Question: [Wednesday, 5th Nissan, 5782]
In Chabad we are accustomed to avoid eating processed foods. Does this also apply to dairy, such as milk and cottage cheese and the like which contains certification of being kosher Pesach. It is very difficult for me to avoid eating dairy throughout the entire week of Pesach.
You may choose to eat Kosher for Pesach dairy products if you wish, even if in general you do not eat processed foods during Pesach. Indeed, the Rebbe and other Chabad Rabbeim ate milk and other dairy products on Pesach. Nevertheless, some are particular not to eat dairy products during Pesach due to the fact that they are processed.
There is no officially recorded Chabad custom to avoid eating processed foods during Pesach, and it is simply avoided due to the tradition to avoid relying on the Kashrus of foods of others during Pesach. Nonetheless, certainly one may choose to be lenient regarding certain products which for him are a necessity, such as wine, oil, and milk.
Sources: Regarding the custom of the Chabad Rabbeim: Sefer Haminhagim p. 80 and Sefer Hasichos 5703 regarding the Rebbe Rashab drinking milk; So I Heard from the Rebbe’s secretary, Rav Binyamin Klein and Rav Leibel Groner, that so was the custom of the Rebbe and the Rebbe Rayatz to eat dairy products on Pesach