Abstract: A disposable microwave browning and crisping package having a flat substrate and a microwave reactive layer affixed over one surface of said substrate, the microwave interactive layer, when subjected to microwave energy, converting microwave energy to heat in an amount sufficient to brown and crisp food in heat transfer relationship has at least one aperture to allow gases and vapors generated from cooking foods such as large pie crusts to traverse said laminate thereby allowing the food product to remain in close proximity to the reactive heater resulting in improved browning and crisping.

Abstract: A microwave potato baking stand and method for baking potatoes is provided. The stand consists of an upstanding spike supported by a base. A potato is impaled on the spike substantially towards the tip, whereby it may efficiently receive microwave energy and provide a more thorough cooking. As the pulp of the potato softens to the desired consistency from cooking, the potato slides down the spike to indicate a fully cooked potato. The stand may be modified to provide additional visual cues, such as a trigger released indicator arm.

Abstract: A package for heating food in a microwave oven is disclosed. The package includes metal shielding or other metal components which cause a gain in electric field strength which is greater than 3. The present invention also involves low load microwave environments where the electric field strength is greater than 10 volts per centimeter. A rigid, dimensionally stable dielectric support is provided in close proximity to a conductive sheet, being spaced less than 0.5 inch from the conductive sheet. The dielectric support is composed of material selected to avoid failure of the dielectric support in high electrical fields which may exist near the conductive sheet during microwave irradiation. The dielectric support material has a dielectric loss factor less than 0.005, and a failure temperature greater than 101.degree. C. The present invention relates to intrinsically nonarcing packages.

Abstract: There is provided an improved disposable receptacle with a self-supporting configuration for combined baking and cooking of a generally flat food article, such as pizza having a given thickness, in a microwave oven, which receptacle is constructed from a sheet of microwave susceptor stock surrounding the food article and comprising an outwardly exposed, dielectric support layer, such as paperboard, and an inwardly facing heating layer of microwave interactive material allowing passage of microwave energy as it is heated thereby and further including a lower flat portion for supporting the food article during microwave heating.

Abstract: A container for holding a body of material such as foodstuff to be heated in a microwave oven, including a dielectric lid and/or other dielectric wall structure with at least two ontiguous dielectric wall portions of respectively different electrical thickness for cooperatively modifying the microwave electric field patterns that would obtain in the body during such heating if the lid and/or other dielectric wall structure were of uniform electrical thickness or were absent. At least one of the portions, preferably the portion of higher electrical thickness, may be so constituted as to undergo a change in dielectric constant during the microwave heating, thereby to alter the heating distribution in the body as heating proceeds.

Abstract: A food vessel comprising a heating element for use in a household microwave oven is provided. The heating element is made of paper and a dielectric material such as aluminum foil. When bread dough or so forth is put into the vessel to be heated in the microwave oven, temperature of the heating element rapidly increases to a desired value and the bread dough rises while remaining in contact with the heating element. A uniformly browned loaf of bread of any desired configuration can thus be produced.

Abstract: A cooking kit which is useful in cooking food in a microwave oven chamber and also can be employed in thermal ovens and on a cooking range. The kit includes an imperforate outer metal pot, a perforated inner metal pot which nests in the outer metal pot. The perforated bottom surface of the inner metal pot is spaced apart from the bottom surface of the outer metal pot to provide a metal shielded drainage collection chamber between the two pots. A microwave transmissive cover fits on the nested metal pots and forms a cooking chamber which includes at least the perforated inner metal pot. The outer metal pot is preferably coated with porcelain enamel which functions as a thermal and electrical insulator.

Abstract: An apparatus and method for heating a food product in the presence of a radiant energy source includes a collector having a plurality of radiant energy reflective cells enclosed in a radiant energy transparent material. The cells are formed by a number of tabs that collect the radiant energy incident on the collectors and form a radiant energy field to uniformly heat the food product. The tabs can be manufactured from a material having a graduated thickness or gradient. The distribution of power within the collector cells is controlled by varying the number or size of the cells as well as the shape, angle or position of the tabs physically or automatically. The cells can be formed on a ceramic substrate, which can include a ferrite like coating, such as tin oxide.

