Description:TECHNICAL FIELD
[0001] The present invention is related to methods of sterilization or pasteurization of articles such as food products using elevated pressure and temperature, and apparatus thereof.
BACKGROUND
[0002] Fluid sterilization plays an important role across a wide spectrum of applications, to include personal, industrial, manufacturing, and medical applications. Generally speaking, sterilization is identified as a process that will make an object free of any living transmissible agent (such as fungi, bacteria, viruses, spore forms, microorganisms, prions, etc.). The object to be sterilized may be any of several types, including surfaces, a volume of fluid, or other materials in use or to be used in human or animal activities. Effectiveness of sterilization is generally referenced via a sterility assurance level.
[0003] High pressure processing (HPP) of food is a non-thermal sterilization process, which retains the food quality of freshness and reduces damage to nutrients such as vitamins. HPP processing can be used not only for preservation but also for changing the physical and functional properties of foods. HPP is used for treating food products which are currently available in the market including juices, jams, jellies, yogurts, meat, and seafood such as oysters.
[0004] Furthermore, in the case of solid or semisolid products, during the rapid heating phase the product may overheat, particularly on its external surface, with consequent damage to its organoleptic qualities..
[0005] Therefore, there is a need of process and apparatus which overcomes the aforementioned problems.
SUMMARY
[001] Embodiments of the present disclosure present technological improvements as solutions to one or more of the above-mentioned technical problems.
[002] Before the present subject matter relating to method and system for processing food products, it is to be understood that this application is not limited to the particular system described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the implementations or versions or embodiments only and is not intended to limit the scope of the present subject matter.
[003] This summary is provided to introduce aspects related method and system for processing food products. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the present subject matter.
[004] In one embodiment, a method for sterilizing an article, comprising the step of heating the article and/or medium associated or in communication with the article within a confined volume sufficiently that expansion of the article and/or of the medium subjects the article to a pressure sufficient when combined with the elevated temperature to pasteurize or sterilize the article. In an another embodiment of the present invention, he article will be a food product. Where the article is a food product it is preferably heated to a temperature below about 140° C., (usually used in a short time-high temperature sterilization process) more preferably below 120° C., (usually employed in the in-can sterilization) or at normal sterilization temperature but for shorter time to minimise damage to the product and maximise retention of food quality which may otherwise occur.
[005] In another embodiment, the system comprises a series of tubular elements, consisting of a small-diameter, cylindrical casing, joined together by connecting sections with airtight doors, the products being introduced into or extracted from these elements by means of conveyor devices, for example, belt or chain conveyors. The plant may consist of a plurality of sections functioning in parallel, inside each of which the complete treatment of the products to be pasteurized or sterilized takes place.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[006] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference features and modules.
[007] Figure 1 illustrates a schematic of one implementation of the invention.
[008] Figure 2 illustrates a schematic of a further implementation of the invention.
[009] Figure 3 illustrates a schematic, plan view of a plant according to the invention for the sterilization or pasteurization, in three phases, of liquid substances.
[0006] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0007] The invention will now be described with reference to the accompanying drawings and embodiments which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
[0008] One or more embodiments are provided so as to thoroughly and fully convey the scope of the present invention to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present invention. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present invention. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
[0009] The terminology used, in the present invention, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present invention. As used in the present invention, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present invention is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
[0010] Figure 1 illustrates a schematic of one implementation of the invention.
[0011] The “article” to be processed, includes liquid products such as juice, milk, or honey for example, a paste such as tomato paste, or any other pumpable food or non-food product is pumped into tubes 1 of a heat exchanger 2, from a bulk supply schematically illustrated at 4 (or typically alternatively an upstream stage in a food processing plant) by a food grade pump 3, to completely fill the heat exchanger tubes (absent of any air or other gas). When the heat exchanger tubes have been filled with the product, inlet and outlet valves 5 a and 5 b (the latter open to allow the escape of any air), which may be manual or solenoid-controlled valves for example, are closed to isolate the product within the heat exchanger. Hot water, steam, oil, or other heating medium is circulated in the outer jacket around the tubes 1 of the heat exchanger containing the product, and heats the product within the heat exchanger tubes 1 to a predetermined temperature. Heating medium inlet and outlet 7 a and 7 b to the heat exchanger 2 outer jacket are schematically illustrated as shown. The product resident within the heat exchanger tubes 1 is heated causing expansion of the product within the confined volume of the heat exchanger tubes (with inlet and outlet valves 5 a and 5 b closed), so that the product is subjected to a pressure increase within the heat exchanger, which combined with the elevated temperature, is sufficient to sterilise or pasteurise the product. The temperature to which the product is heated is selected to sterilise or pasteurise the product, with minimum damage to the quality of the product where the product is a food product for example. Subsequently valves 5 a and 5 b are opened and the product is pumped from the heat exchanger, allowing the second batch of fresh product to enter for treatment. It has been found that typically heating a liquid food product to a temperature approaching 100° C. will generate pressure of about 700 bar. With a treatment time of about 90 minutes a 4-log reduction of the B. stearothermophilus may be achieved. Thermal sterilization at ambient pressure cannot be achieved at 100° C. as the log reduction will be very small. At temperatures above 100° C., the log-reduction of the B. stearothermophilus has increase by factor of 5 to 10 by applying the method of this invention, which includes measurements conducted at high temperatures. At temperatures below 100° C., the difference in the log-reduction between the two types of treatment is even bigger.
[0010] Figure 2 illustrates a schematic of a further implementation of the invention. A product F which may for example be a solid food product such as meat or seafood packed in an evacuated plastic pouch for example, or alternatively a liquid or paste food product in an evacuated plastic pouch, or a non-food product, is placed within vessel or chamber 10 connected to heat exchanger 2, through a door (not shown) in vessel or chamber 10. With valves 5 a and 5 b open a liquid which may be simply water for example or possibly a medium with a higher thermal expansion co-efficient, is pumped into the interior of the heat exchanger and the chamber 10 connected to the heat exchanger to completely fill the heat exchanger and the chamber 10 around the product F (any air or other gas is evacuated or expelled). Valves 5 a and 5 b are then closed. Hot water is circulated within the outer jacket of the heat exchanger to heat the high expansion liquid medium within the heat exchanger and chamber 10, generating pressure within the heat exchanger and chamber 10 on the product F, which is sufficient when combined with the elevated temperature to sterilise or pasteurise the product. The treatment chamber may optionally also be heated via for example another surrounding water jacket, resistance heating or microwave heating. Subsequently valves 5 a and 5 b are opened to release the pressure so that the product F may be removed by opening the chamber 10.
[0011] Figure 3 illustrates a schematic, plan view of a plant according to the invention for the sterilization or pasteurization, in three phases of liquid substances. The plant includes a first tubular element 2 for the rapid heating of the product, made up of a plurality of small-diameter, cylindrical tubular sections 2a, substantially the same as each other and of an end tubular section 2b, with curved axis and angular development up to 180° and of a diameter substantially equal to that of the cylindrical tubular sections 2a, the said end section 2b connecting the said first tubular element 2 and a second tubular element 3 in which the phase of the maintenance of the final pasteurization or sterilization temperature is carried out.
[0012] The second tubular element 3, similarly to the tubular element 2, is also made up of a plurality of small-diameter, cylindrical tubular sections 3a, which are substantially the same as each other, and of a end section 3b, tubular with curved axis and angular development up to 180°, which connects the second tubular element 3 to a third tubular element 4 in which cooling of the product after the pasteurization or sterilization treatment is carried out.
[0013] The third tubular element 4 is made up of a plurality of small diameter cylindrical tubular sections 4a, substantially the same as each other.
[0014] The products to be sterilized or pasteurized, packaged in sealed containers of materials transparent to microwaves, are inserted in the plant 1 and removed from it by means of a first conveyor device 5 and a second conveyor device 6, for example a conveyor belt.
[0015] The first conveyor device 5 inserts the containers 49 in an entrance element 7, which on the inside has opening and airtight closing devices (not shown), which is communicating with the first cylindrical, tubular section 2a of the first tubular element 2.
[0016] The second conveyor device 6 collects the containers 49 from an exit element 10, which on the inside has opening and airtight closing devices (not shown), which is communicating with the last cylindrical, tubular section 4a of the third tubular element 4.
[0017] A first connecting element 8 is inserted between the end section 2b of the first tubular element 2 and the second tubular element 3 of plant 1, a second connecting element 9 is inserted between the end section 3b of the second tubular element 3 and the third tubular element 4 of plant 1.
[0018] Elements 8 and 9, which are analogous to the entrance element 7 and to the exit element 10, both have opening and airtight closing devices.
[0019] It should be noted that the curved tubular sections 2b, 3b may be omitted, if the space available for the installation of the plant 1 enables the tubular elements 2, 3 and 4 to be positioned in line.
[0020] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
, Claims:We claim:
1. A method for sterilizing or pasteurizing food products, comprising the steps of:
a. placing the food products in a pressure vessel;
b. sealing the pressure vessel;
c. raising the pressure within the pressure vessel to a predetermined elevated pressure;
d. simultaneously elevating the temperature within the pressure vessel to a predetermined elevated temperature; and
e. maintaining the elevated pressure and temperature within the pressure vessel for a predetermined period to achieve sterilization or pasteurization of the food products.

