Sample handling after cooking may have been less than optimal. The samples were placed in 4-ounce containers, which were put into insulated containers with frozen ice packs and moved to frozen storage approximately eight hours later. The cooler and freezer temperatures were monitored. However, it is both possible and likely that some vitamin C was lost in the initial cooling phase, particularly in the lower vitamin C samples. Thus, the vitamin C content of some or all of the analyzed samples of prepared foods may actually have been higher than reported. This suggests the need for follow-up of changes in vitamin C content during the immediate postcooking period.
Cooking procedures used in the field (in both Tanzania and Haiti) included soaking steps followed by heating. Cooking times were ~20–30 minutes, including soaking. Both CSB and WSB are processed to allow briefer cooking periods, and in situations of limited fuel this would be very important. Shorter heating periods could result in greater vitamin C retention because the primary cause of loss is heating.
In theory, 30 g of the WSB or CSB fortified at the conventional level of 40 mg/100 g or the high level of 90 mg/100 g would provide 12 or 27 mg of ascorbic acid, respectively if there were no cooking losses. If ~30 percent retention is assumed for WSB gruel, the intake would be 3.6 or 11.4 mg. Similarly, for conventional-level CSB gruel, retention was estimated at 30 percent, so intake would be 3.6 mg. At the high levels (starting material >>90 mg/ 100 g), between 13.5 and 18 mg could be provided. If the intake of vitamin C was actually above 10 mg per day, this would be sufficient to prevent scurvy.