N.J. Stat. § 40:62-137: Execution of contract

All such contracts shall be in writing, and shall be executed by the president and secretary of the commission, on behalf of and in the name of the commission, and under its seal. No party shall be allowed to enter upon any work or furnish any material until the contract shall have been so executed. Every person entering into any such contract with the commission shall give satisfactory security for the faithful performance thereof according to its terms, with surety to be approved by the commission.