Abstract:
The disclosed invention relates to sterilization by infrared radiation to eliminate pathogenic bacteria such as  Salmonella, E. Coli  0157:H7 and  E. Coli  (EXEC) from articles such as medical, dental and veterinary instruments, as well as from tableware and eating utensils. The invention further relates to sterilization of soil, military and agriculture equipment to eliminate pathogenic bacteria such as hepatitis, AIDS, and anthrax, and prions such as mad cow disease using infrared radiation. Sterilization is performed by exposing the article to infrared radiation generated from heating elements positioned in an enclosed chamber.

Description:
This application claims benefit of provisional application Ser. No. 60/125,249 filed Mar. 19, 1999, provisional application Ser. No. 60/114,247 filed Dec. 30, 1998. 

   FIELD OF THE INVENTION 
   The invention relates to sterilization of objects such as medical, dental and veterinary objects, tableware and eating utensils by infrared radiation to eliminate pathogenic bacteria such as  Salmonella, E. Coli  0157:H7 and  E. Coli  (EXEC). The invention further relates to sterilization of soil, military and agriculture equipment to eliminate pathogenic bacteria such as hepatitis, AIDS, and anthrax, and prions such as mad cow disease. 
   BACKGROUND OF THE INVENTION 
   In treatment of patients in developing countries, concerns exist as to the spread of infection through use of non-sterile instruments. In addition to spread of infection, another concern is contagion from non-sterile instruments is Prion related diseases. Prion or prion related diseases such as Alzheimer disease in humans and mad cow disease in bovine species, although there is no conclusive proof, are suspected of transmission through non-sterile medical, dental and veterinary instruments. 
   Prions exist normally as innocuous cellular proteins. Prions, however, possess an innate capacity to convert into highly stabile conformations that form harmful particles which become causative agents of several deadly brain diseases of the dementia type in humans and animals. Converted prions are believed to interact with one another to destroy nerve cells in the brain, causing impaired muscle control and dementia-type illnesses. Examples of these types of illnesses include Kuru, Creutzfeldt-Jakob Disease, Fatal Familial Insomnia, Gertsmann-Straussler-Scheinker (GSS) disease, Alzheimer&#39;s Disease in humans, Bovine Spongiform Encephalopathy (“mad cow”) disease in cattle and Creutzfeldt-Jakob Disease. 
   A new variant of Creutzfeldt-Jakob Disease may have arisen through mad cow disease transmission. Since 1995 about 20 patients have been identified who exhibit Creutzfeldt-Jakob Disease-like symptoms. These symptoms include psychological problems as well as physical symptoms such as involuntary muscle contractions and difficulties in walking. In addition, new fears have arisen that a strain of Creutzfeldt-Jakob Disease attacks humans under the age of 40. 
   Most medical practitioners in third world countries treat non-sterile medical instruments with alcohol at room temperature or by boiling water at 100° C. This, however, does not necessarily kill all pathogens such those responsible for various strains of hepatitis. 
   Instruments also have been sterilized with autoclaves. Autoclaves, however, consume excessive energy and require use of purified water. Autoclaves, moreover, are unable to rapidly sterilize medical instruments. 
   Rapid sterilization of instruments is important so that those instruments can be used in successive out-patient surgeries in medical offices instead of hospitals. Rapid sterilization also is important in dental offices. In the United States, the Food and Drug Administration requires dentists to sterilize dental hand pieces. Autoclaves, however, can not achieve rapid sterilization. Autoclaves, moreover, due to difficulty in sterilizing the inside mechanics and tubing of hand pieces, can not guarantee sterilization. Autoclaves also corrode the hand pieces. These deficiencies not only endanger patients but also require dentists to procure and inventory excessive number of dental hand pieces. Due to deficiencies such as those discussed above, military and Red Cross field hospitals have found it necessary to use expensive disposable instruments. 
   Medical, dental and veterinarian instruments, after having been sterilized, must be maintained in a sterilized state over a substantial period of time. This has been accomplished by placing the instruments into a sterility bag prior to and during sterilization. 
   Sterility bags have been developed for use in autoclaves. These bags, however, are very costly for use in field operations and in developing countries. 
   Previous efforts to sterilize medical instruments to avoid transmission of mad cow disease from infected instruments have focused on use of elevated temperatures. Tests at the Neuropathogenesis Unit, Institute for Animal Health, Edinburgh, Scotland show only slight inactivation (reduction) of mad cow disease symptoms after treatment of instruments with dry heat or steam heat at 100° C. for 30 minutes. Tests at DLO-Institute for Animal Science and Health (ID-DLO), Lelystad, The Netherlands show only between 1.7 and 3.1 log reduction after 20 minutes pressure cooking at 133° C. 
   Autoclaves, since they typically are employed to treat instruments with steam at 121° C. for 15 minutes, may not be able to reduce scrapie and other prion agents to a level sufficient to prevent transmission through medical, dental and veterinary instruments of diseases such as Kuru, Gertsmann-Straussler-Scheinker Disease, Fatal Familial Insomnia, Creutzfeldt-Jakob Disease, Bovine Spongiform Encephalopathy, and variants thereof. 
   Bovine Spongiform Encephalopathy BSE and scrapie agents, as shown by Schreuder BE et al, at DLO-Institute for Animal Science and Health (ID-DLO), Lelystad, The Netherlands, 5-2-1998, are more resistant to lower temperatures and shorter time cycles and less resistant to higher temperatures and longer time cycles. 
   Yet another concern from contagion is infection from bacteria present in soil and water, especially in third world countries. Anaerobic bacteria such as  B. anthracis  which causes anthrax can form dormant spores (endospores) which can remain viable for long periods of time in soil. Anthrax is 99% lethal to unprotected individuals. 
   Attempts to control contagion in soil have used methyl bromide. In the United States, about 27,000 tons (60 million pounds) of methyl bromide are used annually in agriculture for soil fumigation, commodity and quarantine treatment, as well as structural fumigation. Globally, about 76,000 tons of methyl bromide are used each year. 
