In general such methods are very well known in this field of technology. In particular industrialized ways of processing large volumes in an hygienic way, resulting in well preserved quantities of such liquid, are applied on large scale.

More in particular it is considered of utmost interest to provide egg liquid products which are substantially free from bacterial human pathogens, more specifically free from Salmonella Enteriditis (hereinafter SE). However in this field of applied food technology more pathogens are known and can be remedied in substantially the same way. As to reduction pathogen concentrations as usual in this field of technology reduction is calculation in mathematical power of 10 multiplication factors. More in detail, reduction is expressed as reduced by 10 having power 1, by 100 having power 2, and so on, whereas in most cases this reduction is typified as respectively lloglO, 21ogl0, and so on,

Since very long time such liquids are treated by well known pasteurization or

sterilization. These treatments are thermal treatments and, although reliable when applied in a proper way, are considered disadvantageous as to several aspects.

First, applying the correct thermal and thermodynamic conditions does ask for advanced control which has to be applied very accurately. If not, protein matter features will be modified which will influence economic value of such liquid substantially.

Second, said thermal treatment today is considered to cost too much energy, and moreover is a source of thermal contamination. Since about 10 years a lot of effort has been done to search for more suitable pasteurization methods. Although other approaches are generally known from scientific literature and from patent documents, neither technology is shown providing sufficient pathogen reduction, nor egg liquid products are resulting having preserved the right matter features because of for example denaturation effects.

From Bari et al., 'Effect of Hydrostatic Pressure Pulsing on the Inactivation of

Salmonella Enteriditis in Liquid Whole Egg' , FOODBORNE PATHOGENS AND

DISEASE, volume 5, Number 2, 2008, it is know to tackle salmonella contamination in Liquid Whole Egg (hereinafter LWH) by applying a certain pressure regime. In this document many details as to pH, starting temperature and pressurizing periods are outlined.

However, as to the experience of applicant the characteristics as shown thus far are not sufficient to manufacture suitable egg liquid product on large scale basis.

The present invention aims to remove or reduce the above-mentioned problems.

Particularly, the invention aims to provide a method that can lead to optimum pathogen reduction in an efficient manner.,

According to an aspect of the invention, to this aim, there is provided a method for pasteurizing egg liquid, the method at least comprising

- in a pasteurization processing step applying a pressure regime having at least one maximum value at at least two (different, i.e. separate) time periods.

It has appeared that excellent liquids result, both as to pathogenic characteristics, and as to shelf life. The egg liquid so obtained has appeared to have excellent characteristics as to pathogen treatment, both immediately after treatment and even after some months. This means that an advantageous economic operation, i.e. highly reduced heating costs and pollution, is resulting.

Also, it has been found that negative denaturation effects can be reduced or avoided. Preferably to that aim, a relatively low maximum pressure in the process can be applied, for example a maximum pressure pmax < 400 MPa. Also, relatively short processing times can be applied (e.g. total processing times being in the range of only 1-20 minutes, particularly 1-10 minutes, still providing good results regarding pathogenic

characteristics and shelf life.

In a preferred embodiment, good results can be achieved in case the pressure regime includes a sequence of compressions (e.g. to a maximum pressure p _max) and

decompressions (e.g. to pressures lower than p _max) , with intermediate pressure levels (i.e. between each compression and subsequent decompression) different from zero, the intermediate pressure levels particularly being higher than atmospheric pressure. In a further embodiment, a starting pressure of the sequence can be an environment pressure or atmospheric pressure, and particularly a pressure that is lower than a said intermediate pressure. In a preferred embodiment, the pressure can be reduced to normal (environment) or atmospheric pressure after application of or as a final step of the pressure regime (e.g. after a said sequence of compressions and decompressions). For example, a final decompression of the sequence can be a decompression to normal (environment) or atmospheric pressure, as will be appreciated by the skilled person.

According to a further embodiment, the pressure regime is applied adiabatically, that is, the pasteurization processing step of applying the pressure regime having the at least one maximum value at at least two time periods, is preferably carried out under adiabatic conditions. Preferably, during the adiabatic processing of the liquid a temperature T of the liquid remains within a preferred temperature range of 0 < T < 50, with T in °C. Extra advantageous embodiments of the method of the invention are characterized by one or more of the following features:

-a pressure regime having a pulse form, the pulse form for example comprising a relatively short sequence of n pulses with n a natural number and 1 < n < 5;

-said pulse form, having intermediate pressure pmin values a range 0 < pbase < 150, and having maximum pressure values pmax in a range 75 < pmax < 400, with p in MPa;

-said pulse form, having preferred ranges 100 < pmin < 130 and 200 < pmax < 375, with p in MPa;

-said form has compression rates in a range 5 < Ap/At < 100,

with Ap/At in MPa/s;

