198 Meat refrigeration Table 9.4 Types of road vehicle investigated in Meat Research Institute(MRI) Survey(1970-71) System No of cases Liquid nitrogen Insulated non r 9287 Uninsulated Source: Cutting and Malton, 1972. The uninsulated vehicles were mostly 10cwt(0.5 ton) delivery vans, with no partition between driver and load Since that time the intensifying demand from legislation and retailers for ower delivery temperatures, has put increasing pressure on fleet operators to improve temperature control. However, there are substantial difficulties n maintaining the temperature of chilled foods transported in small refrig erated vehicles that conduct multi-drop deliveries to retail stores and cater ers. The vehicles have to carry a wide range of products and operate under diverse ambient conditions. During any one delivery run, the chilled product can be subjected to as many as fifty door openings, where there is heat ingress directly from outside and from personnel entering to select and remove product. The design of the refrigeration system has to allow for extensive dif- ferences in load distribution, dependent on different delivery rounds, days of the week and the removal of product during a delivery run. The ability of a refrigeration system to respond to sudden demands for increased refrig- eration is often restricted by the power available from the vehicle. All these problems combine to produce a complex interactive system In the UK, current sales of chilled foods are expanding. The overall market worth for chilled foods increased from f5. 8 billion in 1992 to f6.2 billion in 1993. In the meat industry the traditional range of pies, pasties, sausages and cooked meats has been rapidly developed with the addition of fermented meats, restructured products, Kievs, salads, stir fry products, and vegetarian burgers and rissoles. Traditional meat product manufactur- ers are now aiming to extend their range of products to include items such as gourmet-style meals without artificial colours, flavours or preservatives. Retailers are discovering that considerable quality and economic advan tages can be derived from maintaining chilled products at temperatures far closer to their initial freezing point. Increasingly, fleet operators will be forced to deliver chilled foods at temperatures between 0 and 2C. 9.3.4 Design and operation of local distribution vehicles There will be few real advances in the design of chilled distribution vehicles until there is a firm understanding of the interaction between theThe uninsulated vehicles were mostly 10cwt (0.5 ton) delivery vans, with no partition between driver and load. Since that time the intensifying demand from legislation and retailers for lower delivery temperatures, has put increasing pressure on fleet operators to improve temperature control. However, there are substantial difficulties in maintaining the temperature of chilled foods transported in small refrig￾erated vehicles that conduct multi-drop deliveries to retail stores and cater￾ers. The vehicles have to carry a wide range of products and operate under diverse ambient conditions. During any one delivery run, the chilled product can be subjected to as many as fifty door openings,where there is heat ingress directly from outside and from personnel entering to select and remove product.The design of the refrigeration system has to allow for extensive dif￾ferences in load distribution, dependent on different delivery rounds, days of the week and the removal of product during a delivery run.The ability of a refrigeration system to respond to sudden demands for increased refrig￾eration is often restricted by the power available from the vehicle. All these problems combine to produce a complex interactive system. In the UK, current sales of chilled foods are expanding. The overall market worth for chilled foods increased from £5.8 billion in 1992 to £6.2 billion in 1993. In the meat industry the traditional range of pies, pasties, sausages and cooked meats has been rapidly developed with the addition of fermented meats, restructured products, Kievs, salads, stir fry products, and vegetarian burgers and rissoles. Traditional meat product manufactur￾ers are now aiming to extend their range of products to include items such as gourmet-style meals without artificial colours, flavours or preservatives. Retailers are discovering that considerable quality and economic advan￾tages can be derived from maintaining chilled products at temperatures far closer to their initial freezing point. Increasingly, fleet operators will be forced to deliver chilled foods at temperatures between 0 and 2 °C. 9.3.4 Design and operation of local distribution vehicles There will be few real advances in the design of chilled distribution vehicles until there is a firm understanding of the interaction between the 198 Meat refrigeration Table 9.4 Types of road vehicle investigated in Meat Research Institute (MRI) Survey (1970–71) System No. of cases Mechanical 9 Liquid nitrogen 2 Insulated, non refrigerated 18 Uninsulated 7 Source: Cutting and Malton, 1972