   Methyl bromide, however, is toxic not only to the target organisms but also to non-target organisms. Human exposure to high concentrations of methyl bromide can result in central nervous system and respiratory system failure, as well as specific and severe deleterious effects to the lungs, eyes, and skin. 
   In addition, methyl bromide is a significant ozone depleting substance. It is estimated that methyl bromide is at least 50 times more effective at destroying ozone than chlorine from CFCs on a per molecule basis. At the Ninth Meeting of the Parties to the Montreal Protocol, it was agreed that industrialized countries shall completely eliminate use of methyl bromide by the year 2005. Non-industrialized countries shall completely eliminate use of methyl bromide by the year 2015. 
   Various alternatives to methyl bromide for soil treatment have been or under consideration. Alternatives include 1,3-dichloropropene, dazomet, chloropicrin, and meta sodium, as well as selective contact insecticides and herbicides. For treatment of commodities, alternatives include phosphine and carbonyl sulfide, irradiation, controlled atmospheres utilizing nitrogen and carbon dioxide, &amp; heat/cold. These alternatives, moreover, are pest specific. 
   In view of the above concerns, it is apparent that a need exists for methods and devices for sterilization of instruments such as medical, dental and veterinarian instruments which avoid disadvantages such as those described above. A need also exists for preserving sterility of medical, dental and veterinary instruments. In addition, a need exists for sterilization of soil, military and agriculture equipment to eliminate pathogenic bacteria as those described above, as well as for sterilization commodities which avoid disadvantages such as those described above. 
   A concern also exists regarding spread of dangerous bacterium such as  Escherichia Coli  0157:H7.  Escherichia Coli  0157:H7 is a dangerous bacterium that is easily spread through consumption of undercooked ground beef and under pasteurized milk. This is particularly so with contaminated ground beef, where the grinding process can spread the virulent bacteria to many hamburger patties processed at the same time. Failure to wash hands or kitchen eating utensils after handling the contaminated meat can also spread the bacterium  Escherichia Coli  0157:H7 has long been recognized as an important cause of hemolytic uremic syndrome (HUS) and Colitis. According to the Center for Disease Control approximately 20,000 people eat food infected by  E. Coli  0157:H7 each year. Approximately 200 deaths annually are reported. 
     Salmonella enteritidis  is also a major concern.  Salmonella enteritidis  is spread through poultry, eggs, and egg products such as mayonnaise. Eating undercooked poultry, using cooking utensils and cutting boards used for the preparation of raw poultry without properly cleaning them, and eating eggs or egg products which have not been properly refrigerated are the primary causes of infection with  Salmonella enteritidis.    
   Other bacterial pathogens can cause food-borne illnesses. For example,  listeria monocytogenes  can cause septicemia, meningitis, and stillbirths. Infections and illnesses from  listeria monocytogenes  often result from unsanitary commercial processing of dairy, poultry, and meat products-including pizza toppings, and kill up to one-third of the people infected and 
     Campylobacter jejuni  is now the most common bacterial cause of diarrhea in industrialized countries and is caused by contaminated raw foods.  Campylobacter jejuni  is the most prevalent pathogen in poultry, and in more serious cases, can result in arthritis, septicemia, meningitis, inflammation of the heart and other organs, and Guillain-Barr6 syndrome (paralysis). 
   Parasitic infections from parasites such as the  Trichinella spiralis  can arise in humans who eat meat from an infected host animal. These parasitic infections can cause permanent damage to the eyes, heart, and other organs. Commercial food processing has greatly reduced the incidence of food-borne parasites; however, foods prepared under unsanitary processing conditions or at home-notably, cured or smoked meat may harbor these parasites. 
   Food borne pathogens die when exposed to heat for a specific amount of time. A ground beef patty cooked to 160° F. is safe. Cooking of the ground beef patty until it reaches an internal temperature of 160° F. throughout kills  E. Coli  0157:H7,  Salmonella  and  E. Coli.    
   With current technology in the form of broilers, charcoal grills and ovens, however, it is not possible to cook a hamburger patty to the juicy, medium rare state and yet be certain that  E. Coli  0157:H7,  E. Coli  or  Salmonella  have been killed. In order for the internal temperature of the hamburger patty to reach 160° F., it is necessary to cook the hamburger until reaches the well done state. The well done state, however, is much less juicy and flavorful, and looses its juicy taste. 
   Food born pathogens such as  Salmonella, E. Coli  0157:H7 and  E. Coli  (EXEC) can be transmitted by unsanitary tableware and eating utensils. Since these pathogens are resistant to chlorine, then the use of tap water may not be sufficient for cleaning tableware and eating utensils. 
   A need therefore exists for treating foodstuffs such as hamburger meat to sufficient temperature to kill  E. Coli  0157:H7,  E. Coli (EXEC),  Salmonella  and other food borne pathogens and yet avoid the aforedescribed disadvantages. 
   A need also exists for treating tableware and eating utensils to eliminate pathogens such as  E. Coli  0157:H7,  E. Coli (EXEC),  Salmonella  and other food borne pathogens and yet avoid the aforedescribed disadvantages. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the sterilization apparatus of the invention. 
       FIG. 2  is a perspective view of the position of a spore strip between metal instruments. 
       FIG. 3  is frontal view of a spore strip within its glycine bag. 
       FIG. 4  is a frontal view of the interior of the sterilsation apparatus shown in FIG.  1 . 
       FIG. 5  is a plan view of a sheet of material having fold lines for fabrication into a sterility bag such as that shown in FIG.  5 A. 
       FIG. 5A  shows a sterility bag made from the sheet material of FIG.  5 . 
       FIG. 6  illustrates a temperature indicator for use with the sterility bag of FIG.  5 A. 
       FIG. 7  is a schematic of an alternative embodiment of the sterilsation apparatus of  FIG. 1  for use in continuous sterilization of soil. 
       FIG. 8  shows instruments to be sterilized housed in a sterility bag. 
     SUMMARY OF THE INVENTION 
