Process for sanitizing contaminated animal carcasses and tissues

Abstract

A method (200) for sanitizing a load of contaminated animal carcasses and biologic tissues within an autoclave chamber without requiring an autoclave bag, wherein the contaminated load is contained within a sealable decontamination vessel assembly (100, 300) incorporating selectively sealable vent structures (120, 370) that automatically bias from a closed, sealed state to an open, unsealed state upon exposure to predetermined temperature and pressure conditions within the autoclave chamber. The load-containing decontamination vessel assembly (100, 300) is exposed to a series of vacuum-pressure (Pre-Vac) cycles within the autoclave chamber to effect separation of solids and liquids within the biologic tissues, and subsequently heated to an internal load sterilization temperature (e.g., 121 °C) for a period of time (e.g., 30-40 minutes) adequate to effect complete sterilization of the contaminated load.

Description

PROCESS FOR SANITIZING CONTAMINATEDANIMAL CARCASSES AND TISSUESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This PCT patent application claims priority to co-pending U.S. provisional patent application number 63 / 528,988, filed on July 26, 2023, the entire contents of which are incorporated by reference herein.FIELD OF THE INVENTION

[0002] The present invention relates to the sterilization of contaminated animal carcasses and tissues. More particularly, the present invention concerns an improved sterilization method for decontamination of animal carcasses and tissue that is more effective and efficient than conventional sterilization processes.BACKGROUND OF THE INVENTION

[0003] Autoclave sterilization is commonly used to decontaminate animal carcasses and biologic tissues. For example, autoclave sterilization is conventionally used to sterilize contaminated murine carcasses (i.e., carcasses of mice, rats, and some related rodents).

[0004] Current processes require a contaminated murine carcass to be temporarily placed into a sealable plastic bag and stored in a refrigerator / freezer until the carcass can be sterilized. During standard decontamination procedures, when carcasses are processed for removal from a containment laboratory, the sealed plastic bags are placed into an autoclave bag within a Biological Safety Cabinet (BSC), the autoclave bag is sealed using autoclave tape, placed into a stainless-steel autoclave pan (and covered with a stainless steel lid or aluminum foil), the autoclave pan surfaces are decontaminated, and then the autoclave pan holding the autoclave bag is transferred to the autoclave chamber. Thermal inactivation of the majority of infectious agents is achieved using moist heat sterilization at 121 °C (250°F) for a period of time needed to completely sterilize the contaminants.

[0005] Since the autoclave bag remains sealed there is a lack of exchange of steam / heat to the carcass and corresponding animal tissue (i.e., the load). Consequently, additional time is required to heat the air trapped within the autoclave bag to the sterilization temperature. During the heating and sterilization phases the internal load temperatures fluctuate by as much as 20°C. When there is a drop in internal load temperature (i.e., from the 121 °C sterilization temperature) an additional 15 minutes ormore may be required to recover to the required sterilization temperature. Accordingly, the non-uniform heating / temperature throughout the load further contributes to the total sterilization process time.

[0006] Processing times required to achieve sterilization commonly range from 3 to 7 hours, and sometimes longer. There has been a continuous effort in the animal waste decontamination industry to find ways to reduce decontamination times while still achieving complete sterilization. However, for the most part, such efforts have been to no avail.

[0007] Accordingly, there has been a long-felt, unmet need in the animal waste decontamination industry, e.g., in Biosafety Level (BSL) labs, for an improved autoclave sterilization process that can consistently decontaminate animal carcasses (and associated animal tissues) more effectively and more efficiently (i.e., faster) than conventional methods.SUMMARY OF THE INVENTION

[0008] The present invention provides a sealable decontamination vessel assembly and a corresponding method of using the sealable decontamination vessel assembly to decontaminate, or sterilize, a load of animal carcasses and / or biologic tissues within a conventional autoclave chamber.

[0009] In accordance with a first general aspect of the invention, the sealable decontamination vessel assembly may include: an outer vessel having a bottom side and a continuous sidewall extending upwardly from a periphery thereof and terminating at an upper end, together defining an interior holding chamber of the outer vessel, wherein a first load temperature probe receiving opening is defined through the continuous sidewall, and a vent hole is defined through the continuous sidewall; an inner receptacle having a bottom side and a perforated continuous sidewall extending upwardly from a periphery thereof, together defining an interior confinement chamber of the inner receptacle, wherein a second load probe receiving opening defined through the perforated continuous sidewallis linearly aligned with the first load probe receiving opening of the outer vessel when the sealable decontamination vessel assembly is fully assembled; a selectively sealable vent structure integrated with the continuous sidewall of the outer vessel for controlling fluid communication through vent hole in the outer vessel sidewall; and an outer vessel lid sealingly attachable to an open top of the outer vessel.

