The goal of this Delaware Sea Grant strategic priority is to increase the economic competitiveness and sustainability of businesses and industries dependent on the ocean and coast.

The following two Marine Commerce and Transportation projects have been funded by Delaware Sea Grant for the 2005–2007 period:

• An Economic Analysis of Beach Use in the Mid-Atlantic Region
  
  
• Use of Antimicrobial Packaging Films to Control Listeria monocytogenes in Fish and Fish Products
  
  

For additional information, please also see our latest annual report.

Delaware's beaches are one of its greatest resources — they provide homes to many different species of marine life, protect the mainland from storms, and even bolster the state's economy through the countless number of tourists that visit each summer.

Unfortunately, maintaining the beaches can be an expensive proposition. Sand that is washed away during winter storms must be replaced. At the same time, sand is needed to widen the beaches as sea level continues to rise and encroach upon them. At what point does this process of beach nourishment become too expensive?

In previous Sea Grant research, marine economist George Parsons developed a model for estimating the economic value of 62 beaches in the Mid-Atlantic region. He based this model on information gathered from Delaware residents on beach characteristics such as length, width, boardwalks, easy access, and parking and the frequency in which the public uses a particular beach.

In the current study, Parsons will update this model to include day, short-overnight, and long-overnight visits to beaches as well as information on policy issues such as pollution, beach fees and safety. In addition, although he will focus on Delaware's ocean beaches — 14 beaches over a 25-mile coastline, he will gather data from residents in the Mid-Atlantic region.

"The model can be used to predict how visitation patterns change with changes in demographics in the region and changes in characteristics of the beaches such as a narrowing or closure of a beach," says Parsons. "The model also can be used to value beach nourishment projects, beach closures that may occur due to oil spills or other events, changes in amenities such as congestion and pollution, and impacts due to sea rise."

In their lab at the University of Delaware, Dr. Haiqiang Chen and Ph.D. student Swahela Neetoo test the effectiveness of antimicrobial packaging on smoked salmon.

According to U.S. Department of Commerce fishery statistics, Delaware fishermen harvested 5,857,268 pounds of finfish and shellfish worth over six million dollars in 2002. However, getting the seafood to market in a timely manner is a key factor in keeping this industry alive because seafood is highly perishable, and its deterioration is largely the result of bacteria.

"Seafood is usually refrigerated during its distribution and marketing to keep it from spoiling," says Chen. "However, refrigeration cannot prevent the growth of Listeria monocytogenes, a bacterium that can cause serious illness and death."

Research has shown that modified atmosphere packaging (MAP) also can extend the shelf life and maintain the high quality of seafood by inhibiting bacterial growth. MAP is a process where the atmosphere within the package is either entirely removed (vacuum packaging) or altered.

Unfortunately, MAP does not significantly inhibit the growth of L. monocytogenes. In addition, processes used in the production of smoked salmon also are not able to successfully eliminate this organism in seafood.

Antimicrobial packaging has gained attention in recent years to control bacterial growth in food. This type of food packaging uses antimicrobials in packaging films that come in direct contact with the surface of the food to control the growth of microorganisms.

In this new Sea Grant project, food scientist Haiqiang Chen, seafood specialist Doris Hicks, and microbiologist Dallas Hoover will investigate the use of nisin, a natural preservative derived from the fermentation of bacteria found in milk, to control L. monocytogenes in seafood products as well as to extend the shelf life of seafood products. The effectiveness of this preservative will be evaluated in two different types of food-packaging processes on cold-smoked salmon.

Both processes will look at the effectiveness of using nisin in antimicrobial packaging film to inhibit the growth of L. monocytogenes in salmon. However, in the second process, the salmon also will be packed in a modified atmosphere in addition to incorporating nisin in packaging film. Both processes will be tested under various levels of nisin in the packaging film.

Chen adds that the development of a processing technique that would ensure the microbial safety of seafood products and extend their shelf life will be of benefit to both the seafood industry and consumers.