     The invention advantageously provides a device and method for sterilizing instruments such as medical, dental and veterinarian instruments as well as soil and commodities. The invention advantageously utilizes much less energy than the autoclaves of the prior art and avoids the need for use of purified water during sterilization. The sterilization device of the invention, having the capacity to sterilize a 16 ounce load of instruments, only consumes electrical energy at the rate of about 1346 Watts/Hour over about 4 minutes for a total energy consumption of only 89.73 Watts. This contrasts with autoclaves which use about 2000 Watts/Hour for 60 minutes for a total of 2000 watts for this same volume of instruments. 
     The sterilization devices of the invention are especially suited for operation by automobile or portable generator for use in the field for military and humanitarian field applications (for example military or Red Cross field hospitals). The invention, moreover, is exceedingly safe because it does not use steam, pressure or chemicals. Special electrical outlets or vent systems for removal of toxic vapors also are not needed. 
     The invention advantageously achieves rapid sterilization of instruments such as medical, dental and veterinarian instruments and soil without damage to the instruments. In addition, the sterilization apparatus of the invention can be made in sizes small enough for use in tools and vehicles. The sterilization devices of the invention typically measure about 16.5 inches long, about 10.5 inches wide and about 11.5 inches high and weigh about 20 pounds. Typical autoclaves measure about 24 inches long by 24 inch wide and about 20 inches high and weigh about 80 pounds. The invention can also be employed in equipment which utilized on moving endless belts such as that illustrated schematically in  FIG. 7  which employ conveyor belts to sterilize soil on the belt. 
     In another aspect of the invention, agricultural products are treated to eliminate bacteria therein by exposing those products to infrared radiation at an intensity of about 20-50 kW/m 2  generated by a Nichrome-Quartz heating element. These products include, for example, each side of the product is exposed to infrared radiation for a time sufficient to kill the bacteria as well as to cook the agricultural product. The infrared radiation generated in accordance with the invention is particularly suited for sterilizing hamburger meat, ground meat, beef, poultry, and pork of pathogens such as  Salmonella, E. Coli  0157:H7 and  E. Coli  (EXEC) while also cooking these agricultural products to a flavorful state in about 4 to about 10 minutes. 
     In another aspect of the invention, articles of tableware and eating utensils are treated to eliminate pathogenic bacteria thereon by exposing those articles to infrared radiation at an intensity of about 20-50 kW/m 2  for about 4 minutes to about 20 minutes. Each side of the article is exposed to infrared radiation for a time sufficient to kill bacteria such as  Salmonella, E. Coli  0157:H7,  E. Coli  (EXEC), hepatitis,  bacillus stearothermophilus  and  Bacillus subtilis.    
     Having summarized the invention, it will now be described in detail by reference to the following description. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In a first aspect of the invention as shown in  FIG. 1 , sterilization apparatus  1  is provided for sterilization of objects such as medical, dental and veterinarian instruments, as well as tableware and eating utensils by infrared radiation. Apparatus  1  includes inner cylindrical chamber  9  positioned in outer body  5 . Chamber  9  is maintained in spaced relationship to outer body  5  by supports  20 . Chamber  9  includes elongated support members  42  for receiving and supporting tray  11  therein. Tray  11 , preferably having wire mesh  13  therein, can be placed on support members  42  at a desired position in chamber  9 . Wire mesh  13  has sufficient thickness to support objects for sterilization thereon. Any ambient atmosphere in chamber  9  optionally may be evacuated so that chamber  9  is in a state of negative pressure. 
   A single heating element, preferably upper and lower heating elements  15 A, 15 B, respectively, for generating infrared radiation, are supported in chamber  9  by brackets  7 . Heating elements  15 A, 15 B receive power through leads  17  connected to a suitable electrical power source (not shown). Sterilization apparatus  1  includes door  22  having lock  24  for closing chamber  9  during operation of apparatus  1 . Apparatus  1  may be supported on stands  28 . 
   Heating element  15 A,  15 B, when electrically energized, generate infrared radiation for delivery to instruments  30  placed in tray  11 . Placement of heating elements  15 A, 15 B above and below the instruments provides uniform exposure of the instruments to infrared radiation. Additional heating elements  15 A, 15 B optionally may be placed on the sides of objects  30  to be sterilized. Heating elements  15 A, 15 B preferably are Nichrome-quartz heating elements which include a Nichrome wire housed in a sealed quartz tube. These heating elements typically have a power rating range of about 400 watts to about 800 watts and can generate infrared radiation at an intensity of about 20 KW/m 2  to about 50 KW/m 2 . These elements, when energized to their maximum rated power, operate at about 623° C. to generate infrared radiation at a wavelength of about 3.23 micron at an intensity of about 35.51 KW/m 2 . Nichrome-quartz heating elements which may be used to generate infrared energy include model Q1M138 from THERMAL Innovations Corporation. Other sources of infrared energy which may be used include halogen lamps, and fossil fuels such as butane, propane, diesel fuel, kerosene and gasoline so that the instruments to be sterilized reach a temperature of about 160° C. which is sufficient for sterilization. Where a fossil fuel is employed, it is injected into a tube or hollow panel such as quartz, Pyrex glass, aluminum, steel or ceramics such as mullite. The tubes or panels can be any of a variety of configurations such as round, oval, elliptical, square, or rectangular. During use, the fuel is injected with air into the tube or panel to create a controlled, prolonged combustion therein to heat the tube or panel. The infrared radiation from the tube or panel functions to sterilize the objects  30 . 
   Heating elements  15 A, 15 B are positioned between chamber  9  and tray  11  as shown in FIG.  1 . Chamber  9  is formed from a reflective material such as stainless steel or aluminum, preferably aluminum. Chamber  9  may be flat or it may have curvatures of various radii and configurations such as parabolic and spherical. Preferably, chamber  9  has a spherical radius of curvature of about 3.75 inches. Wire mesh screen  13  can have any mesh size suitable for retaining an  30  to be sterilized thereon. Examples of objects which may be sterilized include but are not limited to medical instruments, dental instruments, veterinarian instruments, soil, and agricultural products such as meats. 
