suero

Suero is a Spanish term with several related meanings in biology, medicine and food. In medical contexts, suero refers to serum, the clear yellowish fluid that remains after blood has clotted and the solid elements have been removed. Serum contains most of the blood’s electrolytes, proteins such as albumin and globulins, and antibodies. It differs from plasma in that it lacks fibrinogen and other clotting factors. Serum is obtained by allowing a blood sample to clot and then centrifuging. It is widely used in diagnostic testing and research, including serology and immunology, and is the basis for certain therapeutic preparations such as antisera and immunoglobulin products.

In dairy and food contexts, suero also designates whey, the liquid byproduct obtained during cheese or yogurt production when milk proteins coagulate. Whey contains lactose, whey proteins and minerals. It is processed into various products, including whey protein concentrates and isolates, lactose for food and pharmaceutical use, and liquid whey used as a food ingredient or feed supplement. Whey can be fermented or served as a beverage in some cuisines.

Some Spanish-speaking regions also use suero to mean an intravenous or injectable solution, commonly suero fisiológico, a sterile saline solution (0.9% NaCl) used for hydration, irrigation, and as a vehicle for medicines; it is not serum in the strict sense but is often referred to simply as suero in everyday speech.