Many of the largest food producers in the U.S. are struggling to meet demand on specific popular products in the face of ongoing problems ranging from packaging shortages to labor issues. In emails viewed by CNN, several have told grocery chains that certain items will be allocated in limited quantities and are urging stores to cancel any planned promotion on scarce products to help prolong supplies as the holiday season ramps up. It also appears that such constraints are already taking a toll on the availability of certain items. During the week ending on Oct. 3, nearly 15 percent of frozen foods, 15 percent of candy, 16 percent of snacks, 18 percent of beverages, and 18 percent of bakery items were out of stock at stores, according to data from IRI, a data analytics company that track stock levels at major grocers and big box stores across the U.S. These numbers represent a steep jump from before the pandemic when it was typical to see seven percent to 10 percent of products out of stock on shelves. However, experts also pointed out that not all products will be affected evenly. Manufacturers will often shift focus and prioritize producing their best-selling items when supplies run thin, Krishnakumar Davey, president of IRI’s strategic analytics practice, told CNN Business. Such conditions could mean that certain niche flavors, styles, or types of products could be harder to find than their more popular counterparts. According to Chieh Huang, CEO of online bulk goods retailer Boxed, the current conditions may not be short-lived. In an interview with CNN Business, he said that such “allocations are the new norm.” But, he added, “the industry is better off than we were this time last year.” So, which items are becoming difficult to find? Read on to see the popular foods that are disappearing from grocery store shelves nationwide. RELATED: This Popular Pepsi Drink Is Disappearing From Store Shelves. According to an email sent to at least four grocery distributors last month by parent company Kellogg, Rice Krispies Treats snacks “will remain below service expectations” for the rest of 2021, CNN Business reports. The email went on to urge grocers to hold off on offering sales on both the lunchbox staple and the company’s Corn Pops cereal “to allow for recovery.” But it may be even longer than expected before these products come back into stock, as Kellogg cereal factory workers announced they would be going on strike on Oct. 5.ae0fcc31ae342fd3a1346ebb1f342fcb If you’re planning on whipping up one of your favorite annual dishes over the holidays, you may want to do a quick inventory of your spice cabinet first. In an email sent to two separate distributors on Sept. 20, a representative from spice company McCormick admitted that packaging issues were affecting stock of certain products, saying, “our U.S. bottle supplier shut down due to a COVID-related issue and we have not received bottles for several weeks.” However, the shortage will likely not affect the company’s entire line of products. In an email to CNN Business, Lori Robinson, a spokesperson for McCormick, said that “Gourmet is the only product line impacted by this packaging shortage.” She also assured that the company’s iconic spices with their trademark red caps would still be available to substitute for the missing products. RELATED: Walmart Shoppers Are Outraged the Store Is Getting Rid of This. With Halloween just around the corner, fans of certain popular candies may get more trick than treat this year, thanks to ongoing shortages. In an Oct. 1 email to a grocery distributor, parent company Mondelez says there is “limited availability” on some of their items such as Sour Patch Kids, Swedish Fish candy, and Toblerone chocolate “due to supply chain constraints.” The company estimated that the “recovery date” for the affected products would likely be sometime in February or March. Reaching into the freezer for a pint of your favorite ice cream can be the ultimate destresser after a long day. But according to an email sent to a distributor by Ben & Jerry’s parent company Unilever on Sept. 14, “labor shortages continue to drive a limited ability to meet demand” on some of their products. The company has said it would focus on making more of its popular core flavors while slowing down production on some of its more niche offerings, including its Cold Brew Caramel Latte and Ice Cream Sammie flavors. For more product and retail news sent straight to your inbox, sign up for our daily newsletter.  Eating at home more during the pandemic has led plenty of people to rely on heat-and-serve meals more often. But the increased popularity has led some popular brands to become scarce, including Marie Callender’s frozen pot pies. In a Sept. 27 email to a distributor, parent company Conagra said it would be allocating shipments of Marie Callender’s 10-ounce and 15-ounce pot pies through Nov. 29 after it “encountered packing material challenges from our tray and carton supplier resulting in a production interruption,” CNN Business reports. RELATED: The Latest Major Shortage Is Happening at the Worst Time Possible.