The Effects of Varying Gas Concentrations and Exposure Times on Colour Stability and Shelf-Life of Vacuum Packaged Beef Steaks Subjected to Carbon Monoxide Pretreatment
There is an emerging demand for more value-added meat packaging technologies which enhance meat quality. Overall, colour is the most important quality trait judged at point of purchase as sensory traits cannot be physically assessed prior to consumption (Carpenter, Cornforth, & Whittier, 2001; Van Rooyen, Allen, Crawley, & O’Connor, 2017). Consumers use colour as an indicator of freshness and wholesomeness and this influences perceived meat quality (Carpenter et al., 2001; Issanchou, 1996), while discoloration is associated with unwholesomeness (Faustman & Cassens, 1990) and leads to economic losses (Kropf, Hunt, & Piske, 1986) and food waste. Packaging directly affects the colour and quality of meat (Bernués, Olaizola, & Corcoran, 2003) but high oxygen MAP which is widely used to enhance meat colour negatively affects tenderness (Clausen, 2004; Tørngren, 2003). Innovations in meat packaging which enhance colour coupled with increased tenderness would greatly assist the meat industry. Vacuum packaging permits prolonged storage in an anoxic environment favouring tenderness but has a negative effect on meat colour. Carbon monoxide (CO) applied as a pretreatment prior to vacuum packaging would enhance the colour and tenderness (Van Rooyen, Allen, Gallagher, & O’Connor, 2018). CO binds to myoglobin to form carboxymyoglobin and produces a much more stable cherry red colour compared to oxygen (oxymyoglobin) (El-Badawi, Cain, Samuels, & Anglemeier, 1964). Legislation on the use of CO in meat packaging varies globally. The EU prohibited the use of CO in meat packaging systems due to concerns it might be used to mislead consumers by presenting microbiologically spoiled meat with an attractive colour so that consumers may falsely perceive the meat as “fresh” since the colour is retained (European Commission, 2001). This would be a major consumer safety concern as safety is considered a prerequisite by consumers (Van Wezemael, Verbeke, Kügler, de Barcellos, & Grunert, 2010)
