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Pine nuts and pine mouth

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Background: what is "pine mouth"?

Eating pine nuts can occasionally cause some people to experience a bitter or metallic taste lasting from a few days up to 2 weeks.

This taste disturbance has been referred to as ‘pine mouth’ or ‘pine nut syndrome’.

Not all people who consume pine nuts become afflicted with the taste disturbance. The pine nuts do not taste any different at the time, but after 1 to 3 days the bitter or metallic taste becomes apparent and is exacerbated by the consumption of food and drink.

The symptoms normally disappear after several days and there are no adverse health effects.

Latest research, response

Cases of pine mouth are not common, however since 2009 there appears to have been a rise in numbers internationally with several hundred complaints lodged with agencies across countries including France, the UK and USA.

In contrast, the number of reported cases in Australia has been very small.

Identification of any implicated pine nut species is made difficult by the common practice of mixing different species for retail sale.

The cause of pine mouth has not been determined, but several researchers have indicated that a particular species and source of pine nut, Pinus armandii exported from the Shaanxi and Shanxi regions of China, may be responsible for causing the symptoms. This species of pine nut was previously only consumed locally and not widely exported for consumption as whole nuts.

In response to the increased number of pine mouth cases, the Chinese authorities have implemented measures to accredit exporters of pine nuts and implement strict control measures to ensure Pinus armandii are no longer exported. In addition, the international standards setting body Codex Alimentarius Commission has moved to exclude Pinus armandii as well as another species of pine nut Pinus massoniana from its list of edible tree nuts.

The NSW Food Authority has prepared an issues paper to summarise case reports and the most recent research into possible causes of the pine mouth taste disturbance, on behalf of the Implementation Sub-committee (ISC) for the Coordinated Food Survey Plan.

Table of contents
Executive summary
- First reported cases of pine mouth
- Symptoms
- Increasing reports internationally
Pine nut production
- Edible species of pine nuts
- Non-edible species of pine nuts
- Pine nut oil and by-products
Reports of pine mouth
- Reports of pine mouth in Australia
- International reports
- Reports of pine mouth in the media and social media
Research into causes of pine mouth
- Pine nuts responsible for causing pine mouth
- Methods of analysis for pine nut speciation
- Proposed mechanism of pine mouth
Action to date
- European commission
- Codex Alimentarius Commission
- Measures implemented by businesses importing and selling pine nuts
- Industry measures implemented by Chinese exporters
- Recommendations

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