PARIS (Reuters) -Food retailer Casino, which previously expected its French retail operating profit to grow, on Friday cut its 2021 guidance, now seeing “a slight decrease”, blaming a decline in the country’s food market in the fourth quarter. Casino said France’s food retail sector had declined by a bigger than expected 3.7% in the fourth quarter of 2021. France was among the European countries hardest hit by the coronavirus at the end of last year. Casino said it now expects a slight decrease in 2021 EBITDA (earnings before interests, taxes, depreciation and amortisation) in its French retai…