Inactivation of Clostridium sporogenes in Clover Honey by Pulsed UV-light Treatment

Honey has naturally low levels of microorganisms due to its low water content and high concentrationof sugars. However, it has been known to contain the spores of yeast, mold, and bacteria resulting inspoilage of the product. Clostridium botulinum, is associated with honey and is known to cause adisease called botulism. Heat pasteurization, pressure treatment, and irradiation have all been studiedas methods of killing the spores, but have been found lacking. Pulsed Ultraviolet (UV)-LightSterilization is a novel processing method used for microbial inactivation. For the experimentation,spores of C. sporogenes were prepared from cooked meat medium cultures grown in an anaerobic jarfor 7 days at 37oC. Honey was inoculated with 0.1 ml of C. sporogenes spore suspension per 20 ghoney, and mixed well. Pulsed light was applied to the inoculated honey using the SteriPulse XL®3000 Pulsed Light Sterilization System provided by NASA Commercial Food Technology Center.The following parameters were analyzed: 1) the number of pulses 2) the distance between the foodproduct and lamp 3) depth of honey. Treated and untreated (control) honey was analyzed for C.sporogenes. Increasing the number of pulses (or treatment time) also appears to be effective atinactivating the spores. When the depth of honey was decreased from 8 to 2 mm at the 20 cm shelfheight, the spore kill increased for the same number of pulses. Even though varying these threeparameters enhanced the inactivation of C. sporogenes up to 90%, it failed to inactivate the sporescompletely due to insufficient penetration of UV-light into honey.