For instance, Michael Foods, a division of Post that is one of the biggest egg product suppliers in the country, sells an "enzyme-modified whole egg product," precooked egg white products and liquid eggs in a number of configurations, among other things.
Those eggs are used by grocery chains, restaurants, food service companies and food manufacturers in a wide variety of products, including mayonnaise, ice cream, cookies, muffins, batter for breading and French toast.
At Panera Bread, for example, eggs are used in some baked goods, as well as in its egg and egg white breakfast sandwiches and soufflés. "Eggs are a relatively small part of our menu, and at this moment our supplies are intact," said Ronald M. Shaich, chief executive of Panera. "But we're going through a series of reviews about how to ensure supply lines are there."
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Paul Ray, Panera's vice president for sourcing, said there was is a lot of confusion about how extensive the impact on the egg supply would be and sometimes even about where eggs are used in the supply chain — suppliers themselves have suppliers, which in turn have other suppliers.
"Just accumulating information can be difficult — this continues to materialize," Mr. Ray said. "Two weeks ago, it was an issue but not as significant an issue as it has become in the last 10 days."
Many companies declined to speak about the indirect impact avian flu is having. Food businesses are notoriously secretive about their suppliers for competitive reasons, and some worry that reports of shortages will somehow raise concerns among consumers. Slightly more than half of consumers surveyed by the NPD Group, a consumer research firm, had concerns about avian flu and its implication for health and food safety — even though the Food and Drug Administration has repeatedly said it is unlikely that eggs in the marketplace would be contaminated in any way, and no chance for harm if eggs are cooked properly.
In a call with analysts on May 8, Robert V. Vitale, chief executive of Post, said the company had a shortfall of about 165 million pounds of liquid eggs.
Less than a week later, three more facilities that supply the company's eggs — two with flocks that it owns outright and one with flocks owned by a supplier — had been hit with avian flu.
In total, the company has lost one-quarter of its egg supply, which means it cannot fulfill all of its contracts to supply egg products to other businesses. In some cases, Post will have to buy eggs on the spot market to meet its obligations — and Mr. Vitale said in the conference call that the only thing he knew about avian flu for certain was that prices on the spot market would go higher. The company said that Michael Foods, which Post bought last year for $2.45 billion, would discontinue some products and take "appropriate pricing actions to offset reduced egg supply and increased operating costs."
Egg prices in general are moving up, according the United States Department of Agriculture's weekly report, and there were not enough liquid eggs available for purchase in the spot market to cover demand last week.
Bon Appétit Management Company, a food-service business owned by the Compass Group that manages more than 500 cafes in universities, museums, corporations and other institutions, is also mulling its options. "We are already working with our chefs to change recipes to eliminate eggs," said Fedele Bauccio, chief executive of Bon Appétit. "There are lots of things we can change on the menu — but that's not going to solve the total problem."
Mr. Bauccio sits on the board at Hampton Creek, which last week began accelerating its efforts to develop egg-free muffin, pancake and other mixes used in the food service business and by grocery store operators that have in-store bakeries, like Costco Wholesale. The original plan was to introduce such mixes next year, but Hampton Creek now hopes to have them early this summer.
The question is whether companies buying Hampton's Just Mix egg substitute to offset tight supplies of eggs because of avian flu will stick to the change when the egg industry recovers. Just Mix is 48 percent cheaper than conventional eggs, according to Hampton Creek — and Mr. Tetrick is weighing promotions that would make it an even better bargain.