[0010] In some implementations, the selectively sealable vent structure may include a sealing member disposed exteriorly of the continuous sidewall of the outer vessel, which prevents fluid communication through the vent hole in the continuous sidewall prior to using the sealabledecontamination vessel assembly to sterilize a load of contaminated animal carcasses and biologic tissue.

[0011] In some implementations, a vent plate may be disposed upon the exterior surface of the continuous sidewall of the outer vessel, wherein the vent plate has a vent plate opening coextensive with the outer vessel vent hole.

[0012] In some implementations, the sealing member may comprise a biodegradable seal disposed upon the vent plate and sealingly covering the vent plate opening and coextensive outer vessel vent hole.

[0013] In some implementations, the selectively sealable vent structure may employ a bellows thermostat integrated with the continuous sidewall in lieu of biodegradable patches.

[0014] In some implementations, one or more wall spacers may be provided upon an interior surface of the outer vessel continuous sidewall to maintain a gap between the outer vessel continuous sidewall and the perforated sidewall of the inner receptacle.

[0015] In some implementations, the sealable decontamination vessel assembly may include a load containment bag containing a load of contaminated biologic tissue, wherein the load containment bag is received and supported within the interior confinement chamber of the inner receptacle.

[0016] In some implementations, the outer vessel lid may include a lid vent hole and a corresponding selectively sealable vent structure integrated into a central panel of the outer vessel lid for controlling fluid communication through the lid vent hole.

[0017] In accordance with a second general aspect of the invention, a method is provided for sterilizing a load of contaminated animal carcasses and / or biologic tissue within an autoclave chamber using the sealable decontamination vessel assembly of the present invention.

[0018] In some implementations, the method may include steps of: providing a sealable decontamination vessel assembly (100, 300) comprising: an outer vessel (102, 302) having a bottom side (112, 312) and a continuous sidewall (110, 310) extending upwardly from a periphery of the outer vessel bottom side, the continuous sidewall terminating at an upper end (110c, 310c), the bottom side and continuous sidewall, together, defining an interior holding chamber (116, 316) of the outer vessel, the continuous sidewall having a first load temperature probe receiving opening (118, 318) and at least one vent hole (121 , 321 ) extending completely therethrough; an inner receptacle (104, 304) having a bottom side (124, 324) and a perforated continuous sidewall (122, 322) extending upwardly from a periphery of the inner receptaclebottom side, the inner receptacle bottom side and the perforated continuous sidewall, together, defining an interior confinement chamber (130, 330), wherein the inner receptacle is received and supported within the interior holding chamber (116, 316) of the outer vessel (102, 302) such that a gap is maintained between the perforated continuous sidewall and an interior surface (110b, 310b) of the outer vessel continuous sidewall (110, 310), the perforated continuous sidewall having a second load temperature probe receiving opening (134, 334) extending completely therethrough, wherein the second load probe receiving opening is aligned with the first load probe receiving opening (118, 318) of the outer vessel (102, 302) when the sealable decontamination vessel assembly is in a fully assembled state; a selectively sealable vent structure (120, 320) integrated with the continuous sidewall (110, 310) of the outer vessel (102, 302) for controlling fluid communication through said at least one vent hole (121 , 321), wherein said selectively sealable vent structure (120, 320) is automatically biased from a closed, sealed state to an open, unsealed state when exposed to predetermined ambient temperature and pressure conditions; and an outer vessel lid (108, 308) sealingly engageable with the upper end (110c, 310c) of the continuous sidewall (110, 310) of the outer vessel (102, 302); depositing the load of contaminated animal carcasses and biologic tissue into the interior confinement chamber (130, 330) of the inner receptacle (104, 304) of the selectively sealable decontamination vessel assembly (100, 300) and sealingly attaching the outer vessel lid (108, 308) to the upper end (110c, 310c) of the continuous sidewall (110, 310) of the outer vessel, wherein the selectively sealable vent structure (120, 370) is in a closed, sealed state; introducing the sealed decontamination vessel assembly (100, 300) into the autoclave chamber and sealing the autoclave chamber from the surrounding ambient environment while the autoclave chamber is under ambient pressure and temperature conditions; subjecting the sealed decontamination vessel assembly (100, 300) to at least one autoclave vacuum-pressure cycle, wherein the vacuum-pressure cycle conditions within the autoclave chamber automatically bias the selectively sealable vent structure (120) into an open, unsealed state to thereby enable fluid communication, through said at least one vent hole (121 , 321 ), between the autoclave chamber and the interior holding chamber (116, 316) of the outer vessel (102, 302), wherein the vacuum-pressure cycle conditions in the autoclave chamber cause the separation of solids and liquids of the load of contaminated animal tissue; and heating the autoclave chamber until achieving a biologic tissue sterilization temperature (Ts) within said load of contaminated biologic tissue, and maintaining said biologic tissuesterilization temperature (Ts) within said load for a period of time adequate to achieve complete sterilization of the contaminated biologic tissue load.