Abstract: A paperboard container assembly for the microwave cooking and browning of food. The assembly is defined by an outer carton which surrounds a separate elongated tray. The tray is formed of a unitary blank of paperboard, a microwave interactive material and a polymer coating. The interactive material browns and crisps the food surface where contacted. The ends of the tray carry elongated, hollow feet to both support the tray bottom in vertially spaced relation to the carton bottom and to prevent shifting of the tray relative to the carton. Openings along the tray sidewalls and hollow feet prevent both scorching or burning of the paperboard and delamination of the polymer coating due to localized heat build-up.

Abstract: A package for holding and microwave cooking of food comprising two or more food holding units, each having the shape of a generally rectangular box with opposed, opens ends and comprising, a first panel having a microwave absorbing heating surface facing the interior of the package, a second panel located opposite, spaced from and substantially parallel to the first panel and having a microwave absorbing heating surface facing the interior of the package, and a pair of substantially parallel side wall panels of approximately equal height connecting the first panel and the second panel, each of the side wall panel having an opening between its ends, wherein each food holding unit has the same orientation as the others and is joined to at least one adjacent food holding unit at a weakened separation line that encircles the packages in a plane substantially perpendicular to the first and second panels.

Abstract: Batter-based baked goods, such as brownies, are produced by subjecting a microwave-transparent pan containing unbaked and non-frozen batter to microwave energy in a microwave oven. The oven has a klystron transmitting energy at a frequency having a wave length, in inches, equal to .lambda.. The pan, which is free of sharp corners, has bottom and side walls and an open top for receiving the batter, and has its bottom wall and thus the batter spaced apart from the interior bottom wall of the oven by a microwave transparent spacer means. The bottom and side walls confine the batter in the pan to predetermined height, width and length dimensions such that each dimension is a multiple of the quarter wavelength .lambda./4 of the frequency of the microwave energy applied to the batter; preferably such that one dimension, in inches, is a .lambda./4, where A is an odd integer from 1 to 15, another one of the dimensions is B .lambda./4 where B is an even integer from 2 to 12, and the remaining dimension is C .lambda.

Abstract: A medium formed by a mixture of polymeric binder with conductive and semiconductive particles that can be coated or printed on a substrate to convert electromagnetic radiation to heat without arcing and produce increase heating of foods. Conversion efficiency can be controlled by the choice, thickness, pattern and amount of materials used in the medium. The medium can be used repeatedly without burn out. The conductive particles are typically aluminum, copper, zinc and nickel and the semiconductive particles are typically carbon, titanium carbide and zinc oxide.

Abstract: A method of making a food product for heating in a microwave oven by use of a waveguide containing one or more food products therein. By the proper control through selection and/or varying certain properties of the food product and the container, controlled disposition of microwave power within the food product can be accomplished so that the food product can follow a desired time/temperature relationship and achieve a final desired temperature after exposure to microwave radiation.

Abstract: A microwave popcorn popper has a generally cylindrical open topped container with a snap on domed cover. A raised downwardly and outwardly tapering frusto conical partition is provided in the container, above an interior flat circular floor of the container. An elongated cylindrical tube extends through a central circular aperture in the partition and has a bottom end resting on the flat circular floor. An upwardly opening conical receptacle is provided in the bottom portion of the tube for holding a quantity of unpopped corn and oil. A circular cap over and open top end of the tube is formed by two semi-circular plates connected by a central hinge. In use, a quantity of unpopped corn is placed in the conical receptacle and the entire unit is placed in a conventional microwave oven. The conical receptacle concentrates the corn kernels at the central focal point of the microwaves within the oven.

Abstract: A closed-loop control for sensing the completion of popcorn popping in a microwave oven and automatically shutting down the oven. A sensor is acoustically coupled to the microwave oven cavity and provides an electrical signal to an amplifier and filter. The amplified and filtered signal is processed by a pop detector which includes an integrator and shut-down command generator responsive to a decreasing rate of popping to shut the oven off. The integrator provides a pre-pop timer function to maintain the oven on until popping commences.

Abstract: A microwave cooking utensil useful for assuring destruction of Salmonella or other harmful bacteria present in cooking liquids during the cooking of poultry including an outer container made of microwave reflective material, a microwave transmissive steam-confining cover enclosing the outer container, and an apertured rack for supporting, essentially in contact thereon, a food product. The rack is made of heat-conductive, microwave-reflective material and includes a support to hold the rack above the bottom surface of the container so that the rack and the bottom surface define a chamber to receive cooking liquids. The rack has a first set of apertures proximate to its periphery large enough, and with a total area large enough, to permit passage therethrough, during the normal poultry cooking cycle, of sufficient microwave energy to pasteurize any Salmonella bacteria present in the cooking liquids.

