SEAFOODTRANSPORTATION SYSTEM

Introduction

PMG Seafood is a very perishable food material and needs to be cared for from the moment of catch till cooked for the table or processed in the factory. Spoilage begins as soon as the fish dies and affects its appearance odor and texture. Transport plays an important part in dealing with a perishable commodity like fish. When many indigenous and mechanized boats bring their catches ashore into numerous coastal villages, link roads between the villages and the nearest highways become essential for quick transport. Shellfish and fish destined to reach processing places are transported by trucks, trains, and sea vessels. The commercial food sector, including agriculture, food manufacturing transport and retailing is responsible for 22% of the total greenhouse gas emissions. Food distribution and retail accounts for approximately one-third of this, with food transport which includes motive power and refrigeration estimated to be responsible for 1.8 % of total emissions. Road transport refrigeration equipment is required to operate reliably in much harsher environments than stationary refrigeration equipment. Due to the wide range of operating conditions and constraints imposed by available space and weight, transport refrigeration equipment has lower efficiencies than stationary systems.

Regulations for Refrigerated Transport:

Various regulatory legislation covers temperature control requirements during the storage and transport of seafood items that requires manufacturers to have suitable temperaturecontrolled handling and storage facilities that can maintain food at appropriate temperatures and enable these temperatures to be monitored controlled and recorded. Frozen seafood products are required to be maintained at -18°C or below and fresh fish, shellfish and their products are required to be transported at temperature close to 0°C. It is recommended to use freezer bags, ice slurry, chilled seawater or refrigerated seawater wherever possible. Fresh whole fish should be kept in shallow layers of melting ice and maintained at a temperature between 0-4°C.

Components of Transportation System:

(A) Vehicles: Most of the refrigerated road transportation is conducted with semitrailer insulated rigid boxes.

A rigid semi-trailer box normally consists of expanded foam insulation sandwiched between two external skins. Each skin consists of a few millimeters of plywood covered with a glassreinforced polyester, steel, or aluminum skin. The most popular insulation is expanded polyurethane (PU) foam with cyclopentane as the blowing agent.

b. Refrigeration Units : The most common refrigeration system in use for refrigerated food transport applications today is the vapor compression system. Mechanical refrigeration with the vapor compression cycle offers a wide range of options for compressor drive methods. The choice may be based on duty required, weight, noise requirements, maintenance requirements, installation cost, environmental considerations, and fuel taxation.

c. Air delivery system: The top air delivery system is predominately used for air distribution in a refrigerated semi-trailer Refrigeration unit fans cause temperature-controlled air to circulate around the inside of the vehicle roof, walls, floor, and doors to remove heat, which is conducted and infiltrated from the outside, returning to the cooling coil via the floor or space under pallets.

d. Multi-compartment Vehicles: In multicompartment vehicles the refrigerated space is subdivided into several compartments with individual temperature set-points to provide logistics flexibility for many business operations. It is common practice for supermarket chains to deliver produce inside multi-compartment semitrailers.

e. Eutectic systems: Eutectic systems consist of hollow tubes, beams or plates filled with a eutectic solution (phase change material) to store energy and produce a cooling effect whenever necessary to maintain the correct temperature in the refrigerated container.

The Eutectic concept is different to conventional refrigeration systems in that a cold source (heat absorption) is provided by phase change material rather than direct expansion of refrigerant gas. The plates or beams that contain the eutectic are charged (frozen down) at night on mains power.

f. Cryogenic cooling system: As an alternative to mechanical refrigeration, total loss systems using liquid nitrogen or carbon dioxide injection may be used. Advantages are rapid pull-down of temperature and relative silence. For longer journeys, these systems are expensive to operate; so cryo-mechanical systems exist which combine the rapid pulldown of a total loss refrigerant with the more economical steady running of a mechanical system.

Good transportation practices:

1.Avoid unnecessary exposure to elevated temperature during loading and unloading of fish and fish products. 2.Loading to be done in such a way to ensure good air flow between product and walls, roof, and floor. 3.During transportation, all precautions should be taken to maintain the appropriate temperatures so that dis-coloration, foul smell, and microbial spoilage, possible cross contamination could be avoided.

4.Conveyances and/or containers or tankers used for transporting Fish and Fish products shall be kept clean, hygienic, and maintained in good repair condition.

5.Facilities for recording temperature or data logger should be present.