The new rule takes effect at 10 p.m. Wednesday and restricts restaurants — along with breweries, wineries and bars — to takeout and delivery only for the first time since May. It will remain in place for at least three weeks, officials said. Wineries and breweries can continue retail operations.

“The persistent high number of cases requires additional safety measures that limit mixing in settings where people are not wearing masks,” Barbara Ferrer, the Los Angeles County public health director, said in a statement.

As expected, restaurateurs greeted the news with frustration and dismay, expressing particular concern for their employees.

“What do I think of it? It’s horrible. It’s another punch,” said Michael Simhai, the owner of Della Terra, an Italian restaurant in the Fairfax district, about 10 minutes after learning of the moratorium on outdoor dining.