[0019] In some implementations, after depositing the contaminated load into the interior confinement chamber of the inner receptacle, a temperature-sensing distal portion of a temperature reference probe may be passed through the first load temperature probe receiving opening of the outer vessel, through the second load temperature probe receiving opening of the inner receptacle, and subsequently inserted into the contaminated load. In this manner, the temperature reference probe may provide a real time indication of the internal load temperature.

[0020] In some implementations, the pre-defined biologic tissue sterilization temperature (Ts) is at least 121 °C (250°F).

[0021] In some implementations, the sterilization temperature may be maintained for a period of time within a range of 30-40 minutes.

[0022] In some implementations, the sealed decontamination vessel assembly (and thus the contaminated load) may be subjected to a series of vacuum-pressure cycles alternating between a vacuum of about 24 inches Hg and a pressure of about 13 psi for a total period of time within a range of 5-10 minutes.

[0023] In some implementations, following the heating step, a step of drying the contaminated load under vacuum in the autoclave chamber may be employed.

[0024] In some implementations, following the drying step, the autoclave chamber be exhausted until it returns to its original ambient pressure and temperature conditions.

[0025] These and other features, aspects, and advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings.BRIEF DESCRIPTION OF DRAWINGS

[0026] The invention will now be described, by way of example, with reference to the accompanying figures, where like numerals denote like elements, and in which:

[0027] FIG. 1 is an upper isometric view of a sealable decontamination vessel assembly for use with the process / method of the present invention;

[0028] FIG. 2 is an upper isometric view of the sealable decontamination vessel assembly originally introduced in FIG. 1 , with the vessel lid removed to expose a load containment bag nested within a perforated inner receptacle seated within an outer vessel of the assembly;

[0029] FIG. 3 is an upper partially-exploded isometric view of the sealable decontamination vessel assembly originally introduced in FIG. 1 , showing both the vessel lid and the load containment bag removed to further expose the interior of the perforated inner receptacle still seated within the outer vessel of the assembly;

[0030] FIG. 4 is an upper fully-exploded isometric view of the sealable decontamination vessel assembly originally introduced in FIG. 1 , showing the outer vessel lid, the load containment bag, and the perforated inner receptacle removed from an interior holding chamber of outer vessel;

[0031] FIG. 5 is a top plan view of the fully-assembled sealable decontamination vessel assembly originally introduced in FIG. 1 ;

[0032] FIG. 6 is an upper isometric view of the outer vessel lid originally introduced in FIG. 1 ;

[0033] FIG. 7 is a longitudinal cross-sectional view of the fully-assembled sealable decontamination vessel assembly taken along sectional line 7-7 of FIG. 5;

[0034] FIG. 8 is a flow chart of an exemplary implementation of the animal carcass and tissue sanitization process of the present invention;

[0035] FIG. 9 is an upper isometric view of a sealable decontamination vessel assembly in accordance with an alternative embodiment of the present invention;

[0036] FIG. 10 is a longitudinal cross-sectional view of the fully-assembled sealable decontamination vessel assembly of the fully-assembled sealable decontamination vessel assembly (similar to FIG. 7) of the alternative embodiment presented in FIG. 9 illustrating a bellows-type thermostat in a closed, sealed state; and

[0037] FIG. 11 is a longitudinal cross-sectional view of the fully-assembled sealable decontamination vessel assembly of the fully-assembled sealable decontamination vessel assembly (similar to FIG. 7) of the alternative embodiment presented in FIG. 9 illustrating a bellows-type thermostat in an open, non-sealed state.

[0038] Like reference characters / numerals refer to like parts throughout the several views of the drawings.DESCRIPTION OF THE INVENTION

[0039] The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construedas preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. There is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that any specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Other embodiments may be utilized, and other changes made, without departing from the spirit or scope of the subject matter presented herein.

[0040] For purposes of description herein, the terms “upper,” “lower,” “left,” “right,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof, shall relate to the invention as oriented in FIG. 1.

