That portion of the pad was minced alongside the meat, leading to fragments of plastic contaminating the batch of mince.
The product was later sold to a number of unwitting customers, one of which eventually noticed the plastic and returned to the store to complain.
The supermarket later issued a full recall of the batch, but no other customers returned the mince. It's not known exactly how many individual packets of mince were affected.
Acting for the company, lawyer Iain Thain submitted that the contamination posed very little risk to consumers.
"The foreign matter in the mince was food-grade material, and it was in tiny little pieces because it was minced. It had absolutely no risk of any harm to anybody at any time," Thain said.
"It was human error. The butcher involved had over 25 years of experience - it's just one of those things that unfortunately happened."
Thain also told the court that the supermarket had stopped the practice of mincing unsold meat since the incident.
"This store immediately took action to prevent this ever occurring again. They've removed all soaker pads and they stopped the practice of reworking meat.
Judge Ingram determined that the offending was at the low-end of offences under the Food Act
"This is not a case where there are any prior convictions or where the defendant has ever come to notice before. This is an isolated complaint.
"Having said that, I'm satisfied on the material before me that from time to time, the same thing has happened at other supermarkets. It would be best if the industry found a way to ensure that it can't happen in the future."
The judge sentenced the company to a fine of $7500, minus both a 25 per cent and 15 per cent discount for an early guilty plea and efforts made to prevent the problem from occurring in the future respectively.
In total, the company was fined $4500 and ordered to pay $130 in court costs.
