Pesticide residues
Dates are fumigated to kill insects, often with methyl bromide (CH3Br) (Glasner et al., 2002). The maximum residue level for methyl bromide on dried fruits was set at 2 mg/kg by the Codex Alimentarius (Codex Alimentarius, 2011). Other pesticides are used, including carbamates and organosphosphates, which may leave residues (Khan et al., 2001).
In organic date palm production, carbon dioxide is used instead of methyl bromide (Glasner et al., 2002).
Steroid compounds
The presence of steroid compounds in date pits, notably estrone, progesterone and estriol, has been known since the 1950s, though the actual effects of these compounds on sheep growth and reproduction have yet to be clearly demonstrated (Barreveld, 1993; El-Gasim et al., 1995; El-Din et al., 2001). However, treatments with hexane and diethyl ether (combined in some cases with germination) have been proposed in order to decrease the amount of steroids (El-Din et al., 2001).