The Prophet Muhammad ﷺ said: "Cover the vessels and tie the water skins, for in the year there is a night when a plague descends, and it does not pass by an uncovered vessel or an untied water skin without entering it." (Narrated by Muslim, no. 2012, from Jabir).
This hadith, narrated by Jabir ibn Abdullah, recommends covering vessels containing food and drink. Modern science has confirmed the crucial importance of this practice in preventing infectious diseases.
Food and drink left uncovered are exposed to contamination from many vectors: insects (flies, cockroaches, ants), rodents, dust, and airborne microorganisms. Flies, in particular, can carry more than 100 species of pathogenic bacteria, including Salmonella, Escherichia coli, and agents of gastroenteritis.
The World Health Organization (WHO), in its "Five Keys to Safer Food," recommends protecting food from insects, rodents, and other animals, and covering food to avoid any contamination. This recommendation, formulated by modern science, exactly matches the practice taught by the Prophet ﷺ fourteen centuries ago.
The convergence here is solid but general: it is a universal principle of food hygiene, whose wisdom is today fully confirmed by modern epidemiology and microbiology.