Kroger (NYSE: KR) recently posted second-quarter earnings numbers that, while keeping the retailer on track to meet management's full-year targets, disappointed investors. The supermarket giant's sales growth trends didn't accelerate meaningfully, as they have for rivals like Walmart. And Kroger also announced lower profitability due to cutting prices and spending heavily on its e-commerce business.Following the results, CEO Rodney McMullen and his team held a conference call with analysts to put those trends into perspective.