Going Kosher – Sharp Foods – Chapter 9

By: Rabbi Amiram Markel

Unique Status of Sharp Foods

Sharp foods have a special status in kosher law unique to them:

a) When they are cut with a meat knife they may not be eaten with dairy (or vice versa), even though both the knife and the food were cold. This is because a sharp food, even when cold, absorbs taste through being cut, even without the medium of heat.[1]

b) Usually, the taste of food absorbed in a vessel is considered to have lost its effect after a period of 24 hours. It therefore loses its original potency to transfer flavor. However, because of their sharpness, the taste transmitted by sharp foods actually enhances the original flavor of the vessel even if it has not been used for over 24 hours. Thus, sharp food “Reawakens” the ability of the vessel to transfer taste, similar to how it was within the 24 hour period.[2]

c) Usually, taste absorbed directly from one food to another is considered to be a primary transference of flavor.[3] However, a taste absorbed from food to a vessel, which is subsequently transferred from the vessel to another food, is considered to be a secondary transference of flavor.[4] Now, if the primary flavor was transferred from a forbidden food to the vessel, the secondary transference of flavor[5] from the vessel to a subsequent food does not lose its original potency; i.e. it remains non-kosher. In other words, any food subsequently cooked in that vessel also becomes forbidden. However, if the primary flavor was transferred from a permitted food to the vessel, the secondary transference of flavor[6] from the vessel to a subsequent food loses its original potency and no longer has the capability of causing the food to become forbidden. Thus, if hot fish was put into a cold, clean meat vessel, it may still be eaten with dairy[7] even if the vessel had been used within the past 24 hour period. Similarly, if lettuce was cut with a clean meat knife, it may still be eaten in a feta cheese salad. However, to the contrary, sharp foods actually enhance the secondary taste of the vessel, thus giving it the ability to transfer taste on the level of a primary flavor.[8] Therefore, if an onion or a radish is cut with a clean meat knife, it may not be added to a feta cheese salad. Furthermore, this is the case even if the knife has not been used during the previous 24 hour period, as indicated in section b) above.

Which Foods are considered Sharp?

 According to most opinions the following foods are defined as sharp:

Garlic, onions, leeks,[9] radish  roots[10] (as opposed to their leafy tops[11]), horseradish,[12] ginger,[13] peppercorn,[14] hot chili peppers, raw uncured olives and sharp cured olives,[15] lemons,[16] limes, citrons,[17] sour apples,[18] sour plums[19] and salted herring, including any heavily salted fish.[20] Some opinions include pickled cucumbers, pickled vegetables and sauerkraut. However, though this opinion is widespread, it is not universal.[21] Inquire of your rabbi for his opinion. Liquids, such as heavily salted brine or strong vinegar[22] and very dry wines[23] are also regarded as being sharp. According to some opinions whiskey is a sharp liquid.[24] However, others differ.[25] Some are of the opinion that virgin olive oil is a sharp liquid, though this too is disputed.[26] Inquire of your rabbi.

Avoiding Problems of Cutting Sharp Food

1) Though it is not a Halachic requirement, as a general rule, it is advisable to purchase knives and cutting boards that will remain pareve and be used for cutting sharp foods, such as onions, garlic and lemons etc. These knives should be stored apart from the meat and dairy utensils and should be washed separately from them, especially if hot water is being used. In doing so the following problems can be completely eliminated:[27]

Common Problems

In Cutting Sharp Food

2) Generally, according to Ashkenazic authorities, if a sharp food was cut with a non-kosher knife it should not be consumed unless the food is sixty times greater than that part of the blade which was inserted into it.[28] According to Sephardic authorities if 2cm/0.8 inch of the food is cut off the food on both sides of the cut, the remaining food may be eaten.[29] However, if it was cut into thin slices or chopped into small pieces none of it may be eaten.[30]

3a) Likewise, according to Ashkenazic authorities, if sharp food was cut with a meat knife it should not be cooked or consumed with dairy, even if the knife was not used within the previous 24 hour period.[31]

3b) According to Sephardic authorities if the knife was not used within the previous 24 hour period, the food may be consumed, as is, with dairy, on condition that the need is great or that by not doing so great loss would be incurred.[32]

3c) If there is not a great need and no great loss would be incurred or the knife had been used within the previous 24 hour period, according to Sephardic authorities 2cm/0.8 inch of the food should be cut off on both sides of the cut, and the remainder may be consumed with dairy.[33] However, as stated above, if it was cut into thin slices or chopped into small pieces none of it may be eaten.[34]

4) As will be explained in the next chapter, as a general rule, a person should wait six hours after consuming meat before eating dairy.[35] This being the case, generally, a person who ate meat should not eat a sharp food that has been cut with a dairy knife until six hours have elapsed[36]. However, there are Halachic authorities that are lenient in this regard,[37] especially if the knife had not been used for more than 24 hours.[38] Inquire of your rabbi for his opinion.

