In the U.S., water immersion chilling (WC) is commonly used to chill poultry while other regions of the world, such as the European Union (E.U.), prefer air chilling (AC). Water chilling is accomplished by submerging eviscerated carcasses in chilled water, while air chilling utilizes forced air in a cool room to chill carcasses. Water chilling is typically faster than traditional AC and antimicrobials can be incorporated directly into the water. But concerns over retained water on carcass, cross-contamination and wastewater disposal exist. Air chilling also comes with concerns over decreased yield because of evaporative loss as well as other concerns such as surface drying. A potential benefit of AC, however, would be an increase in the U.S. poultry export market. The E.U. currently bans U.S. poultry over concerns about the addition of chlorine to water during chilling. The U.S. is currently the largest poultry producer in the world and the second-largest exporter. As demand for poultry continues to rise, poultry products with longer shelf life and less food waste will be needed. Meanwhile, widespread efforts to reduce natural resource and energy expenditures, such as water, as a means of enhancing sustainability, exist across the meat industry, including the poultry industry. Therefore, the objective of this study was to compare the impact of WC and AC on the shelf life and meat quality of bone-in and boneless chicken breast.
A total of 256 eviscerated non-chilled chicken carcasses were obtained from a commercial processing facility in California and transported to the UC-Davis meat laboratory within two hours. Carcasses were randomly and evenly assigned to either WC or AC, then were evenly assigned to be fabricated into bone-in (BI) or boneless (BL) breast. Carcass weight was taken pre- and post-chilling. The breast samples were subsequently packaged onto polystyrene trays, overwrapped and placed into cardboard boxes for dark storage at 4 degrees Celsius for either seven days (phase 1) or 14 days (phase 2). Then breast samples were placed into a retail display case maintained at 4 degrees Celsius for three days. Instrumental and subjective color measurement was performed every 12 hours during retail display. For instrumental color, the lean color of the boneless samples and the skin color of the bone-in samples were measured using a portable spectrophotometer. For subjective color, a panel of eight untrained participants were asked to evaluate the color (desirable, acceptable and unacceptable) and their willingness to purchase (would purchase, would not purchase would purchase at a discounted price) every 12 hours during retail display. Microbial analysis was conducted for samples collected upon arrival, post-chilling, post-fabrication, after dark storage at 4 degrees Celsius for seven or 14 days and after three days of retail display (n=10 per sampling point per treatment). The psychrotrophic and mesophilic bacterial counts were determined using direct plating method.