Important posting by the administrator (Yankel Wajsbort) of the Ask Kosher Australia Facebook group…
We do not recommend this rennet set cheese. Please see here for a discussion about how to make cheese kosher https://oukosher.org/blog/consumer-kosher/kosher-cheese/.
Coon & King Island cheeses are made by Lion Dairy – a non-Jewish company – and these mass-produced cheeses would be considered Gevinas Akum. The question is how “It’s Kosher” (the supervising Rabbi) makes these Coon & King Island cheeses Gevinas Yisrael. Normally, non-Jewish cheese companies schedule a special supervised run for kosher cheese with kosher symbol on the label. A mashgiach/Rabbi is present in the factory who will add the kosher rennet to the milk for each kosher batch (this is the opinion of the Shach, as explained in the OU document). We believe that Coon & King Island are made in different factories.
Happy to provide you some information how mass produced yellow rennet set cheese is made. These companies usually manufacture cheese 24 hours a day. Milk is pasteurised and cooled to the right temperature and fed into the cheese vats (at least 8). The cheese vats for cheddar and tasty style cheese (made by large dairy companies) have typically a capacity of 14,000 litres each. By the time that the eighth vat is full, the first one has been emptied, washed and is ready to fill again. Every time the mashgiach would need to add rennet to the milk in each cheese vat order to make all the cheese kosher. Curds from the cheese vats are combined and further processed on the continuous line into large blocks of cheese. Large blocks of cheese are then matured for a couple of months and finally sliced, cut, shredded, packed and labelled, possible in a different location than the cheese making and/or maturing.
We suggest you ask the agency to explain, when and who they sent as a mashgiach to the factories to add the rennet, in order to consider all these cheeses Gevinas Yisrael and kosher.