[0041] The present invention is directed to sealable decontamination vessel assembly and method of use for decontaminating, or sterilizing, a load of contaminated animal carcasses and / or tissues - particularly, in a laboratory environment. The inventive method provides a means for effectively decontaminating such loads in a fraction of the time required using conventional sterilization procedures. The process requires the use of a specialized sealable decontamination vessel incorporating selectively sealable vents which, when unsealed, enable fluid communication between an interior of the decontamination vessel and an autoclave chamber. An exemplary sealable decontamination vessel assembly for use with the process of the present invention is disclosed in U.S. Patent No. 10,071 ,178 (the ‘178 patent), issued to the present inventor / applicant. The entire content of the ‘178 patent is incorporated by reference herein.

[0042] As disclosed in the ‘178 patent, the decontamination vessel assembly was particularly designed to overcome issues that bio-research institutes were having safely transporting airborne pathogens from under hoods (e.g., within a Biological Safety Cabinet (BSC)) into an autoclave chamber without exposing lab workers and other individuals to aerosols from open containers. In particular, hospitals dealing with people in isolation were having problems with limiting exposure to, and safe sterilization of, their contaminated clothing, needles, trash, instruments and related items. Conventionally, such contaminated items were sealed in an autoclave bag (under the hood) and then transported to the autoclave. However, once at the autoclave the bags holding the contaminated items had to be opened in order to transfer the contaminated items to the autoclave. Accordingly, the conventional process exposed individuals handling the bags and other nearby individuals to theaerosols. Applicant’s sealable decontamination vessel assembly solved this problem by providing a means for transporting decontaminated items in a sealed container from a hood to an autoclave, and subsequently inserting the sealed decontamination vessel directly into the autoclave chamber for processing without requiring unsealing of the container.

[0043] More recently, the present inventor / applicant discovered a completely new use, or application, of the decontamination vessel assembly disclosed in the ‘178 patent for vastly improving the effectiveness and efficiency of the existing processes used during the sterilization of contaminated animal carcasses and tissues.

[0044] The general structure of the exemplary sealable decontamination vessel assembly 100, for use with the inventive sanitization / decontamination process, will now be described with general reference to the drawings.

[0045] Referring generally to FIGS. 1-7, an exemplary sealable decontamination vessel assembly 100 generally includes an outer vessel 102, an inner receptacle 104, and an outer vessel lid 108. Optionally, the decontamination vessel assembly 100 may further include a load containment bag 106

[0046] Outer vessel 102 includes a bottom side 112 having a continuous sidewall 110 extending upwardly from a periphery of the outer vessel bottom side.The continuous sidewall has an exterior surface 110a, an opposite interior surface 110b and an outwardly-flared upper end 110c, and a bottom end wall 112. Together, continuous sidewall 110 and bottom end wall 112 define an interior holding chamber 116. Vent holes 120 may be provided extending completely through continuous sidewall 110, enabling fluid communication therethrough when the vent holes are not sealed. Outer container sidewall plates 154 having sidewall plate apertures 154a may be disposed upon the exterior surface 110b of outer container sidewall 110, such that the sidewall plate apertures are aligned with the outer container vent holes 120. As discussed further herein, biodegradable seal patches 160 may be disposed upon the outer container sidewall plates 154 during use. A plurality of spaced-apart clasp devices 162, each including a latch hook 166, may be integrated into outer container sidewall 110 proximate to outwardly-flanged upper end 110c. During use, the clasp devices 162 are used to secure, and seal, outer container lid 108 to outer container 102. In a closed state, free ends 166a of latch hooks 166 frictionally engage spaced-apart latch engagement depressions 168 in an upper periphery of outer container lid 108. A load probe opening 118 is provided extending completely through sidewall 110 of outer container 102. A plurality of spaced-apart vertically-extending wall spacers 114 may be provided projecting interiorly from interior surface 110b of outer container sidewall 110 to interior edges 114a of the wall spacers.

[0047] Perforated inner receptacle 104 is at least partially defined by a continuous sidewall 122 and a bottom end wall 124, together, defining an interior load containment bag confinement chamber 130. At its upper end, sidewall 122 terminates at an upper lip 128. As its name implies, perforated inner receptacle 104 has a plurality of perforations 126 extending completely through sidewall 122; from an exterior sidewall surface 122a to an interior sidewall surface 122b. A load probe opening 134 is provided extending completely sidewall 122 as well. During assembly, when perforated inner receptacle 104 is properly seated within outer container 102 -- such that standoffs 136, or feet, projecting downwardly from exterior surface 124a of bottom end wall 124 of perforated inner receptacle 104, are seated within standoff-receiving depressions 138 in the interior surface 112b of the outer container bottom end wall 112 -- inner receptacle load probe opening 134 aligns with outer container load probe opening 118 to facilitate passage of a load temperature probe (not shown) therethrough.

