The food and beverage prices charged by in-plant cafeterias and vending machines are conditions of employment subject to mandatory collective bargaining under the National Labor Relations Act, the Supreme Court ruled 9 to 0 yesterday.

The ruling was a victory for the National Labor Relations Board, which had sided with a union in a dispute with the Ford Motor Co.

"The availability of food during working hours and the conditions under which it is to be consumed to workers," Justice Byron R. White wrote for the court.

The case involved Ford's auto parts stamping plant in Chicago Heights, Ill., where 3,600 hourly production workers are represented by Local 588 of the United Automobile, Aerospace and Agricultural Implement Workers of America (UAW).

Since 1967, the union contract has had provisions concerning cafeteria and vending services, which were provided under an agreement between Ford and ARA Services, Inc. The 1974 union contract said that Ford "recognized its continuing responsibility for the satisfactory performance of the caterer . . ."

In February 1976, however, Ford notified the UAW that prices would go up by unspecified amounts. The union requested bargaining. Ford refused, claiming that it didn't have to bargain over food prices. The NLRB supported the UAW and was upheld by the 7the U.S Circuit Court of Appeals.

The court took these other action.

Printer's Leak (on Wall Street)

Acting shortly after Chief Justice Warren E. Burger accused a court printer of leaking decisions to a television reporter, the court agreed to review the conviction of Vincent F. Chairella, who made $30,000 by deciphering "code names" in takeover bids that his employer, a financial printing firm in Manhattan, prepared for publicaiton.

Chiarella, who in 1975 and 1976 was a "mark-up man" in the composing room of Pandick Press, was found to be talking to his broker 10 to 15 times a day. He denied he ever saw, but admitted passing at least 640 times, signs warning employes against using for their private benefi information they came across on the job.

During the period in question, Pandick got materials on four tender offers and one merger in which the customer, to preserve confidentiality, either omitted or encoded the names of the target corporations until the press run on the night before release.

In violation of Pandick's rules, Chiarella used data in the drafts, such as the market in which a stock was traded, the number of shares outstanding, and the high and low bids in the previous year, to determine the identity of the target companies. Then, in 17 separate transactions, he bought shares in companies destined for acquisition.

By undisclosed means, the Securities and Exchange Commission found out about Ciarella's activities and, in 1977, instituted the first criminal prosecution based on use of non-public information stemming from sources other than a corporation selling or buying the securities in question.

Chiarella, in addition to being fired by Pandick, was convicted on 17 counts of securities fraud, and drew 13 concurrent one-year sentences and four suspended sentences. He actually faces jailing for only a month and probation for five years.

A divided 2d U.S. Circuit Court of Appeals, in a ruling that now will be reviewed, upheld the conviction. Dissenting Judge Thomas J. Meskill said that under existing law, Chiarella could properly be convicted only if he had had: "a duty of disclosure to the sellers of target stock."

"Just Compensation"

The court ruled 8 to 0 that when the government takes for public purposes land owned by a church or other non-profit entity, the Constitution's "just compensation" requirement allows the basis for payment to be fair-market value rather than the cost of substitute facilities. The decision was a vicory for the government in a case involving the Southeastern Pennsylvania Synod of the Lutheran Church in America.

Realty Commissions

The court agreed to review a decision that federal laws against price fixing don't apply to an agreement among all of a city's real estate brokers to charge identical commissions for hom sales because such sales aren't in interstate commerce. The decision was made by the 5th U.S. Circuit Court of Appeals in a case from New Orleans.

Virgin Islands Refinery

The court denied a plea by the American Maritime Association, composed of steamship companies, to review a ruling that the Jones Act of 1920 allows foreign-flag tankers chartered by Amerada Hess Corp. to carry Alaskan crude to its Virgin Islands refinery and petroleum products from the refinery to the East Coast.

State Corporation Taxes

The court agreed to decide whether a state, in computing the income-tax base of a corporation, can include dividends from its foreign subsidiaries when the coporation is headquartered in another state and, only in that state, receives the dividends and from it controls the subsidiaries.

Ruling against Mobil Oil Corp., the Vermont Supreme Court upheld the inclusion of dividends Mobil received at its New York headquarters from subsidiaries abroad.

Backed by the National Association of Manufacturers and a unit of the Council of State Chambers of Commerce, Mobil contends it is exposed to the risk of impermissible taxation of its dividends by multiple states.

In addition to Vermont, Maryland and six other states apportion dividends under individual formulae, regardless of the commercial domicile of a corporation.