The elderly, pregnant women and people with compromised immunity are being warned over food safety after one person died and two others were hospitalised with listeria infections in Tauranga.
The outbreak has sparked an investigation with one top health official saying it was believed the three people developed their infections in the community before they were admitted to Tauranga Hospital.
They were aged between 70 and 90 and the person who died was terminally ill.
Listeria symptoms vary but can include fever, headaches, tiredness, aches and pains, diarrhoea, nausea or stomach cramps. Symptoms can occur anywhere between three and 70 days of eating contaminated food.
Late yesterday, Geraldine business Talbot Forest Cheese recalled a range of products because of a potential risk of contamination with listeria. There was no evidence at this stage of a link between its products and the Tauranga cases.
Toi Te Ora medical officer of health Neil de Wet said the extent to which listeria contributed to the person's death in Tauranga was unclear.
"Two, including the person who has died, had listeria diagnosed on samples taken on admission and one was diagnosed a week after admission," de Wet said.
"One person has been discharged from hospital."
July 12 was when the first person was diagnosed, de Wet said, while the second and third were diagnosed on July 20.
''The median incubation period is about three weeks and so the infections were most likely acquired in the community in the weeks prior to admission.''
Before these cases, the most recent reported diagnosis was on January 28 this year.
An investigation with the Ministry for Primary Industries was underway to find the source.
MPI compliance director Gary Orr said investigators would look to see if there was a common food connection.
"Any case of listeria is a worry for us, particularly if there is a link to food ... If it is shown to have a link to food then we will move very quickly to take that risk food out of the system or alert the public," he said.
Public health officers would interview the patients or their families about where they had been and what they had eaten to see if there was a link.
The outbreak has prompted a warning to pregnant women and others at risk while authorities are urgently trying to find the source of the dangerous bacteria which can be found in raw fish, processed meat, hummus and many other cold foods.
It is dangerous for newborn or unborn babies, the elderly or people with poor immunity.
De Wet said he was not aware of other possible cases in the area.
Meanwhile, the Talbot Forest Cheese products affected are being removed from shelves and should not be eaten. If you have any of the products listed below in your fridge you should return them to the retailer or throw them out.
*Talbot Forest Cheese
*Bouton D'Or (Goodman Fielder) – Plain Haloumi
*Ornelle (Goodman Fielder) – Parmesan (powdered and block); Haloumi
*Puhoi (Goodman Fielder)
*Cuisine Canteen (FoodHQ) – Basil Haloumi; Chilli Haloumi
*Gibbston Valley Cheese
*Imperial Foods – Diced Feta; Haloumi
*Pams Finest (Foodstuffs Own Brands Limited) – Plain Haloumi
*Griffith's – FetaI
In 2017, All LeaderBrand salads recalled its products after the food-borne bacteria was found in the Caesar salad.
Countdown, New World and Pak'n Save in Tauranga stocked the salads, which were also distributed to Pita Pit and Subway outlets.
The food chains told the Bay of Plenty Times Weekend this week there were "robust" food safety procedures in place.
New Zealand College of Midwives Bay of Plenty and Tairawhiti regional chairwoman Kelly Pidgeon said the disease was a serious issue for midwives, and she stressed the importance of booking a midwife early.
"Women are immunocompromised when they are pregnant so they become at risk, they're immune system won't necessarily deal with it in the same way you would as a non-pregnant person."
If there are even mild symptoms, Pidgeon said it posed a risk for miscarriage.
What people don't know, they don't know, she said but accessing information early was a pregnant woman's best bet.
Tauranga Age Concern general manager Tanya Smith said elderly people should not hesitate to seek medical advice if they had concerns about possible symptoms.
"Don't think it's just a tummy bug."
Professor Steve Flint, an expert in food safety and microbiology at Massey University, told the Bay of Plenty Times Weekend listeria was "one of the most common food poisoning organisms".
"It's reasonably serious for people who are susceptible such as the elderly and infants."
He said the bacteria could be found in "almost any type of food ... all over the world" and grew at low temperatures.
"Every organisation does its best to avoid it."
Outbreaks internationally had involved lettuces, rockmelon and unpasteurised milk in recent years, he said.
"Most of these foods you would refrigerate but if they [listeria bacteria] are present they will grow at refrigeration temperatures which is a bit nasty.
"So it is pretty hardy and it is one of the organisms that the food industry watches very carefully."
Flint said "it really is difficult" to determine the source of contamination, which was often "a big problem".
"When somebody gets sick you want to know what they've eaten but the food they ate is probably discarded so it's hard to get back to the products and test."
People who are in an at-risk group should avoid these certain foods:
• Uncooked, smoked or ready-to-eat fish or seafood, including oysters, prawns, sashimi or sushi.
• Paté, hummus and tahini-based dips and spreads.
• Cold pre-cooked chicken.
• Processed meats including ham and all other chilled pre-cooked meat products including chicken, salami and other fermented or dried sausages.
• Pre-prepared, pre-packaged or stored salads (including fruit salads) and coleslaw
raw (unpasteurised) milk and any food that contains unpasteurised milk.
• Soft-serve ice creams.
• Soft, semi-soft or surface-ripened soft cheese (for example, brie, camembert, feta, ricotta, roquefort).
If you or anyone in your household is in an at-risk group, it is especially important to take a few simple food safety precautions:
• Avoid eating the high-risk foods listed above.
• Follow good food hygiene practices, such as washing and drying hands before preparing food and after handling or preparing raw foods.
• Eat freshly cooked or freshly prepared foods.
• Wash all raw fruit and vegetables very well before eating.
• Cook foods thoroughly.
• Refrigerate leftovers immediately and do not keep for more than 2 days. Reheat to steaming hot before eating.
Source: Ministry of Health
Listeria symptoms may include:
• Aches and pains
• Stomach cramps
- After eating contaminated food, on average, symptoms appear after about three weeks but can occur from three to 70 days.