[0048] Load containment bag 106 is constructed of a flexible material, such as a suitable plastic material capable of withstanding the high pressures and temperatures typically encountered within an autoclave chamber. Load containment bag 106 has an outwardly-flanged upper end 140 and a loadholding interior space 142. The load-holding interior space 142 is accessible through the outwardly- flanged open upper end 140 of load containment bag 106 to enable contaminated animal carcasses / tissues to be deposited therein. Preferably, the load containment bag 106 is sized, shaped and otherwise configured, to be easily inserted through the open upper end 140 of perforated inner receptacle 104 and lie along the interior surfaces, 122b and 124b, respectively, of the perforated side wall 122 and bottom end 124 of the inner receptacle. In this manner, the load containment bag 106 is generally nested within the perforated inner receptacle 104, with the outwardly-flanged upper end 140 of the load containment bag supported upon and draped over the upper lip 128 of the perforated inner receptacle.

[0049] Outer container lid 108 is at least partially defined by a central panel 144 terminating peripherally at an annular outer skirt 146. A lid handle 152 is attached to the exterior surface central panel 144 for manually attaching the outer container lid 108 to, or removing the outer container lid from, outer container 102. As previously described, a plurality of spaced-apart latch engagement depressions may be provided in an upper surface of annular outer skirt 146 of outer container lid 108, for selective engagement with corresponding free ends 166a of latch hooks 166 of clasp devices 162. Outer container lid vent holes 150 may be provided extending completely through central panel 144 of outer container lid 108, enabling fluid communication therethrough when the outer container lid vent holes are not sealed. Outer container lid plates 156 having lid plate apertures 156a may be disposed upon the exterior surface of central panel 142, such that the lid plate apertures are aligned with the outercontainer lid vent holes 150. As discussed further herein, biodegradable seal patches 160 may be disposed upon the outer container lid plates 156 during use. Alternatively, lid plates 156 and / or biodegradable seal patches 160 may be disposed directly upon the exterior and interior surfaces, 110a and 110b, respectively, of the outer container sidewall 110. As shown in FIG. 7, an annular sealing gasket 164 may be provided upon outwardly-flanged upper end 110c of outer container sidewall 110 to maintain a seal between outer container 102 and outer container lid 108 when clasp devices 162 (and outer container lid 108) are in a closed state.

[0050] Referring particularly to FIG. 7, sealable decontamination vessel assembly 100 is shown in a fully assembled condition (i.e., ready for use in connection with the sterilization process of the present invention).

[0051] With regard to the original decontamination process (i.e., used for sterilization of items other than animal carcasses and tissues), special biodegradable seals 160 were applied before each use. The seals were designed to biodegrade, or deteriorate, under predefined heat and pressure conditions during the autoclave cycle to enable fluid communication through the respective vent holes 120, 150. Through experimentation, applicant has found that the original vent structure employing biodegradable seals is adequate to carry out the method of the present invention. However, in an alternate embodiment of the invention, a bellows thermostat may be employed in lieu of biodegradable seals.

[0052] Referring now particularly to FIGS. 9-11 , an alternate embodiment of the invention is presented using a sealable decontamination vessel assembly 300 employing a bellows thermostat in lieu of the biodegradable seals. Sealable decontamination vessel assembly 300 employs a virtually identical structure to the sealable decontamination vessel assembly 100 described above, except for the incorporation of a bellows type thermostat. For simplicity, applicant has used identical reference characters for components that are common to both embodiments; except that the reference numerals in the alternate embodiment are preceded by a “3” instead of a “1”.

[0053] Sealable decontamination vessel assembly 300 is provided having a selectively sealable vent structure 320 integrated with the continuous sidewall 310 for controlling fluid communication through at least one vent hole 321 , wherein the selectively sealable vent structure incorporates a bellows thermostat 370 in lieu of (i.e., instead of) the biodegradable seal patch 160 and vent plate 154. Applicant has found that the bellows thermostat provides significant advantages and benefits vis-a-vis the biodegradable seal patch 160 and vent plate 154 structure. One advantage of the bellows thermostat is that it is re-usable; that is, it does not require the application of new seal patches betweenuses. Another advantage of the bellows thermostat is that it is much more reliable / controllable than the seal patches.

