“PROCEDURE FOR SANITIZATION AND MICROBIOLOGICAL STABILIZATION OF LIQUID EGG WHITE STORED AT ROOM TEMPERATURE”

Description

Patent application for INDUSTRIAL INVENTION entitled: “PROCEDURE FOR SANITIZATION AND STABILIZATION MICROBIOLOGY OF LIQUID EGG WHITE STORED AT TEMPERATURE ENVIRONMENT" On behalf of: SANOVO TECHNOLOGY ITALIA Srl Inventors: Giosuè CASAGRANDE; Mauro BALASSO; Paolo BONATO; Roberto COLAVITTI DESCRIPTION * * * * * Technical field The present invention falls within the technical sector of egg products and, more specifically, specifically, in the technical sector of conservation and storage of goods easily perishable foods such as egg products. 5 In particular, the invention relates to a process for sanitization and for the microbiological stabilization of liquid egg white that can be stored at room temperature environment. * * * * * State of the art 10 To date, industrial plants for the production and packaging of egg white liquid foresees the application of different heat treatment phases with the aim of minimize risks to consumer health, in particular manufacturing processes thermal pasteurization under conditions lethal for normally present pathogens in the egg. In fact, as is known, food products contain various microorganisms, 15 such as bacteria in vegetative form, fungi and yeasts, which in the case of a bad preservation of the above mentioned food products can proliferate, develop and, therefore, be pathogenic for final consumers. Generally, the most widely used heat treatment process is the one of pasteurization which, in short, involves carrying out a heating 20 of the product for a pre-established time interval and temperature value in order to to allow the elimination of most microorganisms that can be present, especially pathogenic bacteria. The pasteurization process, moreover, occurs at temperatures lower than those that would cause the denaturation of the albumen proteins, so as to preserve their organoleptic characteristics. However, at in order to ensure the elimination of some extremely dangerous pathogenic bacteria, 5 like salmonella, the pasteurization process is usually performed in boundary conditions such as to determine some protein denaturations with the consequent impairment of the chemical-physical properties of the egg product. This means that the egg white heat-treated by pasteurization will be free of pathogenic microorganisms, but still populated by microorganisms 10 heat-resistant products that contribute to the sensory deterioration of the product. Therefore, egg white heat-treated by pasteurization must be necessarily introduced into the so-called "cold chain" for ensure its correct storage in refrigerators set at lower temperatures at 5°C. The cold chain, therefore, will lead to an increase in transport difficulties 15 and conservation, as well as the related final costs of the product. In addition, since it is not completely free of heat-resistant microorganisms, the shelf life the shelf life of liquid egg white is limited to a few weeks from its packaging, provided it is stored correctly. In the case of egg white and egg products, unlike milk, it is not possible 20 carry out sterilization processes at temperatures that guarantee total elimination of pathogenic and heat-resistant microorganisms for the aforementioned preservation of organoleptic characteristics. * * * * * Summary 25 In this context, the technical task underlying the present invention is to propose a procedure for the stabilization of egg white at room temperature liquid that overcomes the drawbacks of the prior art mentioned above. In particular, it is an object of the present invention to provide a method for the stabilization of the liquid egg white at room temperature in order to guarantee a 30 increase in the shelf life of liquid egg white, i.e. the so-called “shelf life”. Another object of the present invention is to provide a method for the stabilization of the liquid egg white at room temperature which allows a reduction of consumption and, therefore, of overall production costs. Therefore, specifically, the invention aims to eliminate the use of the so-called "chain of cold” which, today, is essential in order to guarantee a correct 5 conservation and consumption of liquid egg white produced with known processes. A further object of the present invention is to provide a process for the stabilization of the liquid egg white at room temperature which allows for the execution of a less expensive packaging, in economic and practical terms, of the packaging with aseptic packaging machine. 10 The specified technical task and the specified purposes are substantially achieved by a process for sanitization and microbiological stabilization of liquid egg white stored at room temperature, which includes the technical characteristics set out in the independent claim. The claims employees correspond to further advantageous aspects of the invention. 