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Non-Commercial Wild Food in New Zealand

3 The Wild Food Review

Current knowledge and activities

The review set out to ascertain and compile information on current knowledge and activities relating to the harvesting and consumption of wild food in New Zealand in order to better understand and evaluate the risks, and to form a basis for future action.

Current situation

The harvesters and consumers of wild food are a diverse group from a wide range of ethnic backgrounds and cultures. Recreational hunting and fishing, as well as other gathering of wild foods for personal consumption and use, encompasses a range of different motivations including sport, recreation and sustenance. There is also a wide assortment of species of wild food that are harvested, occurring in a diversity of habitats throughout New Zealand.

Under the Animal Products Act 1999, recreational hunters and fishers can kill and process their own animals and recreational catch, or have it done for them by certain identified persons, outside the normal regulatory requirements of the Act, provided that the animal or recreational catch is for their own use or consumption and is not traded.

In spite of the popularity of hunting and fishing as a recreational activity as well as a source of food for subsistence, there is a level of unawareness in the hunting and fishing communities regarding what is safe to eat and what isn’t. There is confusion about safety risks, with both under and over estimation of risk factors.

There is anecdotal evidence that people are either unaware of certain risks associated with the gathering of wild food, or they are ignoring public safety signs advising the presence of toxic material. The Māori Focus Group that was convened as part of the review identified some areas of concern, such as the gathering of puha in known polluted areas, for example near metropolitan areas and on roadsides.

Priorities also differ for people and the strong desire for some foods in certain instances may make food gatherers disregard dangers, such as pollution, or closures that allow stocks to re-grow. The Māori Focus Group also pointed out that, even when signs are put up warning that pollution is present in certain waterways, some people may be so reliant, for example, on shellfish for food that they may be forced (through economic necessity, or lack of awareness) to eat contaminated kaimoana rather than do without it.

An evaluation report of a Pacific Island home food safety radio campaign in 2001 indicated that over half the respondents reported ignoring warning signs about shellfish collection from closed sites¹. The evaluation report further noted that such risk behaviour should be targeted in future campaigns.

ESR literature search report

The chemical and microbial risks that humans are exposed to via wild foods in New Zealand had not previously been comprehensively assessed. A report commissioned by the NZFSA from ESR brought together a significant body of data to show that wild foods in their natural state can be associated with a number of hazards, and may also be associated with hazards that arise from human activity. The ESR report presents information on food/hazard combinations that may pose some risk to human consumption.

While the report indicated that many wild foods can be associated with chemical and microbial hazards, as a whole the information does not lead to the conclusion that wild food presents a major potential for human exposure to foodborne disease in the New Zealand population. However, the report highlighted many data gaps, which prevent an adequate assessment of risk.

The hazards that New Zealanders may be exposed to when consuming wild food will depend on the type of food they are harvesting. For example, animals such as deer and pigs have been associated with several bacteria, parasites and chemical contaminants, and some berries and other plants contain natural toxins that can induce severe illness. The hazards associated with a wild food will also depend on where or when a food is harvested. For example, watercress harvested from streams receiving effluent run-off could carry pathogenic bacteria, and animals harvested during a pest control programme could contain pesticide residues. In certain growth stages some New Zealand plants are highly poisonous.

Based on public health data obtained on incidents and outbreaks of human illness that may have been associated with wild foods (the records are not always clear on the source of the food), ESR reported that Campylobacter and Salmonella were the most frequently identified causative organisms, and were associated with the greatest range of foods. Other organisms of concern, due to their prevalence or severity of illness, were Shiga toxin producing Escherichia coli (STEC), Yersinia, Cryptosporidium and Giardia.

From the data available, it also appears that for some wild foods, heavy metals, anticoagulant vertebrate toxic agents, and polychlorinated biphenyls (PCBs) can exceed the regulatory maximum limits applied to commercial foods. Other than toxins from some marine phytoplankton (the cause of toxic shellfish poisoning, TSP), most of the natural toxins identified by ESR have been associated with foods that are not likely to be consumed in significant amounts. However, ESR found that some toxins pose particularly severe hazards to the consumer and have the potential to cause death. The risks posed by chemical hazards are often difficult to quantify, as health effects may only arise over a long period of low exposure. Public health data does not provide evidence of chronic illness arising from chemical hazards.

