a safety or quality concern with food products that are already on the market has been recognized, a recall is issued to prevent further damage to the public. the batch number tracking technique is one of the methods which can be used by manufacturers to recall contaminated food products. in 2015, 19 people in the us suffered food poisoning caused by e. coli o157:h7 after consuming costco rotisserie chicken salad. health officials issued a recall on all the uneaten salads with batch number 37719.