One of the critical problems faces the catering stuff is keeping food hot until served to customer or hospital patient. If food is allowed to cool down to below 70 – 75 °C, it will not only lose good taste, but also it will allow harmful micro-organism to grow, (see Storage equipment, to know more about food storage temperatures). Ordinary (un-covered) serving tray can not be used for long transportation such as in hospitals, where the meal will be cooled down before eaten. The following trays (shown below) are designed to keep food hot and are commonly used in hospitals and similar food distribution systems. Before selecting your tray, you have to consider the following

selection factors:

·       Material; food approved heat resistant polymer with environment friendly components & insulation.
·       Size & shape should match serving plates and transport trolleys. Also size is preferred to be according to an international sizing system (e.g. Gastronorm or Euronorm size – see Gastronorm Sizing system) to be sure that tray will be handled easily in all equipments in kitchen (e.g. dishwasher, shelves, trolleys, etc).
·       Type (insulated, heated …see below).
·       Should be stacked easily.
·       Should be dishwashable (in a dish washing machine).
·       Available manufacturer accessories should be considered such as marking system, carrying trolleys & baskets, plates, etc.
·       See next examples
Note: All shown below trays are manufactured by “Menu-Mobil” – Austria.
Insulated trays; Fig.14.2.32 shows an insulated tray suitable for serving of hot & cold foods (insulation minimize heat transmission between hot & cold foods), injected foam insulation, tray cover, recesses govern plates to avoid spoilage of foods, easily stacked, can be washed in a dishwasher, model (Universal).



Fig.14.2.32 Insulated tray (with cover) – model Universal – MENU-MOBIL – AUSTRIA 

Fig.14.2.33 shows tray carrying basket for easy transportation of small quantities of trays. Fig.14.2.34 shows different tray marking systems either by  writing on a card inserted on a card holder or by different color magnetic tabs for different menus (e.g. in a hospital there are several menus according to patient such as low salt food, cold food, liquid food, diabetics food, etc).
Fig.14.2.33 Tray basket – MENU-MOBIL – AUSTRIA
Fig.14.2.34 Tray marking systems – MENU-MOBIL – AUSTRIA

Electrically heated trays; Fig.14.2.35 shows heated tray with 2 or 3 heating compartments each with separate independent thermostat control (for soup dish & main coarse). Tray requires 12 Volts power source can be obtained from a rechargeable battery, available from the same manufacturer. Tray can be transported on baskets see Fig.14.2.33 or in trolleys & vehicles. This type of trays is suitable for extra long transportation either in-house or outside.


Fig.14.2.35 Heated tray –  MENU-MOBIL – AUSTRIA
Electric induction heated trays; This is the latest technology in heating of transported food (see Cooking equipments, to know more about induction heating). Induction heated tray (Fig.14.2.37 & 38) is composed of insulated tray, in addition to induction unit (Fig.14.2.39). This tray requires special dishes as shown in Fig.14.2.40, bottom coated dishes are used for hot foods while uncoated used for cold foods, salads, fruits, etc.


Fig.14.2.37 Induction heated tray – MENU-MOBIL – AUSTRIA


Fig.14.2.38 Hot & cold dishes on tray – MENU-MOBIL – AUSTRIA
Fig.14.2.39 Electric induction unit – MENU-MOBIL – AUSTRIA

tray8                         tray7

Bottom coated for hot                 Uncoated bottom for cold

Fig.14.2.40 China dishes – MENU-MOBIL – AUSTRIA