It forbidden eat yogurt with a meat spoon even not switching it permanently. If you do it one-time thing there is who to rely on.
Explanation:
The Mishna in Chullin (107b) : a person may place meat and cheese in one bag as long as they don’t come to touch. The Gemara asks: And if they touch so what, they are both cold? It answers: Abaye said You are right if they touch, they do not require you to peel off a layer, but they do need to be rinsed off.
The Shulchan Aruch Yod 91:1 writes: Meat and cheese which touched each other are permitted as long you wash the spot where they touched. Is permitted to put them in one bag and we are n to worried they will touch each other.
The Tur quotes the Sefer HaIttur anything which requires one to rinse off if they touch like cold meat and cheese but only cooked meat since you do not rinse it off ever, however something which you usually wash like raw meat it permitted to put it together.
The Baal HaIttur understands the Mishna that anything which needs to be rinsed off if it touches something forbidden to eat together with, it is forbidden to let it touch. The Taz though asks how did the Ittur see it from the Mishna this is exactly what the Mishna tells us: He answer the Mishna is talking about two types of food , Basar and Chalav, are forbidden to touch however a meaty utensil would be permitted to put dairy inside. Therefore, the Ittur said it is also forbidden to put milk in a meat utensil unless you usually wash it off.
The Knesset Hagedolah answers that could have understood from the Mishna that only Basar and chalav we don’t let them touch but non-kosher meat we are not worried you won’t wash it and it is permitted let them touch. Therefore, the Ittur says that even to put in a non-kosher bowl is forbidden since you may forget to wash it off.
The Darkei Moshe asks the Gemara in Pesachim (30b)says that a Kli which we used for Chametz we use it for matzah. It seems y cold food it is permitted to use a no kosher utensil, even without washing it.
He answers three answers:
The Baal Haittur is only discussing foods which are moist but by dry cold foods, like Matzah, its permitted to put it in a Kli which as used ofr cold foods.
There might a difference between Chametz and other prohibitions.
Is forbidden to put cold food in a non-kosher utensil which was used for hot forbidden food, but it was sued only for cold things it is permitted.
So rules the Shulchan Aruch 91:2: Any food which needs to be rinsed like putting meat in a cold non-kosher dish tis forbidden maybe you will eat it without washing it. That is only cooked meat which you do not usually wash off but things which are usually rinsed off like raw meat is permitted. The Rema adds: and only things which are moist but dry foods if the utensil only was sued for cold food tis permitted to put dry food inside without washing it off.
In other words, that food which you usually do not wash is forbidden Lechachilta, to put in a utensil of forbidden food, even if it was used for cold the Rema though is more lenient it is only forbidden if the food is moist but dry foods and the utensil was only used of cold is permitted.
The Rema still understood this is only to do it once in a while but it is forbidden to use it like that on constant basis. As the Rema himself says n YOD 121:5 and in the Mishna Berura OH 451:16.
There is a problem in the Mishna Berura though. In 451:128 he writes that even cold permitted food in a forbidden utensil in only permitted here and there, why should we be so stringent by a utensil which he only used for cold?
In our case though according to the Shulchan Aruch it forbidden to eat a yogurt with a meat spoon even if we only used it or cold meat since we can’t wash yogurt. Even according to the Rema, the yogurt is moist.it is true that the Shach permits even cold food into cold Issur as long as you clean the utensils well. This is based on the Shulchan Aruch in 94:3 which permits putting fruit in in a pot which was cooked Basar BChalav even though the fruit is wet and even though it is not usually washed off. However, he says that is only once in a while but to use them always like that is forbidden since you might use it for hot food once.
According to the Shach it would be permitted to use a meat spoon to eat the yogurt if the spoon was only used for cold stuff. However, according the Shulchan Aruch it would be forbidden. Even though it seems from the Shulchan Aruch in 94 it would be fine the Bach explains that even fruit is only Bdiavad since he has no other way to use that particular li any other way. But he concludes it is a stretch to say that.
