Go and read the Shuk Machane Yehuda Kashrut Report on The Yeshiva World website.
Short Version:
- If a store does not have a valid teudah (kashrut certificate), don’t assume that it is kosher.
- If a store says that they are Mehadrin but they can’t prove it with a valid teudah, then they probably are not Mehadrin.
- If a salesperson is wearing a kippah and has peyot, it does not mean that they are kosher.
- If the store has a teudah from a bad certifying authority (like Keter haKashrut, Nachlat Yitzchak, Nezer haHidur, Nezer haKashrut) then it means nothing.
- If the teudah is expired, a photocopy, a letter that is copied, don’t trust it.
- Be vigilant. Insist on seeing the teudah and reading the small print.
Oh, and b’teavon.