What is the test for unanimous verdicts in a criminal case?

It is well settled that a judgment of conviction cannot be entered unless the jury expressly finds against the defendant upon the particular issue presented by the charging information as reflected in the verdict forms. (People v. Bratis (1977) 73 Cal.App.3d 751, 763, 141 Cal.Rptr. 45.) A jury's unanimous finding, however, need not be reduced to writing. The formal procedures applicable to criminal cases contained in sections 1149, 1162, 1163 and 1164 do not require a verdict to be in writing. (Stone v. Superior Court (1982) 31 Cal.3d 503, 511, fn. 4, 183 Cal.Rptr. 647, 646 P.2d 809.)