Given grocery stores tend to use the currency corresponding to their government's authorized legal tender for use in payment of debts: a lot of small things. A select number of stores in different regions accept bitcoin one way or another, word-of-mouth to support purchasing with Monero through similar systems can encourage practical consideration of it. It will take the slow expansion of Bitcoin-accepting businesses to also accept Monero as value that can benefit the business. In general, I don't know of any specific grocery store in my region that accepts crypto, Monero has an uphill battle to see grocery deployment.