   Tray  11  having wire mesh  13  with objects  30  thereon can be positioned at a wide range of distances between heating elements  15 A, 15 B to achieve a desired intensity of exposure of instruments  30  to infrared radiation sufficient to sterilize any pathogens on instruments  30 . Typically, tray  11  having objects  30  such as medical instruments to be sterilized thereon is located about 2-3 inches, preferably about one inch from heating element  15 A and about 3-5 inches, preferably about one inch from lower heating element  15 B. 
   In accordance with another aspect of the sterilization apparatus of the invention, objects  30  to be sterilized are placed in sterility bag  50  as illustrated in  FIG. 8  prior to treatment with infrared radiation from elements  15 A and  15 B. 
   Sterility bag  50  preferably is re-usable and is formed from Teflon coated fiberglass such as Fluorglas PTFE Coated Glass Fabric 387-3-White Grade from PTFE Coated Fabrics. This material is translucent and enables easy identification of the types of instruments  30  inside sterility bag  50 . The material used to make sterility bag  50  can vary in thickness. Useful nominal thicknesses are about 0.08 mm to about 0.43 mm. The sizes of sterility bag  50  also can vary over a wide range. Useful sizes of sterility bag  50  typically measure about 8.5 inches long by about 5.25 inches wide. 
   During manufacture of sterility bag  50 , sheet material  55  is provided with fold lines  66  as illustrated in FIG.  5 . Sterility bag  50  is made by folding sheet material  55  along lines  66 , and then heat sealing on three sides and leaving an open end having a flap for sealing the opening. Heat sealing can be done by well-known bag-sealing machines which have heat sealing iron elements heated to about 650° F. to about 700° F. An example of such a bag-sealing machine is the impulse heat sealer from Packworld USA, Nazareth, Pa. 18064. 
   Sterility bag  50  receives objects  30 . After objects  30  are placed in sterility bag  50  through opening  70 , flap  75  is sealed over the opening by spring loaded bail type clip  32 . Clip  32  can vary in size according to the dimensions of sterility bag  50 . The spring loading of clip  32  is sufficient to ensure that clip  32  remains on sterility bag  50  if sterility bag  50  is moved. The jaws of clip  32  also can be made with complementary wavy surfaces to ensure sealing. The jaws of clip  32  also can have pins which extend from one jaw of the clip through the other jaw and corresponding holes in the bag. Sealing of sterility bag  50  by clip  32  ensures that instruments  30  are maintained in a sterile condition inside sterility bag  50  after sterilsation. 
   Sterility bag  50  can be employed with temperature indicator  38  such as that shown in  FIG. 6  to measure the temperature of objects  30  in sterility bag  50 . Temperature indicator  38  may be chosen from a variety of commercially available products. A product that is particularly useful as temperature indicator  38  is the Single-Point Irreversible Temperature Indicator from Omega Engineering, Inc., PO Box 4047, Stamford, Conn. 06907. 
   During operation of apparatus  1 , objects  30  such as medical, dental and veterinarian instruments are first placed in tray  11  having wire mesh  13  therein. Tray  11  having the objects  30  then is positioned in chamber  9 . Door  22  then is secured to close chamber  9 . Heating elements  15 A, 15 B then are energized to emit infrared radiation. Objects  30  are exposed to infrared radiation generated by elements  15 A, 15 B in chamber  9  to cause objects  30  to reach a temperature sufficient for sterilization. Advantageously, sterilization is accomplished with the invention without having to heat the ambient atmosphere of chamber  9  to a temperature sufficient for sterilization. Temperatures for sterilization vary from about 160° C. to about 300° C. depending on the object to be sterilized. In the instance of objects such as metallic medical, dental or veterinarian instruments, the temperature for sterilization is preferably about 210° C. 
   Infrared radiation from heating elements  15 A, 15 B is applied to objects  30  to cause them to reach at least 160° C., i.e., the temperature sufficient to kill  Bacillus stearothermophilus. Bacillus stearothermophilus , the pathogen that the United States Food and Drug Administration FDA employs to test autoclaves, is the hardest known pathogen for an autoclave to kill. Many other pathogens are killed at much lower temperatures. 
   To evaluate the ability of the apparatus and method of invention to achieve rapid sterilization of objects  30 , spore strip  34  having  bacillus stearthermophilus  thereon and housed in glycine bag  40  is secured between objects  30  (stainless steel formks) by clip  32  as shown in FIG.  2 . Spore strip  34  housed in glycine bag  40  is available as a component of the Spor View Culture Set CS-100 from SPS Medical Corporation, Rochester, N.Y. 
   Probe  36  of a commercially available instant-read type digital thermometer  38  is inserted between objects  30  to measure the temperature in the region between objects  30  where glycine bag  40  having spore strip  34  is located. The time periods of irradiation, and the temperature of the spore strip  34  are recorded. All tests are initiated from cold starts. 
   After exposing spore strip  34  to infrared radiation from elements  15 A, 15 B, spore strip  34  is removed from glycine bag  40  and is inserted into a test tube having evaluation liquid as supplied with the above-mentioned SporView Culture Set CS-100. Strip  34  is incubated in the test tube at 56° C. for  48  hours. After incuabtion, if the color of the evaluation liquid changes to yellow, then  Bacillus stearothermophilus  survivors exist on spore strip  34 . If the color remains unchanged, then no survivors of  Bacillus stearothermophilus  exist on spore strip  34 . 
   The results are shown in Table 1. All results are for a 16 ounce load of objects  30  (stainless steel instruments). Generally, a heavier load of objects  30  requires more time to reach the desired temperature range of 160° C. to 235° C. For example, the time difference for a 2.5-oz load of stainless steel objects to reach its target temperature and for a 16-oz load stainless steel objects to reach that same target temperature is about 30 seconds. 
   