15 It should be appreciated that this summary introduces a selection of concepts in the form simplified, which will be further developed in the detailed description of reported below. The invention is directed to a process for sanitization and stabilization microbiological analysis of liquid egg white stored at room temperature which includes 20 the following operational phases: - prepare a pre-established quantity of liquid egg white; - perform an initial heat treatment on the egg white in order to eliminate part of it of the microorganisms present in the egg white and activate the germination of the spores; - incubate the egg white at a temperature between 30 and 40 °C for a 25 time interval between 16 and 26 hours for the germination of spores and, in addition, for the resumption of bacterial growth; - perform a second heat treatment of the egg white equivalent to the first heat treatment to eliminate bacteria present in the egg white resulting from spores and who have resumed vital activity; 30 - perform an isothermal treatment at a temperature between 42 and 52 °C for an isothermal treatment time interval between 7 and 17 hours so to eliminate bacteria present in the egg white that were not eliminated by the second treatment thermal; - perform a third heat treatment of the egg white in order to eliminate the bacteria resistant bacteria present in the egg white and not eliminated by the first and second treatments thermal. 5 - preferably but not necessarily, carry out a packaging temperatures between 48°C and 58°C. In detail, each treatment phase thermal is composed of two distinct heating operations: a first heating and a second heating. In relation to the first and second heat treatment phases, the first operation 10 heating is performed at a temperature value between 52 and 58 °C and, furthermore, for a time interval of less than 300 seconds. The second heating operation, in relation to the first and second phases heat treatment, is performed at a temperature value between 59 and 62 °C and, moreover, for a time interval of less than 40 seconds. 15 Differently, the first heating operation of the third treatment phase thermal is performed at a temperature value between 50 and 55 °C and, furthermore, for a time interval of less than 300 seconds. The second heating operation, Instead, it is performed at a temperature value between 53 and 58 °C for a time interval less than 40 seconds. 20 In this way, the stabilization procedure just described is advantageously able to allow the preparation of stable liquid egg white at room temperature, i.e. a liquid egg white that can be stored at room temperature avoiding the use of the “cold chain” and, furthermore, without pathogenic microorganisms can develop inside it as they are absent. 25 Therefore, the term “stabilization” refers to the biochemical conditions of the egg white and its organoleptic components. A completely sterilized liquid egg white, i.e. free from pathogenic microorganisms or other heat-resistant microorganisms, maintained at room temperature it is able to remain stable at a microbial level and, therefore, not evolve into a harmful product and / or altered in its nutritional characteristics and / or 30 organoleptic. Even more advantageously, the above procedure allows to avoid the blowing of carbon dioxide before the packaging phase. The processes of egg white sterilization known to the state of the art, in fact, require the aforementioned carbon dioxide insufflation phase which, as a possible drawback, could present an alteration of the pH of the albumen and, therefore, a possible alteration of the functionality of the enzymes present in it and the colour of the product. 5 In general, the above procedure does not require the addition of any type of additive to the heat-treated product, i.e. egg white. The above mentioned advantages are mainly obtained thanks to the alternation between the phases of heat treatment and the physical-biochemical treatment phases (i.e. incubation and isothermal treatment). Heat treatments, in particular the second phases 10 heating, are made with a bacterial reduction technology that does not affects the main functional properties of the egg white, while the physical treatments biochemicals contribute to improving the microbial stability of the product. * * * * * Brief description of the drawings 15 Further features and advantages of the present invention will appear made clearer by the indicative, and therefore non-limiting, description of a form of preferred, but not exclusive, implementation of a stabilization process at room temperature of the liquid egg white, as illustrated in figure 1 which, according to a schematic view, illustrates a process for temperature stabilization 20 liquid egg white environment. With reference to the drawings, they serve only to illustrate ways of realising of the invention in order to better clarify, in combination with the description, the principles inventive principles underlying the invention. * * * * * 25 Detailed description of at least one embodiment The present invention is directed to a process for the stabilization of room temperature of the liquid egg white which, with reference to the figures, has been generically indicated with the number 100. Any changes or variations which, in light of the description, are evident to the 30 people with expertise in the sector must be considered to fall within the scope of protection established from the present invention, according to considerations of technical equivalence. Figure 1 shows a 100 procedure for stabilization at room temperature of the liquid egg white. In accordance with a preferred but not necessary aspect of the invention, the process 100 includes the preliminary stages of - prepare a pre-established quantity