The onset of putrefaction is the process by which organic matter begins to decompose after death. This process is primarily caused by the action of bacteria and enzymes that break down tissues, leading to the release of gases and foul odors. Factors such as temperature, moisture, and the presence of oxygen can influence the rate of putrefaction. During putrefaction, the body undergoes several stages, starting with autolysis, where cells break down due to the release of enzymes. This is followed by the activity of bacteria, which further accelerates decomposition. The entire process is a natural part of the ecosystem, recycling nutrients back into the environment.