There is a strong minhag cited in the Shulhan Aruch not to eat meat before going to the mikveh. The concern is that meat tends to get stuck between the teeth, which can present a chatzitzah. Some halachic authorities make exceptions for a seudat mitzvah, such as a Shabbat or Yom Tov meal. On the other hand, the halachot of Shabbat may make it harder to clean the teeth well. Common practice is to be lenient with a seudat mitzvah as long as care is taken to clean the teeth well after eating or to keep the teeth clean during the meal.
There is halachic debate as to whether this minhag applies to any meat food, or only to unprocessed meat, since ground meat is less likely to get caught between the teeth. There can be a similar argument regarding poultry versus meat. Rav Yakov Warhaftig, one of Nishmat’s poskim, rules that the minhag does not apply to either poultry or ground meat, since they are less likely to get stuck. Care should nevertheless be taken to avoid getting food stuck between the teeth and the teeth must, as always, be cleaned and checked prior to immersion.
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