of eggs 101; 5 - shell the eggs and separate the egg white from the yolks 103 in order to obtain a quantity of egg white having a yolk contamination of less than 0.2% by weight. Preferably, the liquid raw egg white coming out of the sheller is filtered by be collected in a special storage tank. Even more preferably, procedure 100 provides for performing a cooling 10 preliminary 105 of the raw egg white at a temperature below 5 °C, preferably below 4°C, and maintained at this temperature homogeneously using a mechanical agitator placed in the same refrigerated storage tank. In accordance with the invention, the process 100 comprises the following operating steps: - preparation of a pre-established quantity of liquid egg white; 15 - execution of a first heat treatment 110; - incubation of heat-treated egg white 130; - execution of a second heat treatment 140; - performing an isothermal treatment of the egg white 160; - execution of a third heat treatment 170. 20 The execution phase of the first heat treatment 110 of the liquid egg white has the aim of eliminating some of the microorganisms naturally present in the egg white itself and, at the same time, activate the development of any spores present. In detail, the first heat treatment 110 comprises, in turn, a first heating phase at a temperature between 52 and 58 °C for a time interval of less than 300 25 seconds and, in addition, a second heating phase at a temperature between between 59 and 62 °C for a time interval of less than 40 seconds. The incubation phase 130 of the albumen, on the other hand, has the purpose of promoting germination of the spores. In detail, the incubation phase 130 involves conveying the albumen heat treated in a collection tank to store it at a temperature value 30 ideal for bacterial proliferation, preferably between 30 and 40 °C, and for a time interval between 16 and 26 hours. Advantageously, in this way, the germinated spores will be more sensitive and easily eliminated with subsequent heat treatments described in connection with this process 100. The execution phase of the second heat treatment 140 has the purpose of eliminating the bacteria present in the egg white, in particular bacteria deriving from spores germinated with the incubation phase 130. In detail, the second heat treatment 140 is similar 5 at the first heat treatment 110 and, therefore, includes a first stage heating to a temperature between 52 and 58 °C for a period of time less than 300 seconds and, in addition, a second warm-up phase at a temperature between 59 and 62 °C for a time interval of less than 40 seconds. The execution phase of an isothermal treatment 160 the albumen has the purpose of 10 eliminate the most resistant bacteria that had not been eliminated during the previous heat treatments 110, 140, especially in the second heat treatment 140. In detail, the isothermal treatment 160 of the egg white is performed at a temperature between 42°C and 52°C and, in addition, for a period of time of isothermal treatment between 7 hours and 17 hours. 15 The execution phase of the third heat treatment 170 of the egg white has the purpose of eliminate residual bacteria in the egg white that were not eliminated during the first and second heat treatment 110, 140. In detail, similarly to the first and second heat treatment 110, 140, the third heat treatment 170 comprises a phase of first heating to a temperature value between 50 and 55 °C for a 20 time interval less than 300 seconds and, in addition, running a second heating to a temperature value between 53 and 58 °C for a range of less than 40 seconds. In addition, the third heat treatment 170 is advantageously able to maintain the egg white at an optimal temperature for carry out a possible subsequent hot packaging phase (“hot filling”). 25 In this way, the stabilization procedure just described is advantageously able to allow the preparation of stable liquid egg white at room temperature, i.e. a liquid egg white having optimal microbiotic stability to the point that they do not necessarily need to be stored in refrigerators temperatures below 5°C. 30 In particular, the incubation phases 130 and the isothermal treatment phases 160 can be defined as physical-biochemical processes that have two main purposes to contribute with the ultimate goal of germinating and eliminating heat-resistant microorganisms from the egg white. The first purpose is to restart bacterial growth following a corresponding heat treatment. The second purpose, however, is to lower the protective functionality related to bacterial cell walls through the involvement of enhanced biochemical reactions associated with some bioactive proteins such as 5 lysozyme. Lysozyme, in fact, is an enzyme with bactericidal activity and naturally present in egg products. Advantageously, therefore, the particular combination of the operational phases of the procedure 100, in addition to actively eliminating part of the pathogenic microorganisms present in the egg white, allows to increase the bactericidal efficacy of lysozyme and other 10 similar enzymes present going to determine optimal operating conditions for such enzymes, such as, for example, the weakening of bacterial cell walls and / or increasing the mobility of enzymes in the egg white. In fact, the procedure 100 in accordance with the invention it is also able to liquefy the treated egg white so as to make it the distribution of lysozyme is more homogeneous and, therefore, it is 15 more free to act against any bacteria. In this way, furthermore, the 100 process does not require the injection of any gas such as the carbon dioxide inside the egg white, before its packaging, for ensure microbial stability. Carbon dioxide, in addition, would lead to the modification of the pH of the albumen and, therefore, a negative alteration of the enzymatic activity and 20 of the product color. In accordance with an aspect of the invention, each of the first heating steps It is performed with one or more heat exchangers, of the direct and / or indirect type. For example, heat exchangers can be plate (“PHE”) or tubular, single or multiple (“THE” or “m-THE”). 