ALEXANDRIA, Va. – Feeling the aftershock of the Amazon-Whole Foods partnership, food companies are trying to attract and sell to online shoppers. It’s not easy, according to a report from Fooddive.

Selling online has many benefits. Companies cut out the middleman and can better manage their supply chain. They control the shopper’s journey from arrival at the website to checkout, and they can tell their brand’s story while building relationships with customers. But doing this isn’t cheap.

Successful e-commerce efforts must be supported by strong marketing—especially in the United States, where grocery e-commerce isn’t as common as in other countries. This requires food companies to invest in both organic and paid searches, ratings, reviews, creative copy and banners to promote their products online.

General Mills bundles food products together to sell what it describes as “meal solutions.” Like other large companies, General Mills has a wide range of products and can offer a one-stop shop to consumers who don’t want to place multiple orders on different sites.

Personalization also attracts the online crowd. The website for the Kellogg-owned Bear Naked brand lets consumers create and order their own granola. They can choose ingredient combinations recommended by a professional chef or mix ingredients to produce their own personal cereal.

At the Ben & Jerry’s website, customers can buy ice cream in bulk or limited-time, online-only flavors, such as Marshmallow Moon, which was developed in partnership with popular “Tonight Show” host Jimmy Fallon.

E-commerce platforms also can be used to test new or long-term products since more information can be collected online faster than surveying shoppers one-on-one in-store.