[0054] The function of the bellows thermostat will be well understood by those skilled in the art. In this exemplary implementation, the bellows thermostat 370 is integrated into the interior surface 310a of the continuous sidewall 310 in the gap (Gi) defined between the interior surface 310a of continuous sidewall 310 and the exterior surface 322a of continuous sidewall 322 of the perforated inner receptacle 304. Many forms of a conventional bellows thermostat, such as those used in vehicles, may be employed. As shown, the operational components of the bellows thermostat 370 may be contained within an interior space 376 of the bellows thermostat housing 372. Bellows thermostat housing 372 may include a front wall / face 374. A central opening 375 in the front wall 374 may define an interior flange surface 374a against which the bellows thermostat plate 390 is sealingly engaged when the bellows thermostat is retracted in a closed, sealed condition or state (See FIG. 10).

[0055] Again, the bellows thermostat 370 may include a sealing plate 390 that remains in a retracted state to seal an interior holding chamber 316 of the outer container 302 prior to insertion into the autoclave chamber. However, when a predefined temperature (e.g., 71 °C / 160°F) is achieved within the autoclave chamber the bellows, which may take the form of a compression spring 388, will automatically expand; causing the sealing plate 390 to translate, or extend, away from interior flange surface 374a toward the outer container sidewall 310 and, thereby, unseal the vent to provide fluid communication through the outer container sidewall 310. During cooling of the autoclave chamber, when the internal autoclave temperature drops below the predefined temperature the bellows (and corresponding sealing plate) will retract, or translate, toward the corresponding outer container sidewall 310 to reseal the interior holding chamber 316.

[0056] Regardless of the venting structure employed, what is crucial is that the outer container 102 (and / or outer container lid 108) incorporates a sealable vent structure that automatically deploys into an open, non-sealed state within the closed / sealed autoclave chamber when predefined temperature / pressure conditions are achieved.

[0057] Following more recent experimentation, the present inventor discovered at least two reasons for the excessive amount of time required during conventional animal carcass and tissue sterilization processes (i.e., reasons why conventional animal carcass / tissue sterilization procedures require so much time to achieve complete sterilization of the animal carcass / tissue load). One reason is that air in the sealed autoclave bag containing the load acts to impede the transfer of steam / heat to the load, thereby requiring additional time to heat the air trapped within the autoclave bag to the requiredsterilization temperature. Another reason is that during the sterilization phase of the conventional decontamination process, pockets of liquid within the animal tissues act to insulate the tissues from the hot pressurized steam in the autoclave chamber. As a result, internal load temperatures are not uniform, and they fluctuate during heating and sterilization phases. Consequently, additional processing time is typically required to raise the temperatures of internal portions of the load where the temperature has dropped below the required sterilization temperature.

[0058] In the course of the present inventor’s research and experimentation, it was discovered that incorporating pre-vacuum cycles during the load sterilization process, in conjunction with the use of a decontamination vessel assembly incorporating automatically sealing vents (i.e., vents that remain sealed under ambient conditions, but automatically unseal when predefined above-ambient temperature and pressure conditions are achieved), it was possible to force liquid out of the animal tissues during the sterilization process. Surprisingly, this resulted in significantly faster and more uniform heating and sterilization of the load.

[0059] Referring now particularly to FIG. 8, in accordance with an exemplary implementation, the improved animal carcass / tissue sterilization process 200 may include the following steps:

[0060] Initially, at step 202, a contaminated load (e.g., animal carcass and tissue) is provided contained within a sealed plastic bag. The load-holding plastic bag may be constructed from a polymer that melts - or otherwise degrades - during exposure to sterilization process conditions within the autoclave chamber. By way of example, the load-holding plastic bag may be comprised of a mix of low- density and linear-low-density polyethylene (LDPE) such as ZIPLOC brand plastic bags.

[0061] In step 204, a decontamination vessel 100, 300 is provided incorporating selectively sealing vent structures 120, 370 and assembled into a closed, sealed configuration. That is, a configuration wherein the outer vessel 102, 302 of the vessel assembly 100, 300 is sealed with an outer container lid 108, 308 and any vent structures 120, 370 are in a sealed state.

[0062] Subsequently, in step 206, the outer vessel lid 108, 308 is temporarily removed, the loadholding plastic bag is deposited into an interior holding chamber 116, 316 of the outer vessel 102, 302, and then the outer vessel is resealed with the vessel lid. With regard to the exemplary sealable decontamination vessel assemblies 100, 300 the load-holding plastic bag may be deposited into the load holding interior space 142, 342of the load containment bag 106, 306 lining the interior surface 122b, 322b of the perforated inner receptacle 104, 304 and the perforated inner receptacle 104, 304 seated within the interior holding chamber 116, 316 of the outer vessel 102, 302.