5) On the other hand, a person who ate dairy does not have to wait altogether before eating a sharp food that was cut with a meat knife or cooked in a meat pot. This is because even though sharp food absorbs the meat flavor of the knife or pot, nevertheless, it is not regarded as being actual meat. Therefore, we take the lenient view, that it may be eaten immediately after dairy.[39]

6) If sharp food which was cut with a dairy knife was inadvertently added to a meat dish, it is permitted to consume it on condition that the meat dish is sixty times greater than that part of the blade which cut the sharp food. If it is not sixty times greater, the food may not be eaten.[40] Moreover, the pot containing the food must be rekoshered through immersion in boiling water.[41]

7a) Sharp food which was cut on a dairy cutting board with a pareve knife takes on the status of being dairy and may not be consumed with meat. Likewise, if it is cut on a meat cutting board with a pareve knife it becomes meat and may not be consumed with dairy. This is because when it is cut, it is pushed with pressure against the cutting board. This causes transference of taste from the cutting board to the sharp food.[42]

7b) However, merely placing a sharp food on a dairy cutting board without cutting it does not render it dairy. The same principle applies to placing sharp food on a meat cutting board or a non-kosher cutting board.[43] Nevertheless, if the sharp food is damp or wet, transference of taste occurs, thus causing the food to take on the status of the cutting board or plate it was placed on.[44]

8) Likewise, for the above reason, if sharp food was cut on a dairy cutting board with a meat knife (or vice versa), it may not be consumed. This is because, due to the pressure, the transference of meat taste from the knife combines with the transference of dairy taste from the cutting board, rendering the food non-kosher.

9) If sharp food was cut with a dairy knife (or vice versa) and was then chopped in a blender or food processor, there are conflicting opinions as to whether the blender or food processor became dairy[45] or not.[46] In the event this occurs inquire of a Halachic authority for his opinion.

Cooking Sharp Food

10) Except for hot chili peppers most sharp foods, such as onions and garlic, lose their potency once they become fully cooked or fried. Therefore, from that point on they are treated as any other food would be.[47] However, this only applies if they are chopped with either a dairy or meat knife after being fully cooked in a pareve pan.

11a) On the other hand, if they were cooked or fried in a meat or dairy vessel, they absorbed the meat or dairy flavor and may no longer be eaten with food of the opposite kind. If they are cooked in a meat vessel they may not be eaten with dairy and if they are cooked in a dairy vessel they may not be eaten with meat.[48]

11b) For Ashkenazim they may not be eaten even if the pot had not been used within the previous 24 hour period.[49] However, for Sephardim, if more than 24 hours passed from its previous use, it may be eaten with food of the opposite kind, on condition that when the sharp food was originally cooked in the meat or dairy pot it was not done with the intention of eating it with food of the opposite kind. Even according to Sephardic custom sharp food should not be cooked in a meat or dairy pot with the intention of eating it with food of the opposite kind, even if the pot has not been used within the previous 24 hour period.[50]

12) If sharp food which was cooked in a meat or dairy pot was inadvertently mixed with food of the opposite type it may not be eaten unless there is sixty times more food compared to the walls of the pot that it was cooked in.[51] For Ashkenazim, this rule applies even if the pot had not been used for over 24 hours. For Sephardim, if the pot had not been used for over 24 hours, the food may be eaten.[52]

13) Furthermore, onions sautéed in a dairy pan may not be added to a pareve condiment and then served accompanied with meat.[53]

14) If sharp food, such as onion or garlic, was cooking or frying in a pareve vessel and a meat spoon was inadvertently inserted into it before the onions lost their potency:

a) If there were sixty times more onions compared to that part of the spoon which was inserted into them, the food may be eaten with dairy.

b) However, if there were not sixty times more onions compared to that part of the spoon which was inserted into them, the food may not be eaten with dairy. This is the case even if the spoon had not been used for over 24 hours.[54]

15) If pareve food was cooked in a clean meat pot which had not been used during the previous 24 hour period, and then after being transferred to a pareve vessel, sharp food, such as hot chili pepper, was added and mixed into it, the chili does not affect the status of the food and it may still be served with dairy.[55]