-said form has decompression rates in a range 2 < Ap/At < 400,

with Ap/At in MPa/s;

-said form has compression times tC in seconds with 4 < tC < 80;

-said form has decompression times tD in seconds with 1 < tD < 200;

-said form has residence times tMA in minutes at maximum pressure with

1 < tMA < 10;

-said form has residence times tMI in minutes at intermediate pressure with

0 < tMI < 1;

-said pulse form being a trapezoidal pulse form;

-said egg liquid volume has a temperature T with 0 < T < 50, with T in °C;

-said first preparation step further comprising applying a pH acid concentration regime, with 5 < pH < 9; and

-said pasteurization processing step comprising pulse time periods Atpulse,

with 1 < Atpulse < 10 minutes, with a preferred range 1< Atpulse < 5 minutes.

Said pulse form can be a trapezoidal pulse form or a different pulse form, for example a pule form having non-linear compression rates and decompression rates. Preferably, the pulse form includes a constant maximum pressure section, for example an upper leg of the pulse form wherein the pressure is held at a (constant) maximum pressure p _max during a certain respective residence time tMA. Also, preferably, the pulse form includes constant intermediate pressure sections

(wherein the pressure is held at a constant intermediate pressure pmi _n during a certain respective residence time tMI).

A said trapezoidal pulse form can for example be defined as a pulse that follows -in sequence and starting from an initial pressure (pmin) - a linearly rising flank, an upper (maximum pressure) leg and a linearly falling flank of a trapezoid (see Fig. 1).

For example, a said rising flank of said pulse, i.e. a first part of the pulse, is a

compression step of the process, e.g. a compression step wherein the product (particularly egg liquid) is being compressed at a certain compression rate Δρ/At (MPa/s), e.g. during a compression time tC.

For example, a falling flank of said pulse, i.e. a third part of that pulse, is a

decompression step of the process, e.g. a decompression step wherein the product (particularly egg liquid) is being decompressed at a decompression rate Δρ/At (MPa/s), e.g. during a decompression time tD.

Also, for example, a starting point for said or each pulse (e.g. being a lower leg of the respective pule form, the lower leg preferably being in parallel with a said upper leg) can be a minimum (e.g. initial, e.g. atmospheric, pressure) or intermediate pressure value pmi _n .

Furthermore the present invention provides an egg liquid processed in accordance with the method of one of the above characteristics. With great advantage such liquids can be sold safely, not only immediately after processing but also after some months. This implies a further advantage as to logistics concerning transport and storage of such liquids.

According to a further advantageous embodiment, the egg liquid of the present invention is characterized in that said liquid comprises whole liquid egg.

In order to explain a non-limiting embodiment of the method of the present invention in more detail reference is made to drawing, wherein the only FIGURE 1 schematically shows a graph giving the parameters handled and set.

More in particular in FIGURE 1 a graph is shown, having 2 coordinate axes, a vertical one for pressure values p, and a horizontal one for time values t.

As can be seen values are only shown schematically, whereas further details are given in the EXAMPLES 1 and 2 hereinafter.

Figure 1 schematically depicts part of a method for processing egg liquid, the method comprising:

- a pasteurization processing step applying a pressure regime (to the product, held in the container), the pressure regime having at least one maximum value (p _m ax) at at least two (separate) time periods. The method may also include e.g.: (before applying the pressure regime) a preparation step preparing at atmospheric pressure a well determined volume of egg liquid (at a certain starting temperature). The method may also include, after said first preparation step: transferring said volume of egg liquid into a pressurizing container (not shown). Besides, the method may include (after the pressure regime has been applied): supplying the processed liquid into storage conditions. To the skilled person it will be clear that these preparation steps and finalization step can be carried out in various ways.

Figure 1 shows an non-limiting example, including application of a pressure sequence trapezoid pulse forms. Particularly, as follows from Fig. 1, in a preferred embodiment the pressure regime includes at least two separate pressurizing steps wherein the pressure is held at least one maximum value p _max ( at respective time periods tMA), wherein more particularly the pressure regime includes an intermediate step between each said two separate pressurizing steps wherein the pressure is lower that said maximum value p _max .

In a the present embodiment, the pressure regime has a substantially trapezoidal pulse form. In an extra advantageous embodiment, the pulse form comprises a sequence of n pulses with n a natural number and 1 < n < 5.

As can be seen the method of pressurizing in the present set-up means gives for example a sequence of compressions and decompressions, with the possibility of intermediate pressure levels different from environment or atmospheric pressure.

Thus in the present graph (Fig. 1) different pressure p values can be distinguished, i.e.

