Sharp objects were found in strawberries in the Adelaide suburb of Salisbury and in South Australia's Clare Valley yesterday.

Police say no-one was injured and there was no information to suggest the incidents were linked.

They advised people to cut strawberries up prior to consumption.

SA Health has been informed about the reports.

Premier Steven Marshall said he was disappointed there had been more cases of contamination, just as South Australia's strawberry-picking season began.

"Let's not give in to these cowards who are out there trying to undermine the strawberry production in South Australia, so my advice is go out, buy strawberries, be careful, but support South Australian farmers and growers," he said.

More than 100 incidents of needles were reported around Australia in September, as well as an isolated case in New Zealand.

Strawberries were recalled from supermarket shelves and many farmers were forced to throw away their crops.

A police investigation has so far produced no breakthroughs.

An Adelaide man has been charged with falsely claiming there was a needle in strawberries he bought from a suburban supermarket.

He told the Adelaide Magistrates Court last month that he intended to plead not guilty to the crime.