[0063] In step 208, the sealed and assembled decontamination vessel 100 may be placed into an autoclave pan. Significantly, the inventive procedure does not require the use of an autoclave bag to contain the load. Although plastic load bags are designed to deteriorate and melt away during the sterilization process, conventional autoclave bags are constructed from heavy-duty polyethylene or from heavy-duty polypropylene for tear- and puncture-resistance, which is unaffected by autoclave chamber temperature / pressure conditions.

[0064] Optionally, the outer surfaces of the assembled decontamination vessel 100, 300 and the autoclave pan may be sterilized in the usual manner. Preferably, steps 206 and 208 are performed within a Biological Safety Cabinet (BSC) or the like.

[0065] In step 210, the sealed, assembled decontamination vessel 100, 300 (and, optionally, autoclave pan) may be transferred into an autoclave chamber under atmospheric temperature and pressure conditions, and the autoclave door sealingly closed. Optionally, a preliminary purge step may be employed to purge ambient air out of the autoclave chamber. For example, this may be accomplished by pre-heating the autoclave chamber to about 95°C for 1-3 minutes.

[0066] Subsequently, in step 212, the sealed, assembled decontamination vessel 100 may be subjected to a series of autoclave chamber vacuum-pressure (i.e., pre-vacuum) cycles adequate to bias the sealed vent structures 120, 370 into an open, unsealed state. For example, the present inventor has found success incorporating four (4) cycles alternating between vacuum (e.g., 24 inches Hg) and pressure pulses (e.g., 13psi) for a total time of about 6-7 minutes. The pre-vacuum cycles function to force liquids out of the animal tissue, thereby separating the solids from the liquids inside of the unsealed, assembled decontamination vessel 100, 300.

[0067] In step 214, following the pre-vacuum cycles, the autoclave chamber may be heated until the load sterilization temperature (Ts) is reached, and subsequently maintained at that temperature for a relatively short period of time (e.g., applicant has found success maintaining the load sterilization temperature for a time period of 3-5 minutes) until the load exhibits a uniform sterilization temperature throughout. It was discovered that following the pre-vacuum cycles, the loads exhibited uniform heating (i.e., the temperatures were consistent throughout the load during the entire sterilization phase) and the loads reached a desired sterilization temperature (i.e., 121 °C) significantly faster than conventional animal loads sterilized in a sealed autoclave bag.

[0068] Subsequently, in step 216, the load sterilization temperature is maintained for a period of time (e.g., applicant has found success maintaining the load sterilization temperature for a time period of 30-40 minutes) required to reach complete (i.e., 100%) load sterilization. Finally, in step 218, the loadmay be dried under vacuum for a short period of time (e.g., 5 minutes), and then removed from the autoclave chamber once the chamber has returned to ambient conditions.

[0069] Optionally, the process may incorporate a step of passing a temperature probe through aligned load probe openings, 118 and 134, in the respective outer vessel and inner receptacle sidewalls, 110 and 122, and subsequently inserting a temperature sensing distal end of the temperature probe into the animal carcass and tissue load being sanitized in order to monitor the internal load temperature during some or all of the process.

[0070] Extensive experimental data has shown that, in accordance with the process of the present invention, animal tissue and carcass loads are able to be completely and consistently sanitized, or decontaminated, within approximately one hour (1 hr.). This is a remarkable and unexpected improvement over conventional animal tissue / carcass sanitization methods, which typically require at least 3 to 7 hours (3-7 hrs.) to complete.

[0071] The above-described embodiments are merely exemplary illustrations of one or more implementations set forth for a clear understanding of the principles of the invention. Many variations, combinations, modifications or equivalents may be substituted for elements thereof without departing from the scope of the invention. Therefore, it is not intended that the invention be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all the embodiments falling within the scope of the appended claims.