     
       
             
             
             
             
           
             
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
               Time 
                 
               Color of Evaluation 
                 
             
             
               (Seconds) 
               Temp. ° C. 
               Liquid 
               Result* 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               0.0 
               26.0 
               Yellow 
               Survivors 
             
             
               30.0 
               34.0 
               Yellow 
               Survivors 
             
             
               60.0 
               58.0 
               Yellow 
               Survivors 
             
             
               90.0 
               87.0 
               Yellow 
               Survivors 
             
             
               120.0 
               117.0 
               Yellow 
               Survivors 
             
             
               150.0 
               144.0 
               Yellow 
               Survivors 
             
             
               180.0 
               168.0 
               Unchanged 
               No Survivors 
             
             
               210.0 
               190.0 
               Unchanged 
               No Survivors 
             
             
               240.0 
               209.0 
               Unchanged 
               No Survivors 
             
             
               270.0 
               216.0 
               Unchanged 
               No Survivors 
             
             
               300.0 
               214.0 
               Unchanged 
               No Survivors 
             
             
               330.0 
               207.0 
               Unchanged 
               No Survivors 
             
             
               360.0 
               199.0 
               Unchanged 
               No Survivors 
             
             
               390.0 
               191.0 
               Unchanged 
               No Survivors 
             
             
               420.0 
               183.0 
               Unchanged 
               No Survivors 
             
             
                 
             
           
        
       
     
   
   In order to measure the temperature of instruments  30 , probe  36  of instant-read dial type digital thermometer  38  is inserted between instruments  30  to measure the temperature of the region between instruments  30  where spore strip  34  housed in glycine bag  40  is located. Instruments  30  are placed onto wire mesh  13  in tray  11 . Heating elements  15 A, 15 B are energized to their maximum power rating of 650 watts for four minutes, and the temperature is read every minute. After four minutes, heating elements  15 A,  15 B are de-energized and the temperature is read every minute until seven minutes. The temperatures of instruments  30  are shown in Table 2. In Table 2, the weight of the instruments  30  in tray  11  is 16 ounces. 
   
     
       
             
             
             
           
             
             
             
           
         
             
                 
               TABLE 2 
             
             
                 
                 
             
             
                 
               Time 
               Temp. of Instruments 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
                 
               0.0 
                     26 (° C.) 
             
             
                 
               60.0 
                58.0 
             
             
                 
               120.0 
               117.0 
             
             
                 
               180.0 
               168.0 
             
             
                 
               240.0 
               209.0 
             
             
                 
               300.0 
               214.0 
             
             
                 
               360.0 
               199.0 
             
             
                 
               420.0* 
               183.0 
             
             
                 
                 
             
             
                 
               *Power turned off.  
             
