An Inangahua dairy farmer whose milk was sabotaged with penicillin earlier this month will still have to pay Westland Milk Products upwards of $7000 for a tanker load of tainted milk that had to be poured down the drain.
Police are investigating the deliberate contamination.
Constable Graham Kimber of Reefton police confirmed today inquiries were focused on a disgruntled farm worker.
The contaminated milk was pumped into a tanker laden with milk from other farms in the area, and then trucked back to the processing factory in Hokitika.
Westland Milk Products chief executive Rod Quin said the tainted milk went into a 12,000-litre tanker, even though the contamination was not his fault.