Claims

CLAIMSWhat is claimed is:1 . A method for sterilizing a load of contaminated animal carcasses and biologic tissue within an autoclave chamber, comprising steps of: providing a sealable decontamination vessel assembly (100, 300) comprising: an outer vessel (102, 302) having a bottom side (112, 312) and a continuous sidewall (110, 310) extending upwardly from a periphery of the outer vessel bottom side, the continuous sidewall terminating at an upper end (110c, 310c), the bottom side and continuous sidewall, together, defining an interior holding chamber (116, 316) of the outer vessel, the continuous sidewall having a first load temperature probe receiving opening (118, 318) and at least one vent hole (121 , 321 ) extending completely therethrough; an inner receptacle (104, 304) having a bottom side (124, 324) and a perforated continuous sidewall (122, 322) extending upwardly from a periphery of the inner receptacle bottom side, the inner receptacle bottom side and the perforated continuous sidewall, together, defining an interior confinement chamber (130, 330), wherein the inner receptacle is received and supported within the interior holding chamber (116, 316) of the outer vessel (102, 302) such that a gap is maintained between the perforated continuous sidewall and an interior surface (110b, 310b) of the outer vessel continuous sidewall (110, 310), the perforated continuous sidewall having a second load temperature probe receiving opening (134, 334) extending completely therethrough, wherein the second load probe receiving opening is aligned with the first load probe receiving opening (118, 318) of the outer vessel (102, 302) when the sealable decontamination vessel assembly is in a fully assembled state; a selectively sealable vent structure (120, 320) integrated with the continuous sidewall (110, 310) of the outer vessel (102, 302) for controlling fluid communication through said at least one vent hole (121 , 321), wherein said selectively sealable vent structure (120, 320) is automatically biased from a closed, sealed state to an open, unsealed state when exposed to predetermined ambient temperature and pressure conditions; and an outer vessel lid (108, 308) seal i n gly engageable with the upper end (110c, 310c) of the continuous sidewall (110, 310) of the outer vessel (102, 302);depositing the load of contaminated animal carcasses and biologic tissue into the interior confinement chamber (130, 330) of the inner receptacle(104, 304) of the selectively sealable decontamination vessel assembly (100, 300) and sealingly attaching the outer vessel lid (108, 308) to the upper end (110c, 310c) of the continuous sidewall (110, 310) of the outer vessel, wherein the selectively sealable vent structure (120, 370) is in a closed, sealed state; introducing the sealed decontamination vessel assembly (100, 300) into the autoclave chamber and sealing the autoclave chamber from the surrounding ambient environment while the autoclave chamber is under ambient pressure and temperature conditions; subjecting the sealed decontamination vessel assembly (100, 300) to at least one autoclave vacuum-pressure cycle, wherein the vacuum-pressure cycle conditions within the autoclave chamber automatically bias theselectively sealable vent structure (120) into an open, unsealed state to thereby enable fluid communication, through said at least one vent hole (121 , 321), between the autoclave chamber and the interior holding chamber (116, 316) of the outer vessel (102, 302), wherein the vacuum-pressure cycle conditions in the autoclave chamber cause the separation of solids and liquids of the load of contaminated animal tissue; and heating the autoclave chamber until achieving a biologic tissue sterilization temperature (Ts) within said load of contaminated biologic tissue, and maintaining said biologic tissue sterilization temperature (Ts) within said load for a period of time adequate to achieve complete sterilization of the contaminated biologic tissue load.

2. The method recited in claim 1 , further comprising, after the step (206) of depositing the load of contaminated biologic tissue into the interior confinement chamber (130, 330) of the inner receptacle (104, 304), a step of successively passing a temperature-sensing distal portion of a temperature reference probe through the first load temperature probe receiving opening (118, 318) of the outer vessel (102, 302) and the second load temperature probe receiving opening (134, 334) of the inner receptacle (104, 304), and subsequently inserting the temperaturesensing distal portion of the temperature reference probe into the contaminated biologic tissue load, wherein the temperature reference probe provides a real time indication of the internal load temperature.

3. Themethod recited in claim 2, further comprising a step (216) of maintaining the biologic tissue sterilization temperature (Ts) within said load of contaminated biologic tissue for a period of time within a range of 30-40 minutes.

4. The method recited in claim 1 , wherein the biologic tissue sterilization temperature (Ts) is at least 121 °C (250°F).

5. The method recited in claim 1 , further comprising a step (216) of maintaining the biologic tissue sterilization temperature (Ts) within said load of contaminated biologic tissuefor a period of time within a range of 30-40 minutes.

6. The method recited in claim 1 , wherein the step (212) of subjecting the sealed decontamination vessel assembly (100, 300) to at least one vacuum-pressure cycle further comprises subjecting the sealed decontamination vessel assembly to a series of vacuum-pressure cycles alternating between a vacuum of about 24 inches Hg and a pressure of about 13 psi for a total period of time within a range of 5-10 minutes.

7. The method recited in claim 1 , further comprising, after the heating step (214) and the temperature maintaining step (216), a step (218) of drying the load of contaminated biologic tissue under vacuum in the autoclave chamber.

8. The method recited in claim 1 , further comprising, after the drying step (218), a step of exhausting the autoclave chamber until it returns to ambient pressure and temperature conditions.

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