2,433. Flavor vs. Physical Presence
Maachalos Assuros 15:2
Pursuant to the previous halacha, if fat from the kidneys falls onto beans and melts into them, the beans should be tasted (by a non-Jew). If he doesn’t taste the fat, the beans are permitted. If not just the taste but also the actual fat is present, then the beans are prohibited under Biblical law; if the fat can be tasted but it has no physical presence, then the beans are prohibited under rabbinic law.
Maachalos Assuros 15:3
An example of physical presence is as follows: let’s say that there was enough fat for an olive-sized volume of it to be in each serving the volume of three eggs. If someone eats such a serving of beans, he’s liable to the penalty of lashes because it includes an olive-sized volume of the forbidden fat. In such a case, there’s not just the flavor of the fat but also a physical presence. If one eats a serving smaller than the volume of three eggs, he’s liable for stripes for acting rebelliously as called for under rabbinic law. Similarly, if there was less than the volume of an olive of fat for each three-egg-sized serving, one isn’t liable to lashes, but rather to stripes for acting rebelliously. This is so even if the flavor of the fat is discernable and one eats the entire pot of food.