Fermentation is a metabolic process often associated with the preservation of food or the creation of desirable flavors and textures. It involves the controlled breakdown of organic molecules by specific microorganisms in the absence of oxygen. The question of whether blood can undergo this process has a definitive scientific answer: no, blood does not undergo traditional, controlled fermentation. When blood is exposed to microbial action, its unique chemical makeup ensures the process that takes place is not fermentation, but a destructive form of decomposition known as putrefaction.
The Requirements of True Fermentation
Controlled fermentation, which yields products like yogurt, sauerkraut, or beer, depends on three specific requirements. The first is the presence of a readily available and high concentration of a simple carbohydrate substrate, such as glucose, fructose, or lactose, providing microorganisms a substantial energy source. The second requirement is the use of specific, non-pathogenic microorganisms, such as Saccharomyces yeast or Lactobacillus bacteria, whose enzymatic pathways produce predictable and safe compounds like ethanol or lactic acid. The final requirement is a controlled, typically anaerobic environment where the microorganisms convert the carbohydrate substrate into a stable, often acidic end product. This accumulation of acid or alcohol acts as a natural preservative, distinguishing fermentation from random microbial spoilage.
Analyzing Blood’s Composition as a Substrate
Blood is a complex fluid that fails to meet the basic substrate requirements for controlled fermentation due to its specific composition. While blood plasma contains some glucose, this sugar is quickly metabolized by cells in the body or is present in a relatively low concentration compared to traditional fermentation media. The primary structural components of blood are water (over 90% of the plasma) and complex proteins.
The overwhelming presence of complex proteins, such as albumin, globulins, and iron-rich hemoglobin, dictates the type of microbial breakdown that occurs. Microbes colonizing blood focus primarily on breaking down these large protein molecules for their nitrogen and carbon content. Although bacteria can metabolize the small amount of free glucose, the substrate ratio heavily favors protein decomposition over carbohydrate fermentation.
This high protein concentration, coupled with the presence of iron, steers microbial metabolism away from the acid or alcohol production characteristic of fermentation. The iron within hemoglobin influences the chemical environment and the types of anaerobic bacteria that thrive. Blood’s composition is optimized for a process focused on breaking down peptide bonds rather than simple sugars.
The Actual Microbial Breakdown: Putrefaction and Spoilage
When blood is removed from a living system and exposed to the environment, the microbial process that takes over is putrefaction, a form of spoilage. Putrefaction is defined as the anaerobic decomposition of proteins by bacteria and fungi. This process is largely driven by bacteria that naturally inhabit the gut, such as Clostridium and Proteus species, which proliferate after death or exposure.
These bacteria utilize proteolytic enzymes to break down the complex proteins and amino acids present in the blood. Unlike the desirable products of fermentation, this protein decomposition yields a range of volatile and toxic compounds. These byproducts include foul-smelling amines, such as cadaverine and putrescine, formed from the breakdown of the amino acids lysine and ornithine.
Gases are also significant products, including ammonia, carbon dioxide, and noxious hydrogen sulfide. The production of these compounds makes the resulting substance biologically unsafe and highly odorous. Putrefaction is the body’s natural decay process, driven by the breakdown of its protein-rich components.