With job losses growing and working hours shrinking, many paychecks are eroding, prompting millions of families to cut their spending. Soaring prices for food and gasoline are overwhelming modest wage gains for most workers, leaving households with even less money to spend. All of which deprives struggling businesses of sales, prompting them to shed more workers, sending the cycle down another turn. Starbucks announced on Tuesday that it would close stores and eliminate up to 12,000 jobs, about 7 percent of its work force.