In these times of hard economy and jobs an Oregon-based company that makes a range of food products, from potato salad to tortillas, plans to expand its plant in Halifax and add 500 jobs. Reser’s Fine Foods Inc. opened a 160,000-square-foot plant in the Halifax Industrial Center off N.C. Highway 903 nine years ago to make refrigerated macaroni and pasta salads and desserts like puddings and gelatins. Since then, production has ballooned from 40 million pounds a year to 100 million pounds last year. Plant manager Randy Earle said, the plant was expanded by 40 percent two years ago