CARBON-MONOXIDE, NITRIC-OXIDE, AND NITROGEN-DIOXIDE LEVELS IN GAS OVENS RELATED TO SURFACE PINKING OF COOKED BEEF AND TURKEY

Carbon monoxide (CO) and total nitrogen oxide (NOx) levels were monito red during meat cookery with a standard Ovenpak and a new ultralow-NOx (ULN) cyclonic gas burner. With the standard burner, CO varied from 1 03 to 152 ppm, NOx was 1.3-10.7 ppm, and surface pinking was observed on both beef and turkey. The ULN burner at optimal efficiency produced only 6.7 ppm of CO and 1 ppm of NOx, insufficient to cause surface pi nking. To determine the relative contribution of CO and NOx to pinking , trials were also conducted in an electric oven with various pure gas es. Pinking was not observed with up to 149 ppm of CO or 5 ppm of NO. However, as little as 0.4 ppm of nitrogen dioxide (NO2) caused pinking of turkey rolls. Beef roasts were pink at >2.5 ppm of NO2. Thus, pink ing previously attributed to CO and NO in gas ovens is instead due to NO2, which has much greater reactivity than NO with moisture at meat s urfaces.