Seven people, including an executive of New Zealand dairy cooperative Fonterra, have been charged with conspiracy to defraud over an illegal milk powder export scam.

The charges result from an 18-month long investigation by New Zealand’s Serious Fraud Office into the alleged illegal export of NZ$50m (US$33m) of milk powder, reported the New Zealand Press Association. The investigation related to allegations in 2001 by the then Dairy Board that milk powder had been exported overseas without being exported through the board, which had an export monopoly.

The Dairy Board later became part of New Zealand dairy giant Fonterra, which carried out its own investigation and found there had been breaches of export rules in 2000 and 2001, but said it had found no evidence of improper personal gain, the NZPA reported.

Fonterra has said only one of the seven people charged was currently working for Fonterra, and that person has now been suspended without pay.