GB2196830A - Storing pre-cooked food for vending - Google Patents

Abstract

A method of processing pre- cooked food for consumption in individual containers comprising freezing the food in the containers, storing the food in a frozen condition, thawing the containers to a chilled condition, storing the chilled containers in a food vending apparatus and then delivering chilled containers to an oven from which the containers are delivered to the consumer. <IMAGE>

Description

SPECIFICATION Method of processing food This invention relates to a method of processing pre-cooked food for consumption in individual vendable containers. The invention is particularly concerned with the dispensing of heated food from a vending machine.

The storage and distribution of food in individual vendable containers involves the.prob- lem that the food must be deep frozen if it is to survive long term storage, yet it can only be transported to, and stored in, a vending machine in a thawed and chilled condition if the period required to reheat it is kept to a minimum within the limit of ovens associated with vending machines; moreover, chilled food generally deteriorates after a period of five days from thawing.

According to the invention we provide a method of processing pre-cooked food for consumption in individual, vendable, ovenproof containers, comprising placing the precooked food in the containers; deep freezing the containers of food, storing the containers deep frozen in long term storage; thawing the containers to a chilled condition, storing the containers in the chilled condition in a refrigerated compartment of food-vending apparatus for not more than five days from thawing and, on demand, transferring a container from said compartment into an oven associated with the food-vending apparatus where it is heated and subsequently dispensed to a customer with the food therein ready for consumption.

This method allows the food to be stored in long term storage until required in the vending machine, then thawed for transport to the vending machine and stored for subsequent sale at the same, chilled, temperature from which it may easily be reheated for consumption.

The speed at which the temprature of the food may be changed, for deep freezing or thawing, is also very important, since it is clearly desirable to make the deep freezing and the thawing processes as short as possible. The thawing process must be fast in order to be able to respond quickly to demand, and the deep freezing must be fast in order to minimise the deterioration of the food as a result of the penetration of the food cell walls by the ice crystals formed.

Preferably, during thawing, the whole of the outer surface area of each container is exposed to fluid flow, the transfer of heat between the fluid and the containers thus proceeds at the maximum possible rate, thus minimising the time taken for thawing.

In order that the invention may be better understood, a preferred example thereof will now be described with reference to the accompanying diagrammatic drawings: Figure 1 is a perspective view of an empty platen; Figure 2 is an elevation of a vendable container; and Figure 3 is a front elevation of a trolley for supporting several platens each identical to that shown in Fig. 1.

With reference to Fig. 1, a platen 1 has a main body 2 of rectangular shape, in which are formed eight apertures 3 in two rows of four. End flanges 12 and side flanges 13 form a continuous peripheral edge to the platen 1, and have the same vertical dimension as a central, longitudinal rib 10, a central, lateral rib 8 and two further, intermediate lateral ribs, not shown. The ribs and side and end flanges strengthen the frame of the platen, and in particular serve to strengthen the webs between the apertures 3.

Two feet 4 are provided at each end edge of the platen 1, the feet 4 being vertical extensions of the end flanges 12. Above each foot 4, an upstanding foot support 5 is provided, each foot support 5 having a generally horizontal foot support surface 6 connected to a three-sided vertically extending wall 7 whose longest side faces inwards of the foot support. The foot support surface 6 and the corresponding vertical wall 7 are together complementary in shape to the foot 4, to enable vertical stacking of the platens.

The platen 1 is an integral plastics moulding and may be formed of polypropylene containing a suitable pigment.

The purpose of the platen 1 is to support vendable food containers 11. Such containers may be of the construction shown in out PCT Patent Application No. GB87/00697 the disclosure of which is incorporated herein by reference. Each container 11 has a rectangular shape, in plan view, appropriate to the shape of the apertures 3 in the platen 1 as described below. The container is in the form of a shallow tray with tapering side walls, the lateral and longitudinal dimensions of the tray widening upwardly. The tray has a lid 1 1A secured to an outwardly extending peripheral flange 11B, which is horizontal.

The containers 11 extend through respective ones of the apertures 3, and are removably supported on the main body 2 of the platen 1 by means of their peripheral flanges 11 B which rest on the edges of the apertures 3.

The containers are thus supported vertically, and are constrained against horizontal movement by the edges of the apertures 3.

The undersides of the feet of each platen lie in a common base plane which, when the platens are stacked, coincides with a common foot support plane in which the foot support surfaces 6 of the immediately subjacent platen lie.

A stack of several filled platens, i.e. full of containers 11, may readily be carried with the containers resting on the edges of the corresponding apertures. A narrow vertical gap is provided between vertically adjacent pairs of the containers.

With reference now to Fig. 3, a trolley 20 is provided for transporting several platens 1 supporting several containers 11 in a threedimensional matrix. The trolley has a frame consisting of two left hand corner posts 21 and two right hand corner posts 22, connected by a roof plate 25 and a floor plate 26. The trolley is generally in the shape of one of the platens 1, in plan view. Twenty pairs of horizontal rails 23, of L-shaped crosssection, are provided for supporting twenty platens 1. The left hand rail of each pair is supported between the corner posts 21 on the left hand side of the trolley, and the right hand rail of each pair is supported, at the same height, between the corner posts 22 on the right hand side of the trolley. The rails are spaced horizontally by a distance substantially equal to the length of a platen 1, and the feet of the platen are slidable along the rails.Sufficient vertical clearance is provided between vertically adjacent pairs of rails to allow the foot supports 5 to slide unimpeded by the rails for the immediately superjacent platen.

The vertical distance between adjacent rails is such that, when the trolley is filled with containers, vertically-adjacent containers are spaced by a vertical gap, the gap however being sufficiently narrow as to prevent the lower containers from being jostled of their apertures.