Overall, the ESR report concluded that there is a lack of reliable information on wild food harvesting and consumption patterns in New Zealand.

Non-commercial marine biotoxin monitoring programme

NZFSA manages the non-commercial marine biotoxin monitoring programme, along with the commercial shellfish programme. The non-commercial monitoring programme gathers data on shellfish toxicity and phytoplankton so that consumers of non-commercial shellfish can be advised when shellfish in their area is unsafe to collect and eat due to the presence of marine biotoxins. Secondary aspects of the non-commercial programme include undertaking operational studies such as validating test methods, investigating toxicity in multiple shellfish species during toxin events, and data reviews. The programme costs around $1.5 million per annum and is the only area of non-commercial food gathering activity or procurement where NZFSA currently funds specific monitoring activities.

The primary monitoring tool is weekly phytoplankton monitoring in all areas of New Zealand where significant accessible shellfish stocks are found. When pre-set trigger levels are exceeded in water samples shellfish flesh samples are taken and analysed for toxicity. Shellfish flesh samples are also taken routinely in areas where significant recurrent toxicity has been found. Public warnings are generally issued only after toxin levels exceeding the pre-set limits are found in shellfish. The limits are consistent with regulatory limits both in New Zealand and internationally for traded product.

The main priority for the monitoring programme is paralytic shellfish toxins because they are most widespread at high levels and have the potential to be life-threatening based on the levels found and overseas experience. All areas that have recorded above the regulatory levels have weekly flesh samples taken for specific analysis. This includes much of the North Island. Other poisons monitored for, in order of priority, are as follows:

• Amnesic shellfish poison (Domoic acid). This has not resulted in any confirmed illness in New Zealand; however the incident in Canada that led to its discovery did result in several deaths and permanent brain injury amongst some of its victims. It is primarily a problem in scallops in the northern part of New Zealand. Scallops in these areas are tested weekly through the period October to February when levels are likely to be high. Other areas are monitored primarily using phytoplankton. Because the highest concentrations of amnesic shellfish poison are found in the gut and skirt of scallops, the public are advised never to consume these parts of the animal, and monitoring is confined to the adductor muscle and roe portions normally consumed.

• Diarrhoeic shellfish poison (Okadaic acid and its esters). This causes acute diarrhoea and has been found to recur in several South Island areas. A number of confirmed acute illnesses have resulted. These areas have weekly flesh samples taken for specific analysis. Phytoplankton monitoring provides sufficient coverage for the remaining areas of New Zealand as the presence of diarrhoeic shellfish poison correlates well with the presence of toxic phytoplankton species.

• Neurotoxic poison. This was confirmed as present during the initial event that lead to the creation of the biotoxin programme in 1993, however it has not been found since and the causative organism was never conclusively isolated. Shellfish samples are only taken and analysed for neurotoxic shellfish poison in response to high levels of phytoplankton likely to produce toxins, or if environmental indicators show a problem e.g. Respiratory Irritation Syndrome in people.

The ESR report discussed the risks associated with shellfish consumption, and identified norovirus, Salmonella, marine phytoplankton toxins, Hepatitis A virus and Campylobacter as the most important shellfish hazards.

It has been noted that when reports of area closures and illness from eating non-commercial shellfish appear in the New Zealand media, there have been numerous instances of reactions from overseas markets, including temporary bans on the importation of New Zealand commercial shellfish.

Information NZFSA currently offers on wild food

NZFSA currently makes a number of information papers and pamphlets about wild food available to the general public, through its publications programme and through its website (See Appendix 3). The information is primarily directed at those aiming to ‘go commercial’ and become approved suppliers to commercial businesses. However, the publications are relevant to recreational hunters and fishers, although these groups are not specifically targeted.

The residue monitoring programme operating across the commercial animal products industry also acts as a sentinel of wild animal procurement from pesticide-free areas. However, as the programme includes only wild animals processed for commercial trade by two processors located in the South Island, there are some limitations associated with drawing any conclusions about the safety of non-commercially taken wild game throughout New Zealand.

Restricted procurement areas

A restricted procurement area is an area of land from which certified suppliers of wild game can only supply animal meat for trade if it is tested for residues before release to the market. This is because the use of vertebrate toxic agents, such as brodifacoum and 1080, in the area increases the likelihood of contamination of wild game with toxic residues that exceed the maximum residue level (MRL). A restricted procurement area is notified under section 81(2) of the Animal Products Act 1999.

