Nineteen people have been arrested for attempting to sell green olives treated with copper sulphate to brighten their color, the Guardian reports. Italian police seized 85,000 metric tons of the tainted olives, as well as thousands of metric tons of foreign olive oil being passed off as "Made in Italy."
Counterfeiters treat the olives, which are recycled from previous years' harvests, to dupe consumers into thinking they're fresh. Overexposure to copper sulphate, which is normally used in pesticides, can cause nausea, vomiting, abdominal pain, and death in some cases. Italian police reportedly believe the substance was used because it isn't classified as a colorant, so authorities don't typically test for it.
Authorities estimate the black market for counterfeit food items in Italy is worth about $1.1 billion per year.
The wine industry is one of the biggest targets of counterfeiters. Earlier this week, Italian police seized $400,000 worth of fake Moët champagne.