           
        
       
     
   
   As a comparison, and in order to determine the role, if any, that the temperature of the air in chamber  9  has in sterilization of objects  30 , heating elements  15 A,  15 B are energized to their full power rating of 650 watts for one minute to reach an operating temperature of 623° C. without tray  11  or instruments  30  present in chamber  9 . After the power is turned off, door  22  of apparatus  1  is opened and probe  36  of instant-read dial type digital thermometer  38  is immediately inserted into chamber  9 . Door  22  then is closed immediately to measure the air temperature. Apparatus  1  then is cooled to room temperature. This same procedure is repeated for operation times of 2 minutes, 3 minutes and 4 minutes. After 4 minutes the power is turned off. The temperature inside the chamber is read every minute until 7 minutes. The results are shown in Table 3. 
   
     
       
             
             
             
           
             
             
             
           
         
             
               TABLE 3 
             
             
                 
             
             
               Time 
               Temp. of 
               Temp. of Air In 
             
             
               (Sec) 
               Instruments 
               chamber 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               0.0 
                    26° C. 
                    21° C. 
             
             
               60.0 
                58 
               102 
             
             
               120.0 
               168 
               115 
             
             
               180.0 
               214 
               121 
             
             
               240.0 
               209 
               124 
             
             
               300.0 
               214 
               105 
             
             
                 
             
             
               *Power turned off  
             
           
        
       
     
   
   The results in Table 3 show a substantial difference between the temperature of the ambient atmosphere inside chamber  9  and the temperatures of instruments  30  under the same energy and time conditions. After 4 minutes of irradiation as described above, the temperature of the instruments  30  is 209° C. whereas the ambient temperature in chamber  9  is 124° C. After 5 minutes, the temperature of instruments  30  is 214° C. whereas the temperature inside chamber  9  is 105° C. 
   As can be seen from Table 3, the temperature of the ambient air inside chamber  9  never reached a level high sufficient to sterilize  Bacillus stearothermophilus . The temperature of instruments  30 , however, reached a level more than sufficient to sterilize  Bacillus stearothermophilus.    
   Sterilization of Instruments Without Use of a Sterility Bag. 
   In order to measure the temperature of instruments  30  (dental hand pieces) being sterilized without use of a sterility bag, probe  36  of instant-read dial type digital thermometer  38  is inserted into the hand piece to measure the temperature inside the hand piece where spore strip  34  in glycine bag  40  is located. A 16 oz. load of instruments  30  is placed into tray  11  and placed into chamber  9 . Heating elements  15 A, 15 B are energized to 650 watts for 4 minutes, and the temperature of the dental hand pieces is read every minute. After 4 minutes, heating elements  15 A, 15 B are de-energized and the temperature is read every minute until 10 minutes. The temperatures of the dental hand pieces are shown in Table 4. The presence of  Bacillus Stearothermophilus  survivors on spore strip  34  is determined as described above. The results are shown in Table 4. 
                                         TABLE 4               Time               (Sec.)   Temp. of Instruments   Result                                0        23° C.   Survivors       30    24   Survivors       60    33   Survivors       90    51   Survivors       120    75   Survivors       150   101   Survivors       180   127   Survivors       210   151   Survivors       240   173   No Survivors       270   189   No Survivors       300   193   No Survivors       330   190   No Survivors       360   184   No Survivors       390   176   No Survivors       420   168   No Survivors       450   153   No Survivors       480   125   No Survivors       510    98   No Survivors       540    77   No Survivors       570    60   No Survivors       600    48   No Survivors                    
Sterilization of Objects Within Sterility Bag
 
