99 Effects of replacing monensin and tylosin in finishing cattle diets with essential oil and/or benzoic acid on meat color and oxidative stability of ribeye steaks and ground beef

Abstract

Abstract This study examined the effects of replacing monensin and tylosin with essential oils and/or benzoic acid in finishing cattle diets on beef color stability and lipid oxidation during a simulated retail display period. The longissimus thoracis (LT) and semimembranosus (SM) muscles were obtained from 63 steers that were fed for 98 days on 1 of 5 finishing diets: no additional supplement (CON), monensin/tylosin (M/T), essential oils (EO), benzoic acid (BA), or a combination of essential oils and benzoic acid (COMBO). Instrumental color measured with a Minolta colorimeter and visual discoloration evaluated by two trained panelists were recorded daily for three beef products placed under simulated retail conditions, until a 60% surface discoloration was observed. The three beef products evaluated were LT steaks, and two types of ground beef patties manufactured with the SM muscles (lean – no additional fat and regular – 25% added fat). The thiobarbituric acid reactive substances (TBARS) assay was used before and after the shelf life display to determine the degree of lipid oxidation for products during the display. Data were analyzed as a randomized complete block design with the GLIMMIX procedure of SAS using repeated measures. Results indicated a treatment by day interaction (P < 0.0001) for visual discoloration and instrumental color of all three products. At the end of the display period, products from the COMBO diet had on average the least amount of visual discoloration and the greatest a* (redness) value, while the CON steaks and M/T ground beef had the most discoloration and the lowest a* values. TBARS values at d 0 and d 7 did not differ (P > 0.23) among treatments for all three products. Overall, supplemental ingredients in feed did not affect the color and degree of lipid oxidation of steaks and ground beef to a level deemed detrimental.