At a Publix store in St. Petersburg, Florida, handmade signs limit customers to two packages of beef, pork and Italian sausage. In Toronto, shoppers at a west end Loblaws can’t buy more than two dozen eggs and two gallons of milk. Spoiled for choice before the pandemic, North American shoppers are finding they can’t get everything they want as grocery stores ration in-demand items to safeguard supplies. While the panic that swept through supermarkets in the first weeks of the coronavirus lockdowns has eased, people are still filling fridges and pantries with stay-at-home staples from flour and yeast to pasta sauce and meat.

The strong demand comes at a time of supply disruptions as food makers adapt to dramatic shifts in buying patterns and some processing plants close as workers fall ill. As a result, stores are restricting purchases to prevent items from vanishing from shelves. For shoppers, that can be unnerving. “It’s not a shortage, it’s just that it needs to get from the supplier throughout the supply chain to the stores,” said Diane Brisebois, president and chief executive officer of the Retail Council of Canada. “There’s been an unexpected increase in demand for those products, and if those demands continue, it might take a bit longer to get them to the shelves.”

Overall, there’s enough retail supply, said Heather Garlich, a spokesperson for FMI, a food industry association that represents retailers and producers. But there have been “sporadic challenges” with high-demand products, and 49% of U.S. shoppers report their supermarket has had products out of stock, according to the industry’s tracking. On popular items, “they could consider limits based on where the grocer may be located and when their supplier or wholesalers can get them product,” Garlich said.

The dizzying variety of foods on grocery shelves has long been a trademark of North American supermarkets. That’s now changing, leaving shoppers worried. Some manufacturers have shifted their focus to making more of just a few core products, which makes it easier for retailers to restock supplies.“The thing I’m struck by, in the U.S., we’re so used to walking down a supermarket aisle and having thousands of choices,” said Heidi Heitkamp, a former North Dakota Senator and current member of alliantgroup’s strategic advisory board. “Now that’s not what people see on the shelves and it’s a little unnerving. But what everyone should be grateful for is that you can walk into any supermarket in a major metro area and you can find food to eat. That’s a critically important national security concern.”

There are signs that panic buying is waning and shoppers are returning to more traditional patterns. U.S. packaged food sales rose 24% in the week ended April 4 from a year ago, slowing from a gain of 32% a week earlier, according to data compiled by Nielsen. Limits on the number of visitors per store are also affecting sales.