   In order to measure the temperature of the dental hand pieces in sterility bag  50 , probe  36  of an instant-read dial type digital thermometer  38  is inserted inside the dental headpiece to measure the temperature inside the piece where a spore strip  34  housed in glycine bag  40  is located. The hand pieces are placed onto mesh  13  in tray  11  and placed into chamber  9 . Heating elements  15 A,  15 B are energized to their maximum power rating of 650 watts for 4 minutes, and the temperature is read every minute. After 4 minutes, the heating elements  15 A, 15 B are de-energized and the temperature is read every minute until 20 minutes. The temperatures of the hand pieces are shown in Table 5. In Table 5, the weight of the hand pieces inside sterility bag  50  is 10.5 ounces. The presence of  Bacillus Stearothermophilus  survivors on spore strip  34  is determined as described above. The results are shown in Table 5. The data in Tables 4 and 5 show that sterilization times are not extended when using sterilization bag  40 . 
                                         TABLE 5               Time (sec)   Temp (° C.)   Result                                0   25   Survivors       30   26   Survivors       60   34   Survivors       90   53   Survivors       120   80   Survivors       150   105   Survivors       180   134   Survivors       210   162   No Survivors       240   190   No Survivors       270   212   No Survivors       300   222   No Survivors       330   224   No Survivors       360   221   No Survivors       390   216   No Survivors       420   211   No Survivors       450   204   No Survivors       480   195   No Survivors       510   185   No Survivors       540   174   No Survivors       570   163   No Survivors       600   153   No Survivors       630   143   No Survivors       660   135   No Survivors       690   127   No Survivors       720   122   No Survivors       750   117   No Survivors       780   113   No Survivors       810   109   No Survivors       840   105   No Survivors       870   101   No Survivors       900   97   No Survivors       930   94   No Survivors       960   91   No Survivors       990   88   No Survivors       1020   85   No Survivors       1050   82   No Survivors       1080   79   No Survivors       1110   76   No Survivors       1140   73   No Survivors       1170   71   No Survivors       1200   69   No Survivors                    
Sterilization of soil infected with  Fusarium , Trichderma and  Pythium    
   In this aspect, the apparatus and method of the invention are used to sterilize soil samples infected with  Fusarium , Trichderma and  Pythium  which were obtained from the United States Dept. of Agriculture Forest Service, Technology &amp; Development Center, Fort Missoula, Missoula, Mont. The soil samples contained 274.3 cfu/g  Fusarium,  68.6 cfu/g Trichderma and 13.7 cfu/g  Pythium . These soil samples are treated with infrared radiation from heating elements  15 A, 15 B in chamber  9  of apparatus  1 . The soil samples are spread onto tray  11  to form a layer of about ⅛ inch to about ¼ inch thick. Tray  11  having the soil sample is placed into chamber  9 . The soil sample is 3.25 inches from heating element  15 A and 1.25 inches from heating element  15 B. Heating elements  15 A, 15 B are energized to emit infrared radiation at an intensity of 28.8 KW/m 2 . 
   Six soil samples are treated using differing time intervals of exposure to the infrared radiation from elements  15 A,  15 B as above. The soil samples are returned to the United States Dept. of Agriculture Forest Service, Technology &amp; Development Center, Fort Missoula, Missoula, Mont. where they are evaluated for residual  Fusarium, Trichoderma  and  Pythium . Evaluation for presence of  Fusarium, Trichoderma  and  Pythium  entails oven drying a 5 gram sample of the irradiated soil at 100° C. for at least 24 hours or until the sample weight stabilizes and all excess moisture is removed. Oven-dry weight is calculated to provide a standard for comparison. For assay of  Fusarium  and  Trichoderma,  0.05 g of field-moist soil is combined with 10 ml of 0.3% water agar and thoroughly mixed to provide a liquid mixture. One ml of the liquid mixture is placed on each of three plates of selective agar medium and spread uniformly. The plates are incubated for 5 days at about 24° C. under diurnal cycles of cool, fluorescent light.  Fusarium  and  Trichoderma  colonies are identified by their morphology on the selective medium and populations calculated.  Fusarium  isolates are transferred to carnation leaf agar and potato dextrose agar for identification using the taxonomic scheme of Nelson disclosed in  Fusarium  Species: An Illustrated manual for Identification, Pennsylvania State University Press, University park, PA Page 193(1983). For assay of  Pythium  populations, 0.5 g of soil is combined with 10 ml of 0.3% water agar. One ml of solution is placed on each of three plates of another selective medium of V-8 juice agar amended with pimaricin, rifamycin, ampicillin and pentchloronltrobenze as disclosed by James et al. in Soil Assays for  Fusarium  and  Pythium  in fumigated soils, Forest Pest Management, Nursery Disease Notes, No. 16, Page 3(1985). Plates are incubated in darkness at about 24° C. for 3 days.  Pythium  colonies are identified on the basis of their diameter after three days (15-20 mm), their feather margin, and their growth within the Agar medium rather than superficially on the surface of the agar medium. It is assumed that each colony originates from an individual propagule. Populations are expressed as colony-forming units (cfu) per gram of oven dried soil. 
   The results, as shown in Table 6, show that when the soil samples are subjected to infrared radiation at an intensity of 28.8 kW/m 2  in the apparatus of the invention completely kill  Fusarium  and Trichderma in the soil samples is achieved after 27 seconds exposure, and that complete kill of  Pythium  is achieved after 20 seconds exposure. 
   In an alternate embodiment of this aspect of the invention, the soil to be sterilized can be placed on a continuous belt 90 and exposed to infrared radiation as shown schematically in FIG.  7 . 
   
     
       
             
             
             
             
             
             
           
             
             
             
             
             
             
           
         
             
               TABLE 6 
             
             
                 
             
             
                 
                 
                 
                 
               Intensity of 
                 
             
             
               Time 
               Residual 
               Residual 
               Residual 
               Infrared 
               Soil 
             
             
               (Sec.) 
               
                 Fusarium 
               
               
                 Trichderma 
               
               
                 Pythium 
               
               Radiation 
               Volume 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               20 
               136.2 
               408.6 
               0 
               28.8 
               ½ Pint 
             
             
               23 
               205.9 
               0 
               0 
               28.8 
               ½ Pint 
             
             
               24 
               68.1 
               68.1 
               0 
               28.8 
               ½ Pint 
             
             
               27 
               0 
               0 
               0 
               28.8 
               ½ Pint 
             
             
               55 
               0 
               0 
               0 
               28.8 
               ½ Pint 
             
             
               66 
               0 
               0 
               0 
               28.8 
               ½ Pint 
             
             
               Control 
               274.3 
               68.6 
               13.7 
               No treatment 
               ¾ Pint 
             
             
                 
             
           
        
       
     
   
