By Ahmed Aboulenein and Chris Gallagher WASHINGTON (Reuters) -A military cargo plane carrying the first shipment of infant formula from Europe to help address a critical shortage in the United States landed in Indianapolis on Sunday, but a top government official noted that much more needs to be done. A Feb. 17 recall by top baby formula maker Abbott Laboratories and the closing of its manufacturing plant in Sturgis, Michigan has created one of the biggest infant formula shortages in recent history for U.S. families. “This is an important step, but it is by no means the only step that must tak…