25 In other words, the first heating phases are based on the thermodynamic properties of fluids and their heat exchange capacity, in particular the exchange of energy thermal conduction and convection between the liquid albumen and the fluids present in the heat exchangers in direct or indirect contact with the conveying duct of the liquid egg white. 30 In accordance with another aspect of the invention, each of the second phases heating is performed with a direct electromagnetic heating device such as ohmic heating, radio frequency, microwaves, preferably a pulsed ohmic heating device. Advantageously, the use of a pulsed ohmic type heating device In this process, it allows the egg white to be heated up to 59° / 62° C. Preferably, each electromagnetic heating device is configured 5 to operate in a hyperbaric condition where the pressure to which the albumen is subjected is less than 45 bar. Even more preferably, the heat treatment performed by each device electromagnetic heating is achieved with the help of raising the temperature (due, precisely, to the aforementioned heating device 10 electromagnetic, preferably pulsed ohmic) and to a condition of overpressure at a value between 6 and 32 bar. In other words, the second warm-up phases are based on endurance capacity electric liquid egg white which, in detail, is heated by applying a electric field external to the conduit along which it is made to flow. The heating 15 direct electromagnetic, for example ohmic, is also defined as "volumetric heating" as it is able to act very quickly (i.e., with times less than a second) and homogeneously over the entire section of liquid albumen conveyed through the aforementioned external electric field. Advantageously, volumetric heating is able to perform a 20 bacterial reduction more effective than that achieved with the phases of first heating, that is with heat exchangers. Even more advantageously, volumetric heating is also able to not affect the main functional properties of egg white. In accordance with one aspect of the invention, the method 100 provides for conveying 25 the albumen with high pressure pumps to the portions of the treatment plant in where each phase of the first heat treatment takes place. Preferably, the above pumps are configured to operate at pressure values higher than a few units of bar up to values ​​equal to many tens of bar, but lower than 45 bars. 30 In accordance with one aspect of the invention, the aforementioned conveying step may be delegated to one or more positive displacement pumps present in the corresponding egg white processing plant in order to inject the product, i.e. the egg white, in the treatment circuit at a pressure of any value less than 45 bar. In accordance with another aspect of the invention, a positive displacement pump is preferably placed at least downstream of the incubation apparatus 5 of the albumen, for example a rising plate heat recovery apparatus, in so as to inject the albumen under pressure towards the apparatus configured to perform the second heat treatment. In accordance with one aspect of the invention, the method 100 comprises a first and a second cooling phase 120, 150 performed, respectively, before the 10 incubation phase 130 and isothermal treatment phase 160. In particular, each cooling stage 120, 150 is performed with heat exchangers. In this way, each cooling stage 120, 150 allows to cool the liquid egg white at a temperature value suitable for carrying out the corresponding and subsequent heat and biochemical treatment phase, i.e. the incubation phase 130 15 in one case and the isothermal treatment phase 160 in the other case. Preferably, following each second warm-up phase (“warm-up direct electromagnetic”), the liquid egg white is kept in a storage cell for a defined time, which is followed by a rapid cooling phase using a heat exchanger. Subsequently, the cooled liquid egg white is conveyed to 20 a section of the plant dedicated to heat regeneration and cooling via a plate heat exchanger. In accordance with a preferred aspect of the invention, the method also comprises a 180 hot filling phase performed after the third treatment 170°C to eliminate any residual bacteria resulting from the previous 25 heat treatment phases. In particular, the 180 hot filling phase includes to convey and package the egg white while maintaining it, in the meantime, at a temperature between 48 and 58 °C. Advantageously, thanks to the aforementioned temperatures of exercise, the hot filling phase 180 is also able to limit the possible recontamination of the albumen.

