Marzipan Santas, elves and stollen: Real deal or cheap fakes?

Ilka Haase and colleagues explain that marzipan is a popular treat in some countries, especially at Christmas and New Year's, when displays of marzipan sculpted into fruit, Santa and tree shapes pop up in stores. And cakes like marzipan stollen (a rich combo of raisins, nuts and cherries with a marzipan filling) are a holiday tradition. But the cost of almonds leads some unscrupulous manufacturers to use cheap substitutes like ground-up peach seeds, soybeans or peas.

Current methods for detecting that trickery have drawbacks, allowing counterfeit marzipan to slip onto the market to unsuspecting consumers. To improve the detection of contaminants in marzipan, the researchers became food detectives and adapted a method called the polymerase chain reaction (PCR) -- the same test famed for use in crime scene investigations.

They tested various marzipan concoctions with different amounts of apricot seeds, peach seeds, peas, beans, soy, lupine, chickpeas, cashews and pistachios. PCR enabled them to easily finger the doctored pastes. They could even detect small amounts -- as little as 0.1% -- of an almond substitute. The researchers say that the PCR method could serve as a perfect tool for the routine screening of marzipan pastes for small amounts of contaminants.