Reduction of Microbial Load on Boneless, Skinless Chicken Breast Using Ultraviolet Radiation
This study examined the effectiveness of UV radiation in reducing numbers of naturally occurring aerobic psychotrophic bacteria, lactic acid bacteria, Campylobacter and surface inoculated E. coli on split, boneless, skinless chicken breasts and the effects the UV treatments had on the taste of the chicken. The objective of the study was to determine the UV dosage that gave the largest amount of microbial kill without adversely affecting the taste of the chicken.
Two groups of 12 breasts were individually vacuum packaged. One group was surface inoculated with 1ml of a 2.0 X 106 CFU/ml culture of generic E. coli. The other group received no inoculation. Two breasts from each group were treated with one of six different UV radiation doses, 0 mW s/cm2 (control-no exposure), 34mW s/cm2, 101mW s/cm2, 202mW s/cm2, 504mW s/cm2 and 1008mW s/cm2. Within 24 hr of the treatments and again after seven days, one breast from each group and each treatment was enumerated for bacterial load. The results showed that bacterial load on the inoculated UV treated breasts were significantly reduced (p <0.05) at every treatment level by an average of 1.5 logs compared to the inoculated controls. There were however, no significant differences (p >0.05) between the inoculated breasts at any of the five different UV treatment dosages. The non-inoculated breasts showed no significant differences in the numbers of bacteria on the controls, as compared to the breasts treated with any of the five UV doses (p >0.05).
Another set of 50 breasts were individually vacuum packaged and divided into six groups. Five groups contained five breasts each. Each group was treated with UV doses of 202mW s/cm2, 504mW s/cm2, 1008mW s/cm2, 2016mW s/cm2 and 3024mW s/cm2 respectively. The control group (n=25) received no exposure. Within 48 hr, and again seven days after treatments, triangle tests for difference were conducted to see if the taste of the chicken had been affected by the treatments. A sensory panel detected a significant taste difference between the untreated chicken and chicken treated at 504mW s/cm2 (p <0.05) two days after treatment, and between the control and chicken treated at 2016mW s/cm2 seven days after treatment (p <0.05).