PATENTREPORT

This section provides information on worldwide patents relevant to food control. Each report gives the following information: title of patent, patentee, patent number, publi- cation date and summary of the patent. The reports have been selected from ‘Food Processing Patent Profiles’ with permission of Derwent Publications Ltd.

Refrigerator container with computer controlled liquid nitro- gen evaporation system, for e.g. food transport Welz F Int Transpor Eur 357-587; 7 March 1990 The atmosphere of a refrigerator container is recirculated for given periods by a blower, controlled by a computer. Liquid nitrogen is heated before admission in the container to a temperature slightly below that in the cold chamber. The container has a cold chamber and an equipment chamber which encloses the N, bottles, the CO1 bottles, the refriger- ator and the computer. Nitrogen is heated to nearly the temperature in the cold chamber as it passes from the pipe to the heat exchangers and through a nozzle. The container atmosphere is recycled by a blower through the evaporator of the refrigerator and through openings. The piping for the refrigerant has an evaporation pressure regulator in parallel to a bypass valve, followed by a compressor. A computer and sensor box control all valves. Useladvantage. For wheeled transport of food, flowers, meat, vegetables, fruit, chemicals, pharmaceuticals etc. This main- tains a uniform atmosphere and temperature over long periods to preserve the high quality of the stored goods.

001-90

Treating liquid egg or egg white - while flowing in tube with microwave energy to increase shelf life Worthington Foods Eur 352-437; 31 January 1990 To inactivate or destroy a sufficient amount of the micro- organisms contained in the liquid egg, it is subjected to continuous microwave energy while it is flowing through a conduit for a given time. The process does not sufficient!y reduce the egg protein functionality of the liquid material. During the treatment. the tcmperaturc of the liquid egg rises to above 162°C.

Preferably the egg is subjected to the microwave cncrgy for a time sufficient to raise its temperature to 185°C. After the heat treatment, the liquid egg is rapidly cooled to about 50°C or below and aseptically filled into sterile containers. Prcfer- ably the diameter of the conduit through which the egg flows during microwave treatment does not cxcecd the radiant penetration depth of the energy source. Use/advantage. The process is used to treat either egg white or whole egg using microwave radiation. The resulting processed egg white is virtually bacteria-free and has cx- tended shelf life under refrigeration when filled into contain- ers under aseptic conditions. 002-90

Microwave apparatus for heating produce in discrete packages - has field deflecting and concentrating guide to produce raised value of energy in field in interior region of package A PV Magnetronics L T Eur 354-277; 14 February 1990 The microwave field in a rectangular waveguide is concen- trated between opposite faces of a pair of vanes which are

shaped to shield the outer edges of the packages transported on a microwave-transparent conveyor belt. Uniform distribu- tion of energy is achieved by choice of the proportions of the tunnel between the vanes whose edges are covered by dielectric sheaths. This distances them from the belt and stops local overheating at the bases of the packages. Vanes may be positioned above the packages in addition to, or instead of, those which supply energy from beneath. Useladvantage. For e.g. pasteurisation of food products in large quantities. Produce is heated uniformly by injection of microwave energy into continuous-flow passage. 003-90

Determining ammonia levels in samples - using glutamate dehydrogenase, alpha-ketoglutarate and reduced nicotinamide hypoxanthine dinucleotide phosphate Abbott Laboratories Eur 351-774; 24 January 1990 A method for determining the amount of ammonia in a sample comprises (a) contacting the sample glutamate dehy- drogenase (GLDH), alpha-ketoglutarate (AKG) and reduced nicotinamide hypoxanthine dinucleotide phosphate (NHxDPH) for a time sufficient to consume the ammonia present and (b) measuring absorbance change, e.g. spec- trophotometrically and determining the amount of ammonia present. Also claimed is a method for determining the amount of ammonia in a sample by (a) contacting the sample with AKG and NHxDPh, (b) measuring the initial absorb- ence, (c) adding GLDH for a time sufficient for all the ammonia to be consumed and (d) measuring the final absorbence, calculating the absorbage change between the initial and final absorbence and determining from this the amount of ammonia in the sample. Also claimed is a kit for determining the level of ammonia in a sample comprising (a) 16mgml-’ AKG, 572 Uml-’ GLDH, 0.05M phosphate buffer at pH 7.8-7.4, 33% glycerol (v/v), 0.05 mgml-’ bovine gamma globulin and 0.5 mgml- NaNs, (b) 4mgml-’ NHxDPH, 50% propylene glycol, 1 mgml-’ NaNI, 1 mgl-’ boric acid, 16mgml-’ bicine buffer, at gpH of 10.2 and (c) 0.01 M Tris buffer, 5 mgml-’ polyoxyethylene lauryl ether, 0.2mgml-’ dextran sulphate with an average mol. wt. of 500,000 at a pH of 8.2, each of (a), (b) and (c) packaged in separate compartments. Use/advantage. The use of NHxDPH instead of NADPH produces an increase in reaction rate. The reagents can be readily adapted to an automatic diagnostic system, thereby ensuring the reproducibility and the accuracy of the test. The method can be used for determining ammonia levels in body luids, chemical products and foodstuffs. 004-90

Monitoring and control of discrete processor - comparing feedback signal to desired boolean mask to determine whether discrete device completed its operation successfully Babcock and Wilcox Co US 4885-677; 5 December 1989 The control unit for a discrete processing device receives a boolean control signal and outputs a control signal to the device. A feedback signal from the device is compared with a rcfcrence signal from a Boolean mask to determine whether the device has completed its operation successfully without

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Patent Report

malfunction or breakdown and a real signal is output indicating the operational state of the discrete device based on the comparison.

