Just spotted this recall on the Recalls.gov.au site.
It affects all Blue Ribbon ice cream sold and but doesn't pinpoint when these may have been sold. It only states that products with best before dates between 28 April 2017 to 27 April 2018 may have pieces of plastic.
If you have one of these, take them back to the point of purchase.
I highly recommend subscribing to their RSS or email alerts as there are a good amount of recalls that may affect you.
also: https://itunes.apple.com/au/app/accc-recalls-australia/id468…