Reference for Moed Katan 25:5

אמר אביי נקטינן טימא טהרותיו ומת לא קנסו בנו אחריו מאי טעמא היזק שאינו ניכר לא שמיה היזק לדידיה קנסו רבנן לבריה לא קנסו רבנן:

Said Abaye, We have it on tradition that if a man has defiled his fellow's clean [produce]<span class="x" onmousemove="('comment',' Which had been carefully guarded by the owner from contamination, if the malefactor spitefully threw (for instance) a dead reptile on the heap of washed corn or among the gathered olives or grapes (cf. Lev. XI, 29-34) . Priests' due of these could not be eaten, but might only be burnt as fuel. Pious lay-people would not buy such produce.');">⁹</span> and dies they do not penalize his son after him [to pay for the damage caused]. What is the reason? 'Imperceptible damage<span class="x" onmousemove="('comment',' As there is no visible change in the produce that has been thus deteriorated, he call say that all is still as it was.');">¹⁰</span>

Jastrow