The four vertical faces of the trolley are generally open to the surrounding atmosphere, the ends of the rails 23 terminating at a front face 40 of the trolley through which the platens enter and leave the trolley. The platens are prevented from sliding out of the trolley at the back face thereof by means of a vertical flange 24 extending from the left hand rear corner post 21 and serving as a stop at the ends of the rails 23 at the left hand side of the trolley.

The platens 1 may be locked into the trolley by means of a vertical locking bar 28 hinged to the front right hand corner post 22, diagonally opposite the flange 24. The locking bar 28 thus pivots about a vertical axis at the corner of the trolley, between a locking position 28 at which it prevents the platens from sliding out of the trolley, and a position 28' (shown in broken lines in Fig. 6) at which it allows the platens to be moved in and out of the trolley. The locking bar 28 is hinged by means of an upper hinge 29 and a lower hinge 30 which allow the locking bar to rise and fall vertically. This enables a latching hook 31 connected to a mid-point of the locking bar 28 to be latched over a horizontal latching bar 32 which extends between the front corner posts 21, 22 in the front face 40 of the trolley.In the locking position of a locking bar 28, the latching hook 31 engages the latching bar 32, preventing pivotal movement of the locking bar 28. The locking bar 28 may be pivoted to its open position 28' only by raising the locking bar in its hinges 29, 30.

The trolley is provided with four bogies 27 with wheels for easy transport.

Several such trolleys 20 may be arranged together with their vertical side faces in engagement, either during transport or storage, or during a heating or cooling process in an air flow chamber, as described in greater detail below. In such close configuration, the roofs 25 and the floors 26 join to form a common roof and a common floor, the internal spaces of the trolleys also joining to form a tunnel.

The handling, transport and heat treatment of food containers will now be described in greater detail.

Pre-cooked food is dispensed into the containers 11, which are of a material, such as polymer-coated paperboard, which is ovenproof and microwave ovenproof, i.e. is transparent to microwave radiation. The containers are then closed and placed in platens 1.

The filled platens are then stacked in trolleys 20, as shown in Fig. 3, so that there is a substantial vertical gap between each vertically adjacent pair of containers 11. The assembled trolleys are then transported to a refrigeration air flow chamber (not shown). As described above, with reference to Fig. 3, several filled trolleys 20 are packed closely together in the chamber, and they together define a "wind tunnel" with open ends. The pre-cooked food is then frozen in the containers to a temperature of - 1 8 degrees C. by directing a flow of air at -40 degrees C. from one end of the wind tunnel to the other end, the flow being recirculated above the roofs 25 of the trolleys.

Because the containers 11 are supported with substantially all their external surface area exposed to the air flow, the freezing process occurs rapidly. The air flow is preferably at a rate of five metres per second.

When the containers 11 have reached the desired temperature of - 18 degrees C., the trolleys are left in long term storage, either in the chamber or in a separate compartment, where they are maintained at this temperature.

Other arrangements may be made for deepfreezing the containers and they may then be placed in the trolleys for thawing to the chill temperature.

When they are required for distribution, the food containers 11 are thawed in an air flow chamber, usually a different chamber from that responsible for the refrigeration process, by directing a flow of air at between 2 and 3 degrees C., again at five metres per second, at the containers, with the trolleys closely packed together as described above. This process is continued until all the containers reach the desired final temperature of between 2 and 3 degrees C. The time taken for the freezing process and the thawing process is in each case approximately twelve hours.

The trolleys are then transported to outlets having vending machines. The food containers may be stored for up to five days chilled at the refrigerated temperature of 2 to 3 degrees C. The food containers are dispensed from automatic vending machines having associated microwave ovens, the platens are removed from the trolleys and the containers removed from the platens and loaded into the refrigerated storage of a vending machine. Such a machine may be of the construction shown in European Patent Application No. 86901110.6, the disclosure of which is incorporated herein by reference. The refrigerated food containers are maintained chilled at the temperature of 2 to 3 degrees C. in the vending machine, until such time as they are required to be dispensed to a customer. Each successive individual food container is then fed automatically to a microwave oven within the machine, reheated, and dispensed to the customer with the food therein in a ready-to-eat state.

Claims (6)

1. A method of processing pre-cooked food for consumption in individual, vendable, oven-proof containers, comprising placing the pre-cooked food in the containers; deep freezing the containers of food, storing the containers deep frozen in long term storage; thawing the containers to a chilled condition, storing the containers in the chilled condition in a refrigerated compartment of food-vending apparatus for not more than five days from thawing and, on demand, transferring a container from said compartment into an oven associated with the food-vending apparatus where it is heated and subsequently dispensed to a customer with the food therein ready for consumption.

2. A method according to Claim 1, wherein the containers are deep frozen by directing a flow of air onto the containers at substantially -40 degrees C, the containers being deep frozen and stored deep frozen at substantially -18 degrees C.

3. A method according to Claim 1 or Claim 2, wherein the containers are thawed to a temperature of substantially 2 to 3 degrees C.

by directing a flow of fluid onto the containers, the velocity of flow of the fluid being substantially five metres per second.

4. A method according to Claim 3, wherein during thawing the containers are stacked with spaces between adjacent containers for the fluid flow and are supported such that substantially the whole outer surface of each container is exposed to the fluid flow.

5. A method according to Claim 4, wherein during thawing the containers are supported in at least one trolley each supporting verticallystacked removable platens containing several of the containers, the platens having apertures, corresponding in shape to the containers, the edges of the apertures removably supporting flanges on the containers with a minimal area of contact.

6. A method of processing pre-cooked food for consumption, substantially as described herein with reference to the accompanying drawings.