A METHOD FOR DETERMINING AN ORDER IN WHICH A FOOD PRODUCT IS CULTURED

Abstract

A method, process, and computer program for determining an order in which a food product is successively cultured with a set of bacterial cultures in a process for producing a fermented food product, each bacterial culture of the set of bacterial cultures including at least one bacterial strain, wherein the set of bacterial cultures comprises a first subset of one or more bacterial cultures comprising one or more unknown bacterial strain, and a second subset of one or more bacterial cultures comprising one or more known bacterial strains, wherein each of the bacterial strains of the second subset is known; wherein the process is carried out with an initial order of the set of bacterial cultures; wherein during culturing with each bacterial culture of the first subset a process sample is collected, wherein a culture sample of a bacterial culture of the second subset is exposed to the collected process samples in order to determine bacteriophage sensitivities of the one or more bacterial cultures of the second subset to bacteriophages present in the collected process sample, wherein an adapted order of the set of bacterial cultures is determined based on the determined bacteriophage sensitivities such as to reduce common bacteriophage sensitivities in successive bacterial cultures.

Claims

1. A method for determining an order in which a food product is successively cultured with a set of bacterial cultures in a process for producing a fermented food product, wherein the set of bacterial cultures comprises a first subset of one or more bacterial cultures comprising one or more unknown bacterial strain, and a second subset of one or more bacterial cultures comprising one or more known bacterial strains, wherein each of the bacterial strains of the second subset is known; wherein the process is carried out with an initial order of the set of bacterial cultures; wherein during culturing with each bacterial culture of the first subset a process sample is collected, wherein a culture sample of a bacterial culture of the second subset is exposed to the collected process samples in order to determine bacteriophage sensitivities of the one or more bacterial cultures of the second subset to bacteriophages present in the collected process sample, wherein an adapted order of the set of bacterial cultures is determined based on the determined bacteriophage sensitivities of each of the cultures, optionally to reduce common bacteriophage sensitivities in successive bacterial cultures.

2. The method according to claim 1, wherein in a subsequent process the food product is successively cultured with the set of bacterial cultures in the adapted order.

3. The method according to claim 1, wherein the adapted order is employed dynamically during the process for producing the fermented food product.

4. The method according to claim 1, wherein each bacterial strain of the one or more bacterial cultures of the second subset is exposed to the collected process sample for determining the bacteriophage sensitivities.

5. The method according to claim 1, wherein one or more bacterial strains of the one or more bacterial cultures of the second subset are individually exposed to each of the collected process samples.

6. The method according to claim 1, wherein combined bacterial strains of the one or more bacterial cultures of the second subset are exposed to each of the collected process samples.

7. The method according to claim 1, wherein the adapted order of the set of bacterial cultures is selected optionally to minimize common sensitivities to bacteriophages in successive bacterial cultures.

8. The method according to claim 1, wherein determining bacteriophage sensitivities is performed by determining a value indicative for a number of bacteriophages in the collected process sample.

9. The method according to claim 8, wherein the value indicative for the number of bacteriophages is determined by performing one or more quantitative polymerase chain reaction (qPCR) measurements.

10. The method according to claim 1, wherein the fermented food product is a dairy product, optionally a cheese or a yoghurt.

11. The method according to claim 1, wherein determining the value indicative for the number of bacteriophages is performed by detecting and/or identifying bacteriophages in the sample of the process for producing a fermented food product.

12. The method according to claim 1, wherein information regarding bacteriophage sensitivities is stored in a database, wherein the database is used for determining culturing order in a different process for producing fermented food product.

13. The method according to claim 1, wherein the set of bacterial cultures includes two to twenty bacterial cultures, optionally three to ten bacterial cultures, optionally three to six bacterial cultures.

14. The method according to claim 1, wherein the one or more bacterial cultures of the first subset are provided by one or more first providers, and wherein the one or more bacterial cultures of the second subset are provided by one or more second providers, wherein the one or more first and second providers are different.

15. A process for producing a fermented food product by successively culturing a food product with a set of bacterial cultures, wherein an order of bacterial cultures in which the food product is successively cultured is determined by performing the method according to claim 1.

16. A computer program product configured to be run on a machine for selecting consecutive bacterial cultures for culturing a food product in a process for producing a fermented food product, the computer program product being configured to perform the method according to claim 1 for determining an order in which the food product is successively cultured with a set of bacterial cultures.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary embodiments are given by way of non-limitative illustration. It is noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting example.