Abstract: A microwave oven of a type equipped with a turntable inside its heating chamber has indented parts formed on the walls of the heating chamber. A rack is supported over the turntable by supporting members which are attached to these indented parts. Each supporting member has a part which is rotatable around a horizontal axis such that it can be unfolded to protrude into the chamber or folded inside the indented part without protruding into the chamber.

Abstract: A metal tray has its inner and outer surfaces coated with a plastic material. Within the tray is a first susceptor unit which includes a layer of corrugated paperboard composed of A-flutes secured to the underside of a substrate having a metallized foil secured to its upper side. A food item to be heated is supported on the first susceptor unit. A second susceptor unit overlies the food item, the second susceptor unit having a downturned flange inserted between one side of the tray and one side of the food item.

Abstract: An improved metallic cooking utensil suitable for use both in stovetop cooking such as frying and in a microwave oven is disclosed. The utensil features a bowl member formed of a single piece of stainless steel having a relatively square cut-off edge, that is, without a rolled-over edge or other complex edge detail. The upper portion of the disk member forms a circumferential flange which is extended at least two points to receive handles. The handles are formed of a microwave-transparent polymer material, and are affixed to the extended portions of the flange by rivets extending through square holes formed in the flange extensions. The bowl defines a relatively broad radius between its bottom portion and the upper flange, and may have a heat conductive element plated onto or affixed to its bottom for improvement of its heat conducting characteristics.

Abstract: A container useful in microwave heating of foods comprises a substrate with a titanium nitride film on at least a portion of the substrate. The substrate is substantially microwave transparent except where coated with the titanium nitride film. The film is adapted to absorb microwave energy. The film thus becomes heated and transfers heat to foods when adjacent the film. This heat transfer provides crisp heating of foods, such as fried chicken, french fries and the like.

Abstract: A food package is provided wherein the accommodated food product, while remaining in the package, may be heated or cooked in a microwave oven. The food product has at least one predetermined portion thereof which requires enhanced heat while the product is being heated or cooked in the oven. The food package includes a container formed of heat resistant material which is pervious to the microwaves. A surface of the container is provided with an area which is in proximity to the predetermined portion of the food product requiring the enhanced heat. A metallized ink, consisting of metal particles suspended in an ink-like substance, is deposited on the surface area of the container. Thus, when the metallized ink is exposed to the generated microwaves, the required enhanced heat is produced in the vicinity of the surface area.

Abstract: A container for holding material such as foodstuff to be heated in a microwave oven, including an open-topped tray and a lid for covering the tray to form a closed cavity, wherein at least one surface of the container has one or more electrically conductive plates and/or microwave-transparent apertures for generating a microwave field pattern having a higher order than that of the fundamental modes of the container, such that the field pattern so formed propagates into the contained material to thereby locally heat the material.

Abstract: A medium formed by a resin binder with conductive and semiconductive particles that can be coated on a substrate to convert electromagnetic radiation to heat. Conversion efficiency can be controlled by the choice and amount of materials used in the medium, which can be used repeatedly without burn out.

Abstract: Several package embodiments are illustrated. In two embodiments, a panel constitutes an extension of one wall of a flexible bag having therein a susceptor pad. Only a portion of the panel is adhesively secured to the end wall, there being a second portion constituting a flap that extends freely from the bag so that the flap remains quite cool when the package is heated in a microwave oven, even though the bag itself becomes quite hot. The third embodiment involves an individual panel having one portion thereof adhesively secured to an end wall of the bag and a second portion constituting a flap that extends upwardly from the end wall so that the flap remains relatively cool and can be grapsed with a person's fingers to effect safe handling of the bag after being heated in the microwave oven.

Abstract: A container (2) for heating popcorn or other types of particulate food items in a microwave oven formed from a single blank having a bottom panel (4) coated with a microwave interactive material (26) adding heat to particulate food items such as popcorn kernels and configured so that each particulate food item placed into the container (2) for heating is spaced, on average, no more than the average diameter of one such food item away from the microwave interactive layer. The container is formed for shipping in a triangular wedge shape and for expansion to a trapezoidal box shape for use within a microwave oven for heating of the particulate food items.