   In another embodiment, and to show the ability of the invention to eradicate anthrax spores from soil,  Bacillus subtilis  is placed inside bacterial sterilization monitor spore strips from SPS Medical Corporation.  Bacillus subtilis  was chosen because the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick regards  Bacillus subtilis  as a surrogate for anthrax. The spore strips having  bacillus subtilis  thereon are inserted between two stainless steel metal blades. The metal blades were tightly fitted together prior to sterilization. The spore strips located between the metal blades are exposed to infrared radiation generated by the Nichrome-quartz heating elements at an intensity of 35.51 KW/m 2  for 4-5 minutes. After irradiation, the spore strips were incubated at 37° C. for 96 hours in a test tube filled with color indicator liquid. The color indicator liquid is included in the Sporview Culture Set available from SPS Medical, Rochester, N.Y. All tests were initiated from cold starts. The presence of  bacillus subtilis  survivors on the irradiated spore strip is determined using the procedure described above as described above in connection with  bacillus stearothermophilus . The results are shown in Table 7. 
   The results in Table 7 show that  bacillus subtilis  is eradicated after 3.5 minutes. 
   
     
       
             
             
             
           
             
             
             
           
         
             
               TABLE 7 
             
             
                 
             
             
               Time 
                 
               Residual 
             
             
               (min:sec) 
               Temp ° C. 
               
                 Bacillus Subtilis 
               
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               0:00 
               26 
               Survivors 
             
             
               0:30 
               34 
               Survivors 
             
             
               1:00 
               58 
               Survivors 
             
             
               1:30 
               87 
               Survivors 
             
             
               2:00 
               117 
               Survivors 
             
             
               2:30 
               144 
               Survivors 
             
             
               3:00 
               168 
               Survivors 
             
             
               3:30 
               190 
               No Survivors 
             
             
               4:00 
               209 
               No Survivors 
             
             
               4:30 
               216 
               No Survivors 
             
             
               5:00 
               214 
               No Survivors 
             
             
               5:30 
               207 
               No Survivors 
             
             
               6:00 
               199 
               No Survivors 
             
             
               6:30 
               191 
               No Survivors 
             
             
               7:00 
               183 
               No Survivors 
             
             
                 
             
           
        
       
     
   
   The invention, in addition to rapid sterilization, makes energy transfers for sterilization more effective and treatment cycles shorter without toxicity or radioactivity. The invention is environmentally safe and does not damage the Ozone layer. 
   The invention enables planting of, for example, tomatoes, strawberries, peppers, nursery trees, carrots, seedbeds, lettuce, tobacco, sweet potatoes, melons, cucumbers, eggplants, cantaloupe, cauliflower, broccoli, onions and other crops in soil immediately after the soil is sterilized by the apparatus and method of the invention. This is in contrast to a waiting period of three weeks when planting in soil that has been sterilized with Methyl Bromide. 
   The small size and lightweight of the apparatus of the invention in combination with its low energy consumption, makes the invention uniquely suitable for use in field hospitals to sterilize medical, dental and veterinary instruments. The apparatus of the invention can be scaled to large sizes when employed in high volume applications such as sterilization of soil. 
   The invention, due in part to its ability to achieve rapid sterilization in less than 3.5 minutes can be used to prevent transmissions of mad cow disease via medical, dental and veterinary instruments. Both the temperature range and time cycle of the apparatus may be varied to eliminate contagion believed to contribute toward Alzheimer&#39;s Disease, Bovine Spongiform Encephalopathy (BSE—Mad Cow Disease), Kuru, Gertsmann-Straussler-Scheinker Disease, Fatal Familial Insomnia, Creutzfeldt-Jakob Disease (CJD), a new variant of CJD and harmful prions on medical, dental and veterinary instruments (better than 8.0 log). 
   In another aspect of the invention, agricultural products, preferably hamburger meat, ground meat, beef, poultry, and pork are treated with infrared radiation in apparatus  1  using infrared radiation generated by heating elements  15 A,  15 B. Preferably, the heating element is a Nichrome wire housed in a quartz tube. The Nichrome heating element also may be housed in a ceramic tube such as mullite. 
   In an illustrative aspect of the invention, a 4 oz. Hamburger patty is placed on tray  11  having wire mesh  13  therein. Tray  11  is inserted into apparatus  1  so that the patty is located 3.25 inches from top heating element  15 A and 1.25 inches from lower heating element  15 B. Elements  15 A, 15 B are energized to 650 watts at 123 V each to generate infrared radiation at an intensity of 36.83 KW/m 2  onto the hamburger patty for a time sufficient to reach a sterilization temperature of about 158° F. to about 176° F. 
   The temperature inside the hamburger patty was measured with probe  36  of instant-read dial type digital thermometer  36  inserted into the middle of the hamburger patty. The probe and thermometer also are used to check temperatures throughout the patty. After subjecting the hamburger patty to the infrared radiation as described above for 270 sec., the temperature in every portion of the hamburger patty was 160° F. or above. The results of treatment of the hamburger patties cooked to the medium rare state are shown in Table 8. 
   
     
       
             
             
             
           
             
             
             
           
         
             
                 
               TABLE 8 
             
             
                 
                 
             
             
                 
               Time 
               Temp ° F. 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
                 
                0 sec. 
               47 
             
             
                 
                30 
               65 
             
             
                 
                60 
               86 
             
             
                 
                90 
               103 
             
             
                 
               120 
               118 
             
             
                 
               150 
               130 
             
             
                 
               180 
               141 
             
             
                 
               210 
               148 
             
             
                 
               240 
               155 
             
             
                 
               270 
               162