Calistoga’s largest employer, the Calistoga Beverage Co., is slashing more than 75 percent of its work force because of sluggish sales of bottled water and a decision to shift production to plants in Southern California. <br />Parent company Nestlé Waters gave layoff notices to 80 workers at the bottling plant on the east side of Calistoga, namesake for the iconic brand founded in 1924. <br />The layoffs are in response to poor sales for other brands in the Nestlé Waters portfolio. U.S. sales of nonalcoholic beverages are expected to grow only 1 percent this year, with little increase projected next year as consumers cut back on purchases in the face of higher energy and food costs, job losses and falling home values.