Many consumers have experienced a strange metallic taste starting one day after eating pine nuts. In order to find out what causes this taste the Swedish Food Administration (NFA) has analysed pine nuts from six different packages, supplied by persons afflicted by the taste phenomenon. No significant differences in the content of pesticides or mycotoxines compared to nuts without the metallic taste were found.
In January 2010, on the NFA website, the Swedish Food Administration informed the consumers about the ”problem” with some pine nuts. We also asked consumers that had been afflicted by the taste to write to us in order to clarify if they experienced any sustained health effects.
More than 300 consumers wrote, and from the answers the following conclusions were drawn:
- Only one or two nuts with strange taste seem to have appeared per package, since more than one person seldom was afflicted by the taste (although several persons ate nuts from the same package).
- In some cases persons, not related to each other, eating nuts from the same package had the same experience of a strange taste; in other cases one person feels the metallic taste in only one nut from the package and not in others. This indicates that the taste phenomenon is not coupled to certain individuals having the possibility to experience the taste, i.e. it is not genetically determined.
- The taste mostly sustained for 4-7 days.
- The origin of the nuts was mostly China (like most pine nuts imported to Sweden).
- The packages with reported ”contaminated” nuts on the Swedish market represented at least 15 different brands.
The Swedish National Food Administration has analysed the samples for content of mycotoxin. No detectable amounts were found. Furthermore, the samples were analysed to determine residues of the 320 pesticides in the NFA control program routine screen. The sample preparation included extraction using the QuEChERS method [1] (extraction with acetonitrile) followed by analysis using LC-MSMS or GC-MSMS in multiple reaction monitoring mode (MRM). None of the 320 pesticides were detected in the nut samples.
For the analysis of mycotoxins, a LC-MSMS method covering 30 commonly occuring mycotoxins was used. None of the mykotoxins were detected in the samples. But, no definite conclusions can be made from the analyses as each pine nut package most likely has contained only a few ”affected” nuts, which furthermore may very well already have been eaten before the analyses were made.
[1] Anastassiades, S.J. Lehotay, D. Stajnbaher and F.J. Schenck, J AOAC Int 86 (2003) 412.