Abstract: A package for microwave heating of food products includes a multi-layer sheet material having a first paper layer defining an exterior portion of the assembled package. A metallized polyester is laminated to the paper layer and defines the interior portion of the assembled package. A plurality of pinholes extend completely through the sheet material. Peripheral regions of the sheet material are left free of any pinholes to receive an adhesive for securing the sheet material to itself and form the completed package. Absence of the pinholes inhibits passage of the adhesive to the interior of the assembled package.

Abstract: A container constituted of a microwave transparent material for the heating or cooking of foods or comestibles through the intermediary of microwaves at a high degree of efficiency and with an enhanced temperature uniformity. The container base is configured in a manner to produce generally wavilinear or undulating bottom wall and side wall configurations which will disperse the food or comestible within the container to an optimum extent so as to increase the heating and cooking efficiency thereof, and to provide a more uniform temperature distribution throughout the container contents, thereby enabling the rapid and even heating and/or cooking of the food by microwave energy.

Abstract: A microwavable package for storing and cooking a food product such as bacon, includes an absorbent bed enclosed within a sealed plastic sleeve. During microwave cooking, the corrugated bed collects oil or grease released by the food product and maintains a portion of the food product in contact with the collected oil or grease to impart a pan-fried quality to the cooked food product. Vents in the sleeve permit the controlled escape of water vapor so that the sleeve billows away from the food product during cooking. An inert, oxygen-free atmosphere is contained within the package, and a plurality of the microwavable packages are enclosed in a sealed outer barrier wrap prior to their removal for cooking.

Abstract: A rice cooker for preparation of shaped foods of rice in a microwave range is made of microwave permeable synthetic resin such as polypropylene and internally provided with mutually separate confined spaces of a fixed capacity and adapted for accommodating rice with water. As the rice cooker containing uncooked rice with water is heated in the microwave range, compression acts on the boiled rice due to pressure contact of the boiled rice swelled with water with walls defining the spaces and the boiled water is automatically shaped in the spaces. Absence of direct contact of the rice with user's hand during the process enables preparation of shaped foods of rice such as rice balls without any keen pain and blemish on the hands.

Abstract: A film package is provided for containing, heating, and browning or crispening a food item, which has a microwave susceptor-containing film and an insulating layer between regions of the film laden with susceptor which are in proximity with each other. The insulating layer prevents the susceptor laden areas in proximity with each other from overheating.

Abstract: A food container for use in a microwave oven is disclosed. The container contains a plurality of food substances, and employs a metal shield to shield at least one of the food substances from microwave radiation. Arcing and other problems associated with the use of metal shielding are avoided by proper selection of the geometry of the metal shield. The metal shield is preferably looped in a manner which provides some electrical inductance, and the ends of the metal shield are overlapped and separated by a dielectric material to provide some electrical capacitance. The geometry of the shield is selected so that the inductance and the capacitance in effect form a "tuned circuit" which minimizes problems associated with resonance and which eliminates arcing.

Abstract: Bowl-shaped plastic dish for use in microwave ovens, the dish having a two-part structure composed of an inner shell and an outer shell, each shell having a circumferential, laterally projecting edge web, the inner and outer shells being spaced from one another to define a space containing air, and the shells being welded or glued to one another in the region of the webs to seal the air space.

Abstract: A stackable plate arrangement (10) for microwave ovens (100) wherein the arrangement (10) comprises a plurality of apertured plate units (11) that are adapted to be operatively connected together at different heights by a plurality of support units (12) such that multiple food receptacles (200) may be suspended on different tiers within a microwave oven (100).

Abstract: A combination of a mass produced frozen entree type foodstuff, such as a pot pie, formed from a precooked, lossy material filler food having a preselected depth and covered with a layer of uncooked dough and an appliance for transporting and reconstituting this pot pie in a microwave oven wherein the appliance comprises a dish-shaped receptacle formed of a microwave impervious foil material with a cavity for the foodstuff and a peripheral rim whereby the filler material within the cavity is shielded from direct microwave exposure except through the dough layer and a flat, self-sustaining generally rigid microwave susceptor sheet with an outer shape generally matching the preslected shape of the rim on the receptacle wherein the susceptor sheet is supported on the dough in parallel, heat conducting relationship with the upper surface of the dough and is spaced from the rim by the dough. The susceptor sheet includes a thin metallized layer of plastic film laminated to a paperboard.

