NCBA has created an extensive FAQ document, which includes the following answer regarding if packing plants are planning to close or reduce operations in light of the coronavirus:

Packing plants are working to ensure worker health and safety so that employees can continue to work, and plants can continue to operate.  They are working on contingency plans in the event employees become ill. USDA remains committed to keeping the food supply chain safely operating. Inspectors and graders will continue to be in plants doing their job. In the event of sick or exposed employees the USDA has contingency plans in place to keep inspections going.