Wal-Mart, the world's largest retailer, caused a stir when it lowered its full-year forecasts this week due to pressure on US sales. Retail sales in the country have entered an upward trajectory and close competitor Target Corp has been hit by a data breach scandal - but Wal-Mart has apparently failed to capitalise. Likewise, Kellogg missed market expectations when it reported fourth-quarter numbers due to an accelerating decline in North American revenues. Here are the highlights from just-food this week.