I should add that the sources I presented in defense of R’ Abadi’s views are not heterim I personally allow in our home. As the article I paraphrased from Kashrut Authority Australia points out, the position that is taken in other countries with kashrut lists is not something we should avail ourselves of in America, since we have the most exhaustive kosher food available outside of Israel.
That being said, since cheese is often difficult to procure outside of major Jewish areas with a strict hechsher, the mozzarella issue ought to be probed further. However, we’re fortunate that the Polly-O company has gone under the OU. Cabot and all the brands with the Luhot is another matter entirely.