A recently completed large-scale field study confirms the economic benefits that dietary vitamin E supplementation can bring to the entire beef industry by lengthening meat's color case life in the supermarket. The new study (Westcott et al., 1996) demonstrated on a commercial level what earlier research had already shown on a smaller scale: Namely, that vitamin E supplementation can significantly delay the discoloration of beef, thereby reducing retail level discounting and allowing the industry to retain over $30 more value per carcass.
Dr. Dan Schaefer of the University of Wisconsin has estimated the total economic cost of discounting or discarding of beef due to discoloration at 5 percent of total retail sales of fresh beef, or about $1.1 billion a year. Because retailers anticipate this loss when figuring their margins, they eventually pass much of the cost back through the production chain as lower prices or pass it along to consumers as higher retail prices that reduce demand. The new field study found that the recouped income from less discounting and discarding represents 3.0 to 3.2 percent of the carcasses' value as boxed beef.
Vitamin E in the meat tissue protects against discoloration by delaying oxidation of myoglobin, the pigment that accounts for most of beef's bright red color. The vitamin can also protect muscle cells against lipid peroxidation that causes off flavors and odors--which is why the pork and poultry industries are also exploring vitamin E supplementation to improve meat quality. In beef, however, color deteriorates first, and the bright red or pink appearance is such a key component of consumer acceptance that "browning" forces retailers to mark down meat before off flavors and odors can develop.
The threshold for delaying this discoloration appears to be vitamin E levels of 3.0 to 3.7 µg/g in the muscle tissue, according to Faustman et al. (1989). To reach those levels in finished cattle, there is some leeway in feeding regimens, depending on the level and duration of dietary supplementation. However, Smith (1996) noted that in studies at Colorado State University, vitamin E supplementation of 500 IU per head per day for 84 to 126 days accomplished that level. Today, Colorado State researchers recommend 100 days of feeding 500 IU per head per day in cattle raised for the domestic beef market and 1,000 IU per head per day in cattle raised for export.
In the recent study, three commercial feedlots finished 235,000 head of cattle that received either a routine finishing diet or the same diet with 500 IU of vitamin E per day. The cattle were then processed by three packers, and the meat was marketed through four large supermarket chains.
At the retail level, Westcott et al. (1996) measured improvements in both color case life and discount percentages with vitamin E supplementation. Both are of concern to retailers since a longer color case life offers benefits even when discounting isn't an issue. Furthermore, the two are roughly, rather than perfectly, correlated. Both vary with the cut of meat--as do vitamin E tissue concentrations and the improvements with vitamin E supplementation.
With chuck cuts, for example, Westcott et al. found that discounting was reduced by 7.1 percentage points (19.4 versus 26.5 percent) in beef from vitamin E supplemented cattle compared to unsupplemented controls. This resulted in an average of five fewer cuts being discounted per carcass. Average color case life was increased by nine hours to 49 hours.
Discounts to middle meat cuts are rarer but still significant. For example, one in every 10 strip loin steaks from control cattle was discounted or discarded from the retailers' shelves. However, vitamin E supplementation reduced the pull rate to one in every 14 and increased color case life by approximately eight hours.
Vitamin E supplementation produced greater increases in color case life and recaptured value in the round cuts, with 16 of the 19 round cuts having improved color case life when from supplemented cattle (Figure 1). For instance, the number of top round steaks that had to be discounted fell to 14.7 percent, compared to 28.5 percent in controls. Color case life for these steaks was lengthened by 11 hours.