Rav Yochanan of Holleschau claims (recorded here, p26) that this was not the Minhag in Amsterdam, even at the time of the Peri Chadash.
See also here (p. 32) where Rav Yitzchak Yosef quotes Sedei Chemed saying that the Minhag in Amsterdam is to prohibit unsupervised milk.
See this website about milk products in Amsterdam now.