for all at risk groups
Ready-to-eat foods from delicatessens and smorgasbords should be avoided as they may have been prepared some time before being displayed, allowing time for Listeria bacteria to grow on them. Also avoid processed meats and soft cheese unless they have been cooked until steaming hot. If eating take-away food ensure it is steaming hot and freshly prepared.
Safer alternatives to high risk foods - Food type Examples Precautions
- Cold meats Commercially sliced and packed ready-to-eat meat Generally do not eat unless heated until steaming hot*
- Chicken Home cooked Ensure chicken is cooked thoroughly, use immediately. Store leftovers covered in fridge and eat within two days after reheating until steaming hot
- Hot take-away chicken that you selected straight from the cooker Use immediately. Store leftovers in fridge and eat within two days after reheating until steaming hot
- Salads Freshly prepared home-made salads Wash all vegetables and fruit thoroughly before using
- Fish, shellfish and crustacean All freshly cooked fish, shellfish and crustacean Eat while hot
- Cheese Hard cheese Store in fridge
- Soft pasteurised cheese (brie, camembert, blue, ricotta, mozzarella, feta etc) Generally do not eat unless heated until steaming hot*
- Processed cheese, cheese spreads, cream cheese, cottage cheese Buy in sealed packs, eat cold or cooked within two days of opening pack
- Other dairy products Pasteurised dairy products (eg, milk, yoghurt, ready-to-eat custard, diary dessert) Store in fridge and ideally eat within two days of opening
- Packaged frozen ice-cream Choose single serve pots, tubs or slices
- Canned and similarly packaged foods All Store unused portions in fridge in clean, sealed containers and eat within two days of opening
* f these products are purchased in the primary producer’s original packaging, small quantities can be eaten immediately after opening. Do not reseal and eat later, and do not eat if they have been repackaged in a deli or supermarket as they may have been contaminated with pathogens.