Microbiological quality and shelf life of ready-to-eat sandwiches stored at ambient and chilled temperatures

Abstract

Sandwich is a kind of healthy snack that is gaining popularities in Malaysia. It is considered as ready-to-eat food (RTE) that can be prepared at home or buy at retail shop. It is important to maintain the shelf life of product because of the hot climate and tropical in Malaysia. This study was conducted to examine the microbiological quality and assess the level of unsatisfactory in sandwiches after storage at 48 hours at 28 C. Sample of sandwiches with different fillings were prepared under controlled conditions: tuna sandwich with salad, tuna sandwich without salad , egg mayonnaise sandwich with salad and egg mayonnaise sandwich without salad and kept at chilled temperatures ( 4±2 ° C and 7 days at 4 ° C). Generally, sandwiches with salad showed higher microbial load compared to the sandwich without salad. It is suggested that salad contribute to a higher microbial load in the sandwiches. Raw ingredients of sandwiches were also analyzed and iceberg lettuce had highest water activity and microbial load among all the raw ingredients due to its convoluted surface area. Escherichia coli were detected at low level in the sandwiches with and without salad when stored at room temperatures. However, ° C) and room temperatures (28±2 ° Escherichia coli were only detected in the sandwiches with salad during storage at chilled temperature. Salmonella spp and Listeria monocytogenes were not detected in all of the sandwiches.