What is the main indicator of putrefaction in a decaying body?

The main indicator of putrefaction in a decaying body is the darkening of skin in suspended body parts. This darkening occurs due to the breakdown of hemoglobin and the accumulation of certain gases produced by bacteria during the decomposition process. As the body decomposes, the processes result in changes to the pigmentation of the skin, making it appear darker in areas that may be affected more directly by the bacterial activity.

In the context of decomposition, lividity refers to the pooling of blood in certain body parts after death, which is not a specific indicator of putrefaction itself. The stiffening of muscles, known as rigor mortis, and the reduction of body temperature, or algor mortis, are additional post-mortem changes that occur but do not directly identify the stage or indicators of putrefaction. While these processes may occur simultaneously, the darkening of the skin is more specifically linked to the advancement of decomposition and the effects of bacteria breaking down tissues.