Reference for Bava Metzia 105:2
מאי מה שאין כן במעשר לאו מכלל דמעשר בטיל ברובא ואם איתא דחזקיה הוה ליה דבר שיש לו מתירין וכל דבר שיש לו מתירין אפי' באלף לא בטיל
and require washing of the hands<span class="x" onmousemove="('comment',' That is in respect of fruit. One's hands are normally said to be unclean with what is known as the second degree of uncleanliness — a low degree. This is insufficient to render the fruit of hullin or tithes unclean, and therefore these may be eaten with unwashed hands. But a stricter purity was demanded of terumah and first fruits; consequently it was enacted that the touch of ritually unclean hands imposes upon them third degree uncleanliness; therefore the hands must be washed before partaking of them. — This impurity is only Rabbinical, and therefore the washing of the hands alone was sufficient: for Biblical uncleanliness the immersion of the whole body in a ritual bath (mikweh) was necessary. ');"><sup>4</sup></span> and the setting of the sun.<span class="x" onmousemove="('comment',' If a priest became Biblically unclean, he required Immersion (v. n. 6) and then had to wait until sunset before he might eat of terumah or the first fruits (Lev. XXII, 7). ');"><sup>5</sup></span> These provisions hold good of <i>terumah</i> and first fruits, which is not so in the case of [second] tithes.<span class="x" onmousemove="('comment',' (i) The (second) tithe may be eaten by a zar — consequently, of course, no penalty is involved therein; (ii) it is not the priest's property, as explained in n. 4., but sacred property given to the priests; hence it cannot be employed as kiddushin. — This is R. Meir's view (Kid. 52b); (iii) it does not require a hundred times its own quantity for neutralisation; (iv) the fruit may be eaten with unwashed hands; (v) when one becomes Biblically unclean, he may eat thereof immediately after immersion, without waiting for sunset (v. Hal. I, 9). ');"><sup>6</sup></span>