The only current commercial restricted procurement area is in Marlborough. The area was gazetted by Notice issued in August 2004. At this time the restricted procurement notice applies only to pigs killed from the specified area that are sold to game processors. Even though deer may be affected by vertebrate toxic agents, there is no evidence to suggest that high levels of toxic residues are present in deer in this area. The most likely reason for this is that, unlike wild pigs, deer do not scavenge on rats and possums that may have ingested toxic agents.

The publication of a restricted procurement area provides information to recreational hunters and allows them to avoid this area of potential risk if they so wish, or to take other steps to reduce the potential risks e.g. careful identification of target location, hunting only for a trophy, not consuming certain parts of the animal.

Data gaps

The review highlighted that there is a lack of information on the harvesting and consumption of wild food.

Data on harvesting activities

Whilst NZFSA is reasonably confident that it knows the range of wild foods that are harvested, there is a lack of reliable and up to date information on harvesting activities. It is difficult to distinguish the fishing and hunting for sport that exists separately from fishing and hunting for consumption. Fishing, for example, is one of the top five sport and leisure activities for 47% of Māori adults, for 36% of the general New Zealand population and for 36% of Pacific Island adults.²

There is also a lack of reliable data on the quantities of plants, fruits and berries harvested, and the frequency with which each wild food is harvested.

Data on consumption

There is little reliable and up to date information on how much of what is hunted, gathered and harvested is actually consumed. There is a lack of data on the frequency of consumption or the amounts consumed.

According to anecdotal evidence provided by the New Zealand Deerstalkers’ Association (NZDSA), 90% of what is hunted ends up on the table. It would be helpful to have such information substantiated by research to clarify the level of consumption. Anecdotal evidence about deer may not be relevant to other species.

While it is known that hunting, and therefore consumption of game animals, occurs over the whole country, there is limited knowledge of the geographic location of other wild food consumption. Fisheries managers in New Zealand also generally face a paucity of information in respect to recreational fishing.³

National consumption surveys, as they are currently framed, have limited capacity to provide information on non-commercially obtained food that is consumed. The Adult Nutrition Survey, the principal national consumption survey, can not tell us where wild food is sourced from unless a specific question on wild food is included.

Therefore, not enough data is available on the quantities of wild food consumed to accurately conduct an exposure assessment; that is, to assess the level of risk to human health from consuming particular foods based on hazard prevalence data, patterns of harvesting and consumption, and the characteristics of the consuming population.

Relationship between pesticide use patterns and residue profiles

The relationship between pesticide use patterns and residue profiles in wildlife, including wild game meat, is not well tested or documented. We know that brodifacoum lasts many months or even years in animals that have eaten it by scavenging on carcasses of other smaller animals that have been poisoned. There are no known cases of ill health directly linked to humans eating wild animal meat contaminated with brodifacoum. However, brodifacoum residues that have been found in wild pigs that have been presented to the commercial sector (and thus able to be tested) indicate that there may be a potential food safety risk from hunter-gathered/hunter-eaten wild pig in some catchment areas, based on dietary exposure probabilities. Information on exposure and its related risks would be needed so that appropriate mitigation measures, if required, could be identified, and to assist in determining if other research is necessary.

Knowledge of natural toxicants

Not enough is known about natural toxicants occurring in plants, and what effect preparation may have on their safety. ESR found little data on the prevalence of natural toxins, but their report notes that the most severe hazard associated with land plants appears to be natural toxins. Examples of foods associated with natural toxicants that may have health impacts are:

• stinging nettle and a toxin that is a mixture of histamine, acetylocholine and serotonin (5hydroxytryptamine)

• poroporo and glycoalkaloids

• bracken fern and ptaquiloside toxin

• fungi such as field mushrooms and the toxin agaritine.

¹ Fakalago, Paul. [2001] Pacific Island home food safety radio campaign: evaluation report. Auckland District Health Board, Unpublished

² SPARC Facts Series (1997-2001) at http://www.sparc.org.nz/research/sparcfacts - July 2005

³ Williamson, Scott [2000], Ministry of Fisheries, The Economic Value of New Zealand Marine Recreational Fishing and its Use as a Policy Tool