Despite what many people think, the United States has no effective food weapon to use against Iran. Iran will not go hungry no matter what the United States and other countries do. Short of a naval blockade in the Persian Gulf, it is unlikely that a unilateral or international food embargo will stop the flow of food.

In late September the U.S. Department of Agriculture announced that the government of Australia had contracted to sell 520,000 metric tons of wheat to Iran. The purchase represented roughly two-thirds of projected Iranian wheat imports, almost all of which used to come from the United States. At about the same time, the Canadian Wheat Board sold 50,000 metric tons of its barley to the private trade, which in turn sold it to Iran. These are just two of the many contracts signed by the Khomeini government for food imports.

A few days later, the U.S. Embassy was seized and Americans inside were held hostage for the shah's return. These steps were an undisputedly grotesque violation of international law and human dignity. Although provoked, the U.S. government refrained from military action. Instead, it opted for measured responses to secure the quick release of the hostages. First it froze Iranian assets in American banks; then it reviewed the visas of Iranian students in the United States; next, it turned to its allies and the U.N. Security Council.

One option it still has not tried is a food embargo. The U.S. International Longshoremen's Association is boycotting food shipments leaving American ports for Iran, but this action has no effect on Australian or Canadian exports. An embargo scenario would involve an official, government-enforced halt. If expanded to include other countries supplying food, each participating government would have to intervene.

Over 160,000 tons of the Australian contract have already been shipped to Iran. Allegedly, the Australian Wheat Board contract did not include shipment and delivery costs. Frequently the board handles directly all phases of its exports. In this case, the Khomeini government had to arrange for the imports from Australia, which can be done only through companies qualifying as agents of the Wheat Board. The government selected, according to trade sources, subsidiaries of Cargill and Continental to act as its agents. These same sources indicate that the Canadian barley contract was also handled by Cargill.

Notwithstanding reports of longshoremen stoppages in Australia, official indications are that the shipments are continuing unimpeded. Each day more cargo arrives in fulfillment of earlier contracts. The Australian and Canadian sales were apparently negotiated prior to the American Embassy takeover in Tehran. But they are only commitments to sell, as opposed to actual exports. The governments and companies could have delayed shipments. Moreover, if American companies are in fact involved in these transactions, they competed for the contracts on their own volition. They were not forced, like American oil companies operating out of the Middle East, to carry out any foreign government decision.

Secretary of Agriculture Bob Bergland and other official spokesmen have indicated that Iran is experiencing considerable difficulty in gaining access to food supplies. They point to the longshoremen boycott and Tehran's decision to renege on its foreign debts. But shipments are continuing unabated and Iran is paying in hard cash for its food imports. As long as countries need its oil, it will not be short of cash.

In the unlikely event that Canada and Australia joined the United States in a food embargo effective immediately, Iran would still not be cut off.

There are other sources to go to, such as Europe, Argentina or even the Soviet Union for wheat, Thailand or Japan for rice and Brazil of South Africa for corn. International grain houses, the largest of which are American, would undoubtedly handle these transactions because of their position in the world market. A partial embargo will, therefore, be of little consequence, and a complete embargo will leak like a sieve unless governments can prevent companies from shipping to Iran.

At present the United States would be unable to ensure the private sector's cooperation short of sealing off all American ports for food cargoes or a naval blockade. When Washington receives an export document from Duluth, Minn., and the shipper reports Iraq or the Netherlands as the cargo's destination, the federal government cannot be certain that the carrying vessel will not end up somewhere else -- perhaps Iran. Export companies do not volunteer this kind of information and whatever they report is the absolute minimum required under the law.

A food embargo against Iran is not in effect and the reasons should be clear. The United States in particular is in no position to implement such a strategy even with a boost from the longshoremen. The idea of an initiative along these lines is perfectly legitimate in light of current events and is preferable to military action. The United States cannot, however, afford the embarrassment of declaring an embargo only to discover its own impotence with respect to an effective use of the so-called food weapon. We would feel the pinch more than Iran.