Every Halloween concerned parents make sure their children have received untainted candy, carefully inspecting the candy and making sure the packaging is fully intact. Something rarely addressed however, is how long candy lasts before it goes bad. The facts are actually surprising, and may make Halloween just a little sweeter.
Because candy bars are high in sugar and low in moisture content, they present an inhospitable environment for microbial growth. Pure chocolate can last for two years before any health risks emerge, but after about twelve months it will change texture and become drier and inedible. While the chocolate may last longer, other ingredients within the candy bar, such as nuts, caramel or peanut butter may decay much more quickly. After being packaged just a year, nuts can begin to go rancid, but by the time they produce harmful carcinogens, the candy bar itself will have gotten too decayed to eat.
Sometimes old chocolate bars develop white spots or a dusty quality, this is known as blooming, and has not been proven to harmful to consume. Some have thought that blooming was mold, but in fact it’s bits of fat or sugar that have risen to the surface of the bar due to fluctuations in temperature or changes in humidity. Storing candy in a cool, dry place will prevent blooming from occurring.
Chocolate will only develop dangerous microbe growth if they somehow got inside before packaging. In the past salmonella has been found in chocolate, but under modern manufacturing standards this is much less likely. Overall most candy bars will last far beyond their expiration dates, and many do not even have expiration dates. When food is unsafe it will usually become inedible first, and many expiration dates do not even refer to safety, but more product and brand quality.