Barberries are so common around here that there would be enough for a fruit serving a day for quite a while. But there is a problem: I do not know whether or not they are edible. Are they edible in any quantity?
I often found myself following these steps from Lofty Wiseman's Survival Guide, even though I was not in a life or death emergency situation, and never had any problems. It allows you to safe check all vegetation. These methods have proved themselves on several occasions during my time in the army. I am not encouraging anyone to use this method in a non-survival situation, unless he/she feels comfortable doing so.
Always adopt the following procedure when trying out potential new food plants, only one person testing each plant. NEVER take short cuts – complete the whole test. If in any doubt, do NOT eat the plant. Should stomach trouble occur, relief can be gained by drinking plenty of hot water; do not eat again until the pain goes. If it is severe, induce vomiting by tickling the back of the throat. Charcoal is a useful emetic. Swallowing some will induce vomiting and the charcoal may also absorb the poison. White wood ash mixed to a paste with water will relieve stomach pain.
INSPECT Try to identify. Ensure that a plant is not slimy or worm-eaten. It will be past its best, with little food value other than the grubs or worms upon it. Some plants, when old, change their chemical content and become toxic.
SMELL Crush a small portion. If it smells of bitter almonds or peaches – DISCARD.
SKIN IRRITATION Rub slightly or squeeze some of the juice onto a tender part of the body (under the arm between armpit and elbow, for instance). If any discomfort, rash or swelling is experienced – DISCARD, reject in future.
LIPS, TONGUE, MOUTH If there is no irritation to the skin proceed in the following stages, going on to the next only after waiting five seconds to check that there is no unpleasant reaction:
• Place a small portion on the lips
• Place a small portion in the corner of the mouth
• Place a small portion on the tip of the tongue
• Place a small portion under the tongue
• Chew a small portion
In all cases: if any discomfort is felt, such as soreness to the throat, irritation or stinging or burning sensations – DISCARD, reject in future.
SWALLOW Swallow a small amount and WAIT FIVE HOURS. During this period eat or drink NOTHING else.
EATING If no reactions such as soreness to the mouth, repeated belching, nausea, sickness, stomach pains, griping pains in the lower abdomen or any other distressing symptoms are experienced, you may consider the plant safe.
WARNING POISON! There are two fairly common poisons in the plant world, but both are easily detectable: Hydrocyanic acid (Prussic acid) has the taste and smell of bitter almonds or peaches. Most notable example is the cherry laurel (Prunus laurocerasus), with laurel-like leaves, which contains a closely allied poison. Crush the leaves and remember the smell. Discard ALL plants with this smell. Oxalic acid, whose salts (oxalates) occur naturally in some plants, for instance wild rhubarb (mostly in the leaves) and wood sorrel (Oxalis acetosella). Recognizable by the sharp, dry, stinging or burning sensation when applied to the skin or tongue. Discard ALL plants which fit this description. • AVOID any plant with a milky sap, unless positively identified as safe (such as dandelion).
• AVOID red plants, unless positively identified, especially in the tropics. The red-streaked stalk of wild rhubarb is edible but its leaf is poisonous. Hemlock has reddish-purple splotches on its stem.
• AVOID fruit which is divided into five segments, unless positively identified as a safe species.
• AVOID grasses and other plants with tiny barbs on their stems and leaves. With a magnifying glass you can see them as hooks rather than straight hairs and they will irritate the mouth and digestive tract.
• AVOID old or wilted leaves. The leaves of some trees and plants develop deadly hydrocyanic acid when they wilt – including blackberry, raspberry, cherry, peach and plum. All may be safely eaten when young, fresh and dry.
• AVOID mature bracken (Pteridium aguilinium). It destroys vitamin B in the body, setting up a peculiar blood condition which can cause death.
I have bought dried barberries for cooking at Persian stores for many years.
One Green World has two varieties that can be bought for the fruit.