2. The method of claim 1, wherein the predetermined elevated pressure is in the range of 50 to 200 psi.

3. The method of claim 1, wherein the predetermined elevated temperature is in the range of 121°C to 150°C.

4. The method of claim 1, wherein the predetermined period for maintaining the elevated pressure and temperature is in the range of 5 to 60 minutes.

5. An apparatus for sterilizing or pasteurizing articles, comprising:
a. a pressure vessel having an interior chamber for holding the articles;
b. a sealing mechanism for hermetically sealing the pressure vessel;
c. a heating element for elevating the temperature within the pressure vessel;
d. a pressure control system for raising and maintaining the pressure within the pressure vessel to a predetermined elevated pressure; and
e. a temperature control system for simultaneously elevating and maintaining the temperature within the pressure vessel at a predetermined elevated temperature.
6. The apparatus of claim 5, further comprising a timer or controller for regulating the duration of the elevated pressure and temperature treatment.

7. The apparatus of claim 5, wherein the pressure control system includes a pressure relief valve for releasing excess pressure.

8. The apparatus of claim 5, wherein the temperature control system includes one or more temperature sensors for monitoring the temperature within the pressure vessel.

9. The apparatus of claim 5, wherein the sealing mechanism comprises a gasket or O-ring for creating a hermetic seal.

10. The apparatus of claim 5, further comprising a cooling system for rapidly reducing the temperature within the pressure vessel after the sterilization or pasteurization process.