Clove has been used for centuries as a primary preservative as well as a flavoring agent for preserved foods. Before modern technology like refrigerators and stoves was available to prolong the life of food or preserve it through canning, most people relied on curing, smoking, pickling, and salting to make sure that their food would last during poor weather. Preserving food makes it inhospitable to microbes and effectively halts the rotting process. Cloves, which are the aromatic buds of a tree native to Indonesia, are high in antimicrobial, antifungal, antioxidant, and antilarval properties. The primary substance in cloves that makes it so great for preserving food is called eugenol. Because of its antimicrobial properties, in addition to its strong fragrance, eugenol may also be used in cosmetics as a preservative.
As a primary preservative of foods, meat may be packed in clove buds to prevent bacterial growth and decay of the tissue. In the Medieval period, meats were often rubbed with or packed in barrels of salt and spices (including clove) to prolong their shelf life and impart flavor.
Many people today who preserve foods by canning include clove bud in their recipes, though I think these people do so more for the flavor than any antimicrobial concerns.