By Dan Weil Food-industry executives say the pressure could continue for some time, even after the Covid omicron variant passes, a media report says. The Covid omicron variant is stressing the U.S. food system, as it’s infecting workers all along the food supply chain, keeping them at home. That means some food is missing at grocery stores, The Wall Street Journal reports. In Massachusetts, deliveries of fish to supermarkets and restaurants have slowed because workers are out. And a southeastern grocery chain, Piggly Wiggly, lost about one-third of the workers at its distribution centers, forc…