A huge market opportunity awaits online retailer Amazon as it plans to launch its own private-label brands of perishable groceries including milk, cereal and baby food. However, the e-commerce giant must overcome challenges in quality, the distribution logistics of perishables and customer preferences that the firm hasn’t previously faced. “ … in a time-pressured society,” according to Amanda Nicholson , professor of retail practice at Syracuse University’s Whitman School of Management. Her optimism came with a crucial rider, however: With food items, especially private-label brands, “[consumers] need a sense of faith that this is going to be a good product, and that takes some time to build,” she said, noting that upscale supermarket chains like Wegmans have built that reputation over time.…