Food product surface sterilization apparatus and method

Abstract

An apparatus is disclosed for the micro-organism surface sterilization of foods using, a "germicidal" such as light waves (e.g., ultraviolet), and in some cases in combination with (or replaced by) one or more of sound waves and ozone. The surface sterilizer apparatus may include a plurality of germicidal (e.g., ultraviolet) emitters for surface sterilization of foods that are, e.g., rotated in a drum or rotated via a screw auger. Assemblies of emitters for the germicidal may be constructed to be watertight (i.e., withstand a high pressure, heated water spray), and movable relative to the drum or screw conveyor for easy cleaning and maintenance. The apparatus may also include a controller (e.g., programmable logic controller) for controlling the sterilization process so that the apparatus does not endanger personnel nearby, and so that the food is properly sterilized. The controller may vary the amount of germicidal used, the rate that food traverses the apparatus, the inclination of the apparatus, and terminate sterilization processing when an unsafe condition is detected. The apparatus may be used in-line with other food processing equipment for the real-time sterilization of food. The controller may also communicate with food processing components upstream of the apparatus for controlling the flow of food to the surface sterilizer

Description

[0001] The present application claims the benefit of, and incorporates fully by reference, each the following: U.S. Provisional Patent Application Serial No. 60 / 393,792 filed Jul. 3, 2002; U.S. Provisional Patent Application Serial No. 60 / 393,363 filed Jul. 3, 2002; and U.S. Provisional Patent Application Serial No. 60 / 449,725 filed Feb. 24, 20034.RELATED FIELD OF THE INVENTION[0002] The present invention relates generally to the field of sterilization equipment, and, more specifically, to a device for surface sterilization of foodstuffs of various regular or irregular shapes, this device includes a combination of germicidal radiation, ozone and a device for rotating and conveying the foodstuffs such as (a) a rotating drum that lifts, tumbles, and advances the foodstuff within the drum in the presence of the germicidal radiation, and (b) a screw conveyor that lifts, tumbles, and advances the foodstuff within the screw conveyor in the presence of the germicidal radiation and / or ozone...

AI Technical Summary

Benefits of technology

[0033] It is an aspect of the surface sterilizer of the present invention that as the foodstuff transverses the transport, the foodstuff is rearranged and reoriented in the transport so that there is a substantially uniform exposure to all surfaces of the foodstuff by the germicidal. Accordingly, the surface sterilizer may include various foodstuff supports that generally rotate within the transport. These supports (denoted herein as "tumblers") at least partially support the food products so that the food products are carried a greater extent upwardly, as the foodstuff progresses through the transport, than would otherwise occur without the tumblers. In particular, it is an aspect of the invention that such tumblers may be configured so that most or substantially all of the individual food product items tumble downwardly over (or under) a boundary for the food product support surfaces of the tumblers thus substantially assuring that individual food products have all their surfaces exposed to a sterilizing concentration of the germicidal. That is, the rotationally upwardly carried food products generally tumble (e.g., over or under a tumbler edge) from their tumbler supports when the supports reach an upwardly inclined position sufficient for the food products to tumble off. Thus, such tumbling causes the food products to be rearranged and reoriented for more uniform exposure to the germicidal.

[0055] For embodiments of the invention having a rotating drum and that utilize UVC for foodstuff sterilization, the transport of the surface sterilizer (e.g., a rotating drum or an auger trough) may have inlet and discharge UVC attenuating baffles or radiation baffle structure to thereby create a substantially enclosed housing for at least one of: (a) containing substantially all of the ultraviolet radiation within the volume of the transport, and (b) altering the ultraviolet radiation that may escape from the transport so that the escaping radiation is no longer considered a threat to humans; and therefore, meeting OSHA and related safety requirements for personnel working in the vicinity of this embodiment of the invention. In some preferred embodiments, the baffles or baffle structure is made of translucent materials that allow visibility of the food product inside the transport. Moreover, when the surface sterilizer includes an auger trough, the lid (that encloses the UVC light assemblies above or adjacent to the trough) is constructed of a UVC attenuating material, to create a substantially enclosed volume for human harmful radiation.

Problems solved by technology

However, the chemicals used are costly and may leave a residue, which can be ingested by the consumer.

Moreover, such chemical treatments are not always effective in view of the numerous instances of live and dead insects and mold still encountered in packaged dry foodstuff products.

In the freezing and packaging processes, the probability of surface re-contamination of the foodstuff exists.

This apparatus is limited to products, which have a shape that is round or spherical, and smooth.

This apparatus has the disadvantage of the potential of shadowing, which reduces the probability that all surface areas are exposed to the UVC germicidal light source.

This apparatus has the disadvantage of not continuously tumbling and turning the product to be sterilized, thus reducing the probability of exposing all surfaces to the ultraviolet light energy.

Such radiation penetrates packaging film relatively easily but may not be very effective at impairing or killing microorganisms.

Moreover, such irradiation may have deleterious effects on meat quality, e.g. associated with photochemical oxidation of lipids and / or pigments.

That is, Tanka's technique of treating a product with a surface sterilizing agent after packaging is only effective on those surfaces that are exposed through the packaging material.

Note, however, that the action of such guides pushing the product against the friction on the conveyor belt may cause damage to fragile products.

However, it is unclear how such material would maintain such a UV transmissive quality in a commercial food product setting without becoming substantially opaque due to residue build up and / or abrasion or scratching.

Moreover, even if an appropriate UV transmissive conveyor could be provided, products near the center of the conveyor may not have their surfaces adequately exposed to the UV radiation due to the shadowing of adjacent product items.

Moreover, the positioning of the UV lights appears problematic (e.g., at least those below Newman's drum, and possibly also those above the drum, depending on the drum rotational speed) for product items that cast off dirt, debris or any liquid (e.g., water) in that the UV lights will become progressively less light transmissive unless the sterilization process is repeatedly stopped so that lights can be cleaned.

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