The Effects of 405-nm Visible Light on the Survival of Campylobacter on Chicken Skin and Stainless Steel

Campylobacter spp. are foodborne pathogens responsible for a significant portion of human cases of bacterial-mediated gastrointestinal disease. A primary method for the introduction of Campylobacter into the food supply is through poultry products. Reducing the number of Campylobacter on poultry products may reduce the incidence of human disease. Research has been conducted on the use of light to inactivate Campylobacter on poultry products and processing environments. More recently, the use of high intensity visible 405-nm light has been proposed for the elimination of pathogenic bacteria. This study investigated the ability of 405-nm light to reduce Campylobacter jejuni and Campylobacter coli in poultry products. Campylobacter in chicken exudate were placed onto chicken skin or food-grade stainless steel before treatment with 405-nm light. A range of 405-nm light doses were applied to cocktails of six C. jejuni or six C. coli strains in exudate at 10 degrees C to minimize thermal effects. Little difference was observed between inactivation of C. jejuni and C. coli on poultry skin with only minor average reductions of 1.7 logs and 2.1 logs, respectively, at the maximal dose of 184-186J/cm(2). More noticeable differences were observed when the samples were placed on stainless steel and treated with a dose of 89J/cm(2), producing an average reduction of 3.0 logs for C. coli but only 1.1 logs for C. jejuni. The maximal dose (181-183J/cm(2)) applied to Campylobacter on stainless steel produced significant (p0.05) reductions for C. jejuni and C. coli of 4.9 logs and 5.1 logs, respectively. However, significant 405-nm-mediated reductions in Campylobacter numbers required exposure times to achieve necessary dose levels that might be impractical under processing conditions. In addition, the most potent exposure times likely produced secondary thermal effects by raising sample surface temperatures above 48 degrees C.