- a starting pressure po (the intersection of the p-axis and t-axis), particularly an environment pressure, e.g. starting at po = 1 atmosphere,

- a pmin giving an intermediate pressure,

- a max giving a upper maximum for the pressure,

whereas the subsequent compressions and decompressions are characterized by their compression rates and decompression rates respectively.

Consequently a sequence of several adjacent compressions and decompressions, or simply ups and downs, can be typified as pressure pulses or pulsed pressurizing.

As regards the horizontal axis various kind of points in time, time periods, and time intervals, for the process are shown, i.e.

- a cycle time tCY, e.g. being a total time period in which the pressure regime is being applied;

- a first compression time tC when starting from po, i.e. the time period during which the first compression is carried out;

- a final decompression time tD back from maximum to po, i.e. the time period during which the final decompression is carried out;

- an interval compression time starting from intermediate pressure, tCI, i.e. the time period tCI during which the interval compression is being carried out; - an interval decompression time ending at intermediate pressure, tDI, i.e. the time period tDI during which the interval decompression is being carried out;

- a residence time at pmax, tMA, i.e. the time period tMA during which the pressure is being held at the maximum pressure p _max of each pressure pulse; and

- a residence time at an intermediate level pmin, tMI, which is the time period during which the pressure is held at the reduced pressure level p _m j _n the intermediate

decompression and the intermediate compression steps.

More in particular in this FIGURE 1 two pulses, thus n = 2, are presented. It has been found that good pasteurizing results can be achieved in this manner.

EXAMPLE 1

As an example of the experiments done the following recipe was followed.

Fresh eggs were purchased in a consumer shop for dairy products.

Said eggs were manually cleaned with clear water with chlorine bleach (200 ppm) and subsequently rinsed with sterile water.

Thereafter under sterile hood said eggs were broken and the resulting liquid homogenized to so-called LWE (Liquid Whole Egg).

In order to investigate HPP efficacy three different samples SI, S2, S3, were prepared separately and HPP - processed identically, wherein,

51 was said raw product,

52 was said raw product, SE inoculated at a level of 10exp6 CFU/mL, and

53 was said raw product, SE inoculated at a level of 10exp9 CFU/mL.

For the definition of the commonly known CFU/mL', see e.g. http://en.wilripedia.org. which teaches that in microbiology, colony- forming unit (CFU) is a rough estimate of the number of viable bacteria or fungal cells in a sample. Viable is defined as the ability to multiply via binary fission under the controlled conditions. In contrast in a microscopic evaluation, all cells, dead and living are counted. The visual appearance of a colony in a cell culture requires significant growth - when counting colonies it is uncertain if the colony arose from one cell or 1,000 cells. Therefore results are reported as CFU/mL (colony-forming units per milliliter) for liquids. In the present experiment, high pressure processing (HPP) tests were carried out at,

- pressure rates Δρ/At (MPa/s) of 6.7;

- starting temperature of 4 degrees Celsius;

- applied processing mode: 3 times processing for 3 minutes (i.e. n=3);

- highest pressure (p _max ) = 350 Mpa.

For the initial and final counts Ni and Nf the following data resulted, whereas ED gives the 'efficacite destructrice' with ED = log Ni - logNf , sometimes called IE as inactivation efficienc .

For counting non-selective agar was applied.

From the above it will be clear to those skilled in the art that applying such HPP conditions gives very advantageous results to be used for customary applications.

EXAMPLE 2

For further LWE samples, without and with 10exp9 SE inoculation, processed in the same way the following coupled data were found.

From the above it might be clear to those skilled in the art that both immediate advantages as shown before are resulting and very suitable shelf life data result.

All the experiments were carried out in a high pressure vessel as referred to in Buzrul et al., Compression heating of selected pressure transmitting fluids and liquid foods during high pressure treatment, Journal of Food Engineering, 85 (2008), 466 - 472.

It might be clear that those skilled in the art that the invention is not limited to the embodiments described here-above. It will be clear that he invention can be modified in various ways, within the scope of the attached claims.

For example processing such liquids may imply one or more of:

- processing only albumen,

- processing only yolk,

- processing preferred combinations of the above, and

- processing preferred combinations of the above under suitable pH conditions.

Furthermore it has appeared that such pathogen treatment is very advantageous such that suchlike liquid foods can be handled in all desired and preferred volumes and

combinations, also after having been packaged.

Also, e.g., the temperature of the product may change during the process. Particularly, the process can be an adiabatic process (leading e.g. to a rise of temperature of the liquid during compression as will be clear to the skilled person).

Also, in the examples above, pulse forms having linear compression and linear decompression rates have been applied. Alternatively, a non-linear compression rate (Δρ/Δί) can be applied in one or more of the pulse forms. Also, alternatively, a non-linear decompression rate (Δρ/At) can be applied in one or more of the pulse forms.