Quark (dairy product) these products are obtained by straining yogurt (milk fermented with thermophile bacteria), quark is made from soured milk fermented with mesophile bacteria. Quark is possibly described by Tacitus in his book "Germania" as "lac concretum" ("thick milk"), eaten by Germanic peoples. However, this could also have meant soured milk or any other kind of fresh cheese or fermented milk product. Although quark is sometimes referred to loosely as a type of "cottage cheese", they can be distinguished from the different production aspects and textural quality, with the cottage cheese grains described as more chewy or meaty. The word "Quark" (Late
Quark state to a lower mass state. Because of this, up and down quarks are generally stable and the most common in the universe, whereas strange, charm, bottom, and top quarks can only be produced in high energy collisions (such as those involving cosmic rays and in particle accelerators). For every quark flavor there is a corresponding type of antiparticle, known as an antiquark, that differs from the quark only in that some of its properties (such as the electric charge) have equal magnitude but opposite sign. The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in