Claims

CLAIMS 1. Process for the sanitization and microbiological stabilization of liquid egg white stored at room temperature, comprising the operational phases of: - preparation of a predetermined quantity of egg white in a liquid state; 5 - execution of a first heat treatment on the egg white comprising the following phases: • execution of an initial heating at a temperature between 52°C and 58°C for a time interval of less than 300 seconds, • execution of a second heating at a temperature between 59°C and 62°C for a time interval of less than 40 seconds, in order to eliminate some of the microorganisms present in the egg white and activate any spores present; - incubation of the egg white at a temperature between 30°C and 40°C for a time interval of between 16 hours and 26 hours for the germination of any spores present;- carrying out a second heat treatment of the egg white equivalent to said first heat treatment to eliminate the bacteria present in the egg white deriving from the spores; - carrying out an isothermal treatment at a temperature between 42 2 0 °C and 52 °C for an isothermal treatment time interval between 7 hours and 17 hours to eliminate the bacteria present in the egg white not eliminated by said second heat treatment; - carrying out a third heat treatment of the egg white comprising the following phases: 25 • carrying out a first heating at a temperature value between 50 °C and 55 °C for a time interval of less than 300 seconds, • carrying out a second heating at a temperature value between 53 °C and 58 °C for a time interval of less than 40 seconds, so as to eliminate the bacteria present in the egg white not eliminated by said first and second heat treatment.; 2. Process according to claim 1, wherein each of said second heating steps is performed with a direct electromagnetic heating device.

3. A method according to claim 2, wherein each of said second heating steps is performed with a pulsed ohmic heating device. 5 4. A method according to claim 1 or 2, wherein each direct electromagnetic heating device is configured to operate in a hyperbaric condition where the pressure to which the egg white is subjected is less than 45 bar, preferably between 6 and 32 bar.

5. A process according to any preceding claim, comprising a hot-filling step performed in succession to said third heat treatment to eliminate any residual bacteria, wherein said hot-filling step involves maintaining the egg white at a temperature between 48°C and 58°C.

6. Process according to any preceding claim, wherein 15 each of said second heating steps is performed with one or more heat exchangers, of the direct and / or indirect type.

7. A process according to any preceding claim, wherein the egg white to be heat-treated during each first heat treatment step is conveyed by high-pressure pumps. 2 0 8. A process according to any preceding claim, comprising a first and second cooling step performed, respectively, before said incubation step and said isothermal treatment step, each cooling step being performed with heat exchangers. 2 5 9. A process according to any preceding claim, comprising the preliminary steps of - shelling a predetermined quantity of eggs; - separating the egg white from the yolks so as to obtain a quantity of egg white having a yolk contamination of less than 0.2% by weight. 30 10.Process according to claim 9, comprising a step of cooling said quantity of egg white to a temperature below 5 °C.