A number of processing devices and respective control units are connected to a multiple sequence monitor, via a monitor block to deliver output signals to a sequence generator to change the order in which the steps are executed in different recipes, and to allow a step to be manually inserted in the sequence. The sequence generator outputs the boolean control signal to control the device. Use/advantage. Particularly in sequentially controlling and continuously monitoring discrete processors in bath process requiring performance of several sequential steps. e.g. pharmaceutical, pulp and paper and food processing indus- tries. Provides a control system requiring minimal amount of microprocessor space and computing time and may be implemented in known distributed process control computers. 00590

Food industry plant surface cleaning - using proteolytic enzymes under acid conditions to remove proteins, lipid(s) and polysaccharide. Husek V Czech 8807-030; 12 January 1990 006-90

Foodstuff pasteurising or sterilising - by packaging and raising temperature with microwaves, maintaining with hot air and low power microwaves then cooling Off Met Attrezzatur Eur 347-623; 27 December 1989

Foodstuff, pasteurised or sterilised by microwaves at 2.450 MHz, is conveyed continuously through an oven pressurised to 2.5 bar max. to prevent the microwave transparent packaging bursting or becoming mis-shapen. Firstly, temper- ature is raised quickly to a prescribed treatment value by microwave, then stabilised by combination of lower power microwaves and hot air, then held steady with hot air only, and finally lowered by cooling. Use/advantage. Improves on prior sterilisation or pasteurisa- tion processes by making the process continuous and having a short duration because of use of microwave. This avoids the rupturing of packages due to internal pressure by pressurising of an oven. 007-90

Controlled microwave food warming - includes computer analysing data e.g. food amount then controlling microwave generators Berstorff Maschinen GMBH FRG 3830-867; 18 January 1990

Separate containers holding foodstuffs or other products to be heated by microwaves to a given temperature for a given period are conveyed on an endless belt below downwardly directed beams from a series of microwave generators. The entry and departure of each container into the treatment chamber is automatically detected and the data fed to a computer which only switches on the generators when necessary, and controls the duration of microwave emission in dependence on quantity of material in container, container size, required temperature and heating duration and any other relevant conditions. Advantage. Prevents overheating or underheating of pro- duce, with maximum economy of energy consumption.

008-90

Constant temperature fryer assembly for cooking food - has apertures positioned in fryer to provide predetermined tem- perature at varius positions along conveyor, maintaining cooking environment Raytheon Co US 4882-984; 28 November 1989

The fryer assembly comprises a tank containing cooking oil, the tank has a bottom and a device for draining oil from the bottom of the tank. A heat exchanger heats the oil drained from the tank to a predetermined temperature. The heated oil is directed downward from vector into the tank from above the food to the drainer. A conveyor transports food through the oil in the tank between the directer and the drainer. The food is submerged in the cooking oil when it is being transported. A thermostat control sensitive to the temperature of the cooking oil is electrically connected with a controller and the heat exchanger for energising the heat exchanger when the temperature of the cooking oil drops. Use. Cooking french fries, chicken, fish. 009-90

Fresh meat condition check instrument - with two pole and two resistance sensor needles in same plane Matthaus R FRG 3821-779; 21 December 1989

The actual properties of the meat (muscular tissue) of a carcass in an abattoir are determined by measuring the electrical conductivity between the inserted needle-shaped poles of an ac. voltage source. The needles for both poles are arranged in the same plane as are two resistance sensors between them which have the same length. The needles are coated with plastic material apart from the tips. Advantage. This permits a rapid and reliable determination of the condition of fresh meat, because a higher conductivity indicates the egress of cell fluid in the intercellular zones of the muscles and the lowering of meat quality. 010-90

Composite sheet stock for microwave heating - has layer of susceptor stock adhered to layer of heat-conducting micro- wave reflecting material of composite stock Sot Prod Nestle SA Eur 350-660; I7 January 1990

The composite sheet stock comprises a susceptor sheet having a dielectric support layer, a heater layer of microwave interactive material and a heat-conducting microwave reflect- ing layer. A receptacle with a self-supporting configuration for combined microwave baking and cooking of a food article, such as pizza, is constructed from susceptor stock and comprises an outwardly exposed, dielectric support layer, such as paper board, and an inwardly facing heater layer and includes a lower flat portion for supporting the food article during heating.

The lower portion may be a layer of composite stock as above, or it may be formed from at least two layers of susceptor stock without a heat-conducting layer. The lower portion of the food product is thus heated primarily by conduction, while the upper portion is heated by combined radiation from the susceptor sheet and absorption of micro- waves passing through the susceptor sheet. Use. Frozen pizza. 01 l-90

Immersion freezer for preventing food sticking to belt - consisting of metered junction of liquid nitrogen and endless belt with flights Messer Griesheim Gmbh Eur 33.5400; 29 February 1990

When food is frozen by liquid nitrogen in tunnels equipped with belt conveyors, some food with a moist surface such as

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