The process of decay in the organic matter through microorganisms which results in the production of foul smell is known as Putrefaction. This happens between 10 to 20 days of the death of the organism. A series of events happen during the process of putrefaction such as- Decomposition of proteins, Breakdown of cohesiveness between the tissues and, liquefaction of most organs. When the putrefying bacteria and fungi spread on the body, they decompose the body tissues and organs. They play a major role in recycling nitrogen from dead organisms.

Putrefaction is considered as the fifth stage of death, followed after paleness of the skin (Pallor Mortis) within, change in body temperature (algor mortis), rigidity or swiftness in the movement of a corpse(rigor mortis), settlement of blood on the lower side of the body (livor mortis).

The above-mentioned stages are produced by the release of gases that undergo bacterial reductive catalysis which result in distension of abdomen, swelling of face and genitalia, and purging of putrefactive liquids from mouth and nostrils.

Among the various putrefactive microorganisms, the aerobic bacteria Bacillus and Pseudomonas are prevalent. The mold fungi are also involved in putrefaction but do not play a major role in the process.

Process of Putrefaction

The process of putrefaction involves different stages: In general, all the organic tissues contain chemical energy, and, when it is not maintained the tissue begins to hydrolyze due to the reaction of water into amino acids. Initially, the anaerobic bacteria in the digestive tract of humans start to digest the proteins of the body, this makes the tissues weak. Next, the proteins breakdown where the bacteria release certain gases and organic compounds like putrescine, and cadaverine, emitting a foul smell like rotten flesh. The bacteria traverse throughout the body by using the blood vessels.

During the process of putrefaction, the skin tissues of the body rupture and release the bacterial gas. Finally, the body reaches the stage of skeletonization.

Factors Affecting Putrefaction

Two kinds of factors can be observed which affect the putrefaction:

  1. External Factors

  2. Internal Factors

External Factors:

  • Environment: A rise in temperature increases the level of putrefaction. The optimum temperature to be maintained during the process of putrefaction is 21°C to 38°C. Putrefaction process hinders if the temperature is below 0°C or above 48°C.

  • Moisture: Lack of air or if a body is immersed in water the putrefaction process slows down. Microbes are formed in the presence of moisture and air resulting in degradation of the organism.

  • Clothing: Clothes fitting exactly to the body reduce the blood flow, making it difficult for the bacteria to sustain for putrefaction. Loose-fitting clothes have an uninterrupted blow and moisture flow which is perfect for putrefaction.

  • Light: The presence of light inhibits the putrefaction process as the microorganisms are active during darkness.

Internal Factors:

  • Age: Body of a young person undergoes putrefaction at a rapid speed when compared to an older person. On the other hand, the bodies of infants and fetuses undergo putrefaction slowly as they are sterile.

  • Body Condition: Due to the presence of more heat and fluids in the tissues, a fat body putrefies quickly than a lean body.

  • Cause of Death: People who die with infectious diseases undergo putrefaction process quickly when compared with people who died due to accidents.

  • External Injuries: Putrefaction process is done easily on bodies which have injuries as they have the bacterial invasions.

The putrefaction rate is higher in the air when compared to soil, earth, and water. Body discoloration happens within 12-24 hours when exposed to air.  The putrefaction can be delayed using carbolic acid, arsenic strychnine, and zinc chloride. This delay is usually done for funeral and medical or religious practices.

Putrefying Bacteria

The bacteria which are involved in the putrefaction of living organisms are known as putrefying bacteria. Putrefying Bacteria utilize amino acids or urea which decompose dead organisms. During this process, ammonium ions are produced, which later are converted into nitrate. Finally, these can be used by plants for producing more proteins. The putrefying bacteria are also involved in human digestion present in the gastrointestinal tract. Fermented milk contains lactose which is used by the bacteria for improving digestion.

The first body part which starts to decompose is the brain as it immediately loses cells after death. Apart from this, organs with huge bacterial cells tend to decompose faster such as the stomach and intestines. When compared with the organ containing maximum fluid and the organ with most bacteria, the decomposition rate is higher on the organ with most liquids which is the brain.

On the other hand, the last organ to decompose is kidneys. This organ remains viable for 36-48 hours after death.

Adipocere Formation

A modification in the process of putrefaction through hydrolysis and hydrogenation of fatty tissues to a yellowish, greasy, rancid, wax-like substance called adipocere. This adipocere is initially yellow and soft, after a few months, it turns white and brittle. After a while, it becomes tough to retain the facial structure as it becomes unrecognizable.

FAQ (Frequently Asked Questions)

1. What causes Putrefaction ?

The decomposition of organic matter with the intervention of bacterial or fungal digestion along with the release of gases that infiltrate the body’s tissues, resulting in deterioration of tissues and organs is the main reason for putrefaction. The duration of putrefaction depends on the viability of the organs and the condition during the time of death. Various external atmospheric factors and internal body factors play a vital role in determining the duration of putrefaction. This is the final stage of death.

2 .What is the initial or most common sign of putrefaction?

The foremost sign of putrefaction is greenish discoloration of skin near the region of skin. This appears within 12-24 hours after death. The internal sign shows a discoloration underneath the surface of the liver. These physical changes occur due to the physicochemical and environmental processes. The greenish coloration starts from the region around caecum, then passes to the abdomen, and finally moves to the entire body. This green color is due to the reaction of hydrogen sulphide released by bacteria with hemoglobin which forms sulfa haemoglobin. This discoloration is visible through the skin which is also called ‘marbling’ of skin.