Certain packaging, storage conditions facilitate production of vacuum-packaged shrimp.

Shrimp is the most valued shellfish product in the United States, and its production, consumption and imports have increased significantly in the past few years. However, shrimp is highly perishable and, like other crustaceans, the metabolic changes that occur after its death can deteriorate shelf life if the product is not treated properly.

Scientists at Mississippi State University evaluated the influence of various cooking and packaging methods on the consumer acceptability and shelf life of ready-to-eat shrimp. Their work reveals the potential for producing vacuum-packaged ready-to-eat shrimp if it is processed and stored at less than 3 C under conditions that will prevent the formation of botulinum toxin.

In experiments, fresh Gulf of Mexico brown shrimp (Penaeus aztecus, medium) were individually quick-frozen on the day of harvest and kept frozen until they were used. The shrimp were peeled and then cooked at three time-temperature combinations: 63 C for 15 seconds; 85 C for 5 minutes; and 93 C for 5 minutes.

The shrimp were packaged under air, carbon dioxide and vacuum conditions. The treated samples were stored from nine to 50 days at 2 C, depending on the shelf life of each treatment. The researchers evaluated odor using a nine-point hedonic scale to determine consumer acceptability. They used descriptive sensory analysis to determine shelf life. Agglomerative hierarchical clustering was also utilized to group consumers together based on their preference for the packaging treatment used.

Air, carbon dioxide and vacuum-packaged treatments generated shelf lives of from five to nine, 20 to 25, and 20 to 30 days, respectively. The 63 C-15 second cooking technique had a shorter shelf life than its 85 C and 93 C counterparts for all packaging methods. On average, vacuum-packaged samples were liked moderately and were preferred over samples packaged in carbon dioxide and air by sensory panelists.

Panelists were grouped into four consumer clusters in which greater than 70% of consumers determined that all treatments were acceptable. There was greater than 90% acceptability for the vacuum-packaged samples.

Further information. Linda Andrews, Food Science Institute, Mississippi State University, Campus Mailstop 9385, Coastal Research and Extension Center, 2710 Beach Blvd., Suite 1-E, Biloxi, MS 39531; phone: [phone]; fax: [phone]; email: [e-mail].