chapter  18
Ultraviolet Light and Food Preservation
WithAurelio Lo´pez-Malo and Enrique Palou
Pages 18

Food processing and preservation technologies must maintain the fresh-like characteristics of foods, while providing acceptable and convenient shelf life, as well as ensuring safety and nutritional value. Nonthermal processes that are applied to food preservation without the collateral effects of heat treatments are being intensely studied and tested. One such procedure is the irradiation of foods with short-wave ultraviolet (UVC) light. Short-wave ultraviolet light is reported to be an effective method for inactivating bacteria that contaminate water and the surfaces of several materials. Ultraviolet (UV) technology has been known for over 60 years, but commercial equipment was primarily manufactured for pharmaceutical and aquaculture industries, which could not tolerate chemical disinfecting. In the past two decades, food and beverage industries and UV equipment manufacturers have looked upon each other with an opportunistic eye. The lethal effects of UVC and its effectiveness as a disinfectant are well known. However, the microbial response within foods to this emerging technology has just recently been investigated. Irradiation of surfaces and treatment of fruit and vegetable juices with UVC have drastically reduced microbial counts, especially when using recirculation at selected flow rates. Statistical analysis demonstrated the nonsignificant effect ( p > 0.05) of UVC on fruit and vegetable juice color and overall acceptability when compared to their fresh counterparts. Short-wave-ultraviolet processes when applied to heat-sensitive fruit and vegetable juices are an interesting preservation alternative, because important microbial reductions are generated without any meaningful sensory changes, while providing an acceptable shelf life.