Francesco Redi, an Italian physician, took the flesh and cooked it so that no organisms were left alive. Then he placed flesh in three jars, of which, one was uncovered, the second was covered with parchment and the third one was covered with fine muslin. He kept these jar for a few days and observed that maggots developed only in the uncovered jar through the flies also visited other jars.
So, the correct answer is 'Meat was not spoiled, when heated and kept sealed in a vessel'.