[0073] In the drawings:

[0074] FIG. 1 shows a schematic diagram of an embodiment of a method for determining an order in which a food product is successively cultured during fermentation;

[0075] FIG. 2A shows a schematic diagram of acidification and the influence of a phage infection;

[0076] FIG. 2B shows a schematic diagram of an embodiment of a method for rotating bacterial cultures in function of phage concentration;

[0077] FIG. 3 shows a schematic diagram of an embodiment of a compatibility matrix of bacterial cultures regarding bacteriophage sensitivity; and

[0078] FIG. 4 shows a schematic diagram of a method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0079] FIG. 1 shows a schematic diagram of an embodiment of a method for determining an order in which a food product is successively cultured during fermentation. The starting point can be found in the top part of the figure, showing a set of bacterial cultures in a process for producing a fermented food product, which are divided in two subsets, a first subset of one or more bacterial cultures (U.sub.1-U.sub.N) comprising one or more unknown bacterial strains, and a second subset of one or more bacterial cultures (K.sub.1-K.sub.N) comprising one or more known bacterial strains, wherein each of the bacterial strains of the second subset is known. Both subsets are herein shown as containing five bacterial cultures, but both subsets can contain any amount of bacterial cultures, with a minimum of one. Preferably, the total number of bacterial cultures in the set includes two to twenty bacterial cultures, more preferably three to ten bacterial cultures, even more preferably three to six. Each bacterial culture comprises one or more bacterial strains. Preferably, the bacterial cultures do not significantly differ in performance between each other, in order to obtain a continuous quality between batches of fermented food products.

[0080] An initial order of bacterial cultures is chosen for rotating during food product fermentation. This can be carried out based on the knowledge of the sensitivity to bacteriophages of the known bacterial strains, and potentially by the incomplete data available for unknown bacterial strains. Alternatively, the initial order of bacterial cultures is randomly distributed. FIG. 1 shows a first bacterial culture with at least one unknown bacterial strain first, subsequently followed by a bacterial culture with known bacterial strains, but this is in no way a requirement.

[0081] The food product is then fermented in the presence of the first bacterial culture. Batches may be changed every time a certain pH is reached or a certain time has passed. Multiple subsequent batches can be produced with one bacterial culture before switching to a next bacterial culture. Following fermentation in the presence of the first bacterial culture, the food product is fermented with the subsequently chosen bacterial culture. This process is repeated until each of the bacterial cultures has been used. During or after fermentation with each bacterial culture comprising at least one unknown bacterial strain, a process sample is taken from anything that came into contact with said unknown bacterial culture, e.g. rinsing water, whey, fermented food product, curd, etc.

[0082] In a next step, said process samples are each brought into contact with culture samples of the known bacterial cultures and/or cultures of the known bacterial strains and bacteriophages are detected or quantified in the known bacterial cultures and/or cultures of the known bacterial strains. Preferably, the process samples are each brought into contact with each of the bacterial cultures and/or cultures of the known bacterial strains. A compatibility matrix between known and unknown strains can be filled out, as indicated in the third step of FIG. 1.

[0083] Based on the compatibility matrix, an adapted order of bacterial cultures can be determined, wherein incompatible cultures used successively are minimized, preferably are incompatible cultures not placed subsequently at any point in the rotation. The term “incompatible cultures”, as used herein, may refer to bacterial cultures which at least one same bacteriophage can infect, and thus impede growth of said bacterial cultures and therefore harm acidification performance.

[0084] FIG. 2A shows a schematic diagram of acidification and the influence of a phage infection. In a graphical view of the pH in function of the time, an ideal situation would be outcome A. Threshold H is the ideal pH after acidification, which has been reached in situation A, wherein no influence of bacteriophages is detected. In case of a moderate phage infection, the acidification, thus lowering of the pH, will be slowed down and a longer time is necessary to reach threshold pH. This is depicted by outcome B. Lastly, in case of a severe phage infection, outcome C is reached. The acidification is compromised to such a degree, that reaching the threshold pH is unlikely or will take a long time. This diagram signifies the importance of good bacteriophage control and a phage-robust rotation scheme.

[0085] FIG. 2B shows a schematic diagram of an embodiment of a method for rotating bacterial cultures in function of phage concentration. When bacterial culture A is used, the concentration