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.
Bubonic plague is the most common form of plague. The bacteria that causes the bubonic plague is called Yersinia pestis. This bacteria also causes the other two forms of plague: septicemic plague and pneumonic plague (see Types of Plague).ubonic plague is rarely spread from person to person. Yersinia pestis bacteria begin to multiply once they reach the lymph nodes. (The lymph or lymphatic system is a major component of your body's immune system.