Abstract: A rice gruel cooker suited for heating in a microwave range includes a bowl, a perforated rice container placed in the bowl and having a space for accommodatng rice, and a lid held above the top end of the bowl. During heating, boiled water circulates actively through the space containing the rice and boils the rice uniformly without production of cores in rice particles despite quick heating in the microwave range. Specified lid position well prevents overflow and/or scattering of boiled water during cooking.

Abstract: The present application is directed to a package material for microwave cooking which is obtained by integrally laminating a microwave heating element, which generates heat when irradiated with microwave, to a base material to form a sheet; and providing, on the sheet, many slits in the form of broken lines, in parallel, and in alternation between the adjacent ones.

Abstract: A container for containing a material to be heated in a microwave oven, having at least one stepped structure protruding into or out of the container from a surface thereof, this structure including a side wall or side walls that define boundary conditions that generate a microwave field pattern within the container having a higher order than that of the fundamental mode of the container.

Abstract: Disclosed are improved ceramic compositions which are useful in the formulation and fabrication of microwave susceptors for disposable packages for the microwave heating of food items and to such articles themselves. The compositions include certain metal salts as time/temperature profile moderators in addition to novel microwave absorbing materials and a binder. Certain metal salts can be used to dampen or lower the final temperatures reached upon microwave heating the ceramic compositions. Other metal salts can be used to increase or accelerate the final temperatures reached upon microwave heating. The microwave absorbing materials comprise ceramics with neutral lattice charges such as clays, talc, kaolin, silicates, aluminosilicates, sodium metasilicate, alumina and mixtures thereof. The compositions provide good heat generation and a predeterminable upper temperature limit. The materials are common and inexpensive.

Abstract: A disposable food receptacle for use in microwave cooking is disclosed which includes a provision to brown the exterior of the food in the receptacle. A thin layer of an electrically conductive material, such as an elemental metal is incorporated into the receptacle on the food contacting surfaces thereof, so that the conductive layer will become heated by the microwave radiation and will, in turn, brown the exterior of the food in the receptacle. The conductive layer is formed as an extremely thin film deposited on a substrate protective layer by a process of vacuum vapor deposition.

Abstract: A mixing attachment for stirring sauces, foods, mixtures or the like in a microwave oven. The mixing attachment includes a vertical mixing arm, a stationary blade attached to the bottom of the arm, and a cross beam, which is fastened to the top of the vertical mixing arm. The cross beam is secured to the walls within the microwave oven. One way to implement the mixer is to extend the arm downward into a cooking dish. The cooking dish contains food and rests on a turnable. When cooking food, the turntable rotates causing the food to be mixed by the stationary blade. In addition, the blade may be made to move up and down by the rotating turntable through a series of cams and a drive wheel.

Abstract: The present invention provides a microwave heating sterilizer provided with a mechanism for turning over a retainer made from a material being permeable to microwave and which contains a "material to be sterilized" in a cavity irradiated with microwave therein supporting shafts extend from positions determined at point symmetry with respect to the center of the retainer on the opposite ends thereof, and turning-over parts each having a higher slide surface than the other part thereof on the midway of a guide which conveys the retainer and a turning-over groove on the midpoint thereof are provided.

Abstract: A collapsible package for use in surface heating of food by microwave energy comprises first and second sling enclosures. Each sling enclosure comprises a pair of parallel, opposed, substantially rectangular wall panels, the ends of which are joined by collapsible bridge panels. The bridge panels are movable between a collapsed position in which the wall panels lie against each other and an expanded position in which the wall panels are held in spaced relation to each other. The second sling enclosure is joined to the first sling enclosure at a center fold line between adjacent wall panels of said first and second sling enclosures. A generally rectangular strip of thin, flexible material capable of converting microwave energy into heat is affixed between the two opposed side walls of the first and second sling enclosures that are not connected at the center fold line. One of two opposed edges of said strip if affixed to each side wall.

Abstract: Disclosed are improved ceramic compositions which are useful in the formulation of microwave susceptors and to the susceptor articles fabricated therefrom for disposable packages for the microwave heating of food items. The compositions include a novel microwave absorbing material and a binder. The novel microwave absorbing materials comprise selected ceramics in both their native and amphoteric forms. Such ceramics are those with residual lattice charges or an unbalance of charge in the fundamental framework or layers such as vermiculite, bentonite, hectorite, selected micas including Glauconite, Phlogopite and Biotite and mixtures thereof. These ceramics are activated to their amphoteric form by treatment with either acids or bases. The compositions provide good heat generation and a predeterminable upper temperature limit which is higher in the amphoteric form than in their native form. The ceramic materials are common and inexpensive.

Abstract: In an automatic cooking of cake, a gas sensor and a weight sensor are used to determine a total heating time. The initial weight of a food item (cake) is measured by the weight sensor, and a time (T.sub.W) proportional to a detected value of the weight sensor is determined. The amount (.DELTA.H) of change in humidity level until an arbitrarily chosen timing is detected by the gas sensor, and a time (T.sub.(.DELTA.H)) proportional to a detected value of the gas sensor is determined. These times (T.sub.W) and (T.sub.(.DELTA.H)) are added together to determine a total cooking time. With this arrangement, regardless of the kind and amount of cake and the shape of a vessel, the automatic cooking capable of giving a fine finish can be accomplished merely by selecting a single auto-key called a cake key.

Abstract: A container for holding a body of material to be heated in a microwave oven, the container having at least one surface provided with a structure for generating within the container a microwave energy mode of a higher order than that of the container fundamental modes, wherein the mode generating structure has a periphery formed with a multiplicity of protuberances distributed around its perimeter for diffusing the heating effect of the higher order mode microwave energy.

Abstract: Disclosed are ceramic compositions which are useful in the formulation and fabrication of microwave susceptors for disposable packages for the microwave heating of food items. The compositions include a novel microwave absorbing material and a binder. The novel microwave absorbing materials comprise ceramics with neutral lattice charges such as clays, kaolin, talc, silicates, alumina, aluminosilicates and mixtures thereof. The compositions provide good heat generation and a predeterminable upper temperature limit. The materials are common and inexpensive. Preferred compositions additionally include a temperature profile moderator which can be common salt.

Abstract: Disclosed are improved ceramic compositions which are useful in the formulation of microwave susceptors and to the susceptors fabricated therefrom for disposable packages for the microwave heating of food items. The compositions include certain metal salts as time/temperature profile moderators in addition to a novel microwave absorbing material and a binder. Certain metal salts can be used to dampen or lower the final temperatures reached upon microwave heating the ceramic compositions. Other metal salts can be used to increase or accelerate the final temperature reached upon microwave heating. The microwave absorbing materials comprise selected ceramics in both their native and amphoteric forms. Such useful ceramics are those with residual lattice charges or an unbalance of charge in the fundamental framework or layers such as vermiculite, bentonite, hectorite, zeolites, selected micas including Glauconite, phlogopite and Biotite and mixtures thereof.

Abstract: Disclosed are ceramic oxide gels (sometimes also referred to as hydrated oxides), and especially xerogels, compositions which are useful in the formulation and fabrication of microwave susceptors for disposable packages for the microwave heating of food items. The compositions include novel microwave absorbing ceramic gel material doped with common salt and a binder. The gel forming materials include alumina, silica, mullite and mixtures thereof. The compositions essentially comprise about 17% to 35% bound water. Preferred materials are xerogels, i.e., ceramic gels dried so as to have a free moisture content of about 0.1% to 10%. The compositions provide good heat generation and a predeterminable upper temperature limit. The materials are common and inexpensive. The compositions can additionally include common salt as a temperature profile moderator.

Abstract: A protective cover for a dish being heated in a microwave oven is formed of moisture-absorbent, microwave transparent material forming a top member and an encircling wall member depending downwardly from the periphery of the top member to completely cover the dish to protect the interior of the oven from any possible spattering of food particles during the heating. The cover is formed of absorbent material so that any escaping fluids and food particles may be captured or absorbed by the cover. The wall member is fluted to give the cover self-supporting rigidity, and an upper edge of each fluted portion coincides with a scalloped portion of the top member. The cover may be treated with a microwave safe resin to increase the rigidity of the cover.

Abstract: A disposable, self-supported tray, for holding food in a microwave oven, which tray includes a paperboard center panel coated on at least one side with a conductive material and supported at the periphery and in the center by downwardly extending panels, certain of which have interlocking engagement with each other.