The actual term Expiration Date refers to the last date a food should be eaten or used. Last means last -- proceed at your own risk. Other, more commonly spotted terms are:  1 Sell by date. 2  The labeling sell by tells the store how long to display the product for sale. 3  You should buy the product before the date expires. 4  This is basically a guide for the retailer, so the store knows when to pull the item.
When an animal or person is infected with Yersinia pestis, the bacteria affect the lymph system, causing the characteristic symptoms. If bubonic plague is left untreated, plague bacteria can quickly multiply in the bloodstream, causing septicemic plague. The bacteria could also progress to the lungs, causing pneumonic plague.
The Black Death began in Europe in 1347 and carried off an estimated 30 percent or more of the population of Europe. For centuries the epidemic continued to strike every 10 years or so, its last major outbreak being the Great Plague of London from 1665 to 1666.he disease is spread by rats and transmitted to people by fleas or, in some cases, directly by breathing. A bubonic plague smear, prepared from a lymph removed from an adenopathic lymph node, or bubo, of a plague patient, demonstrates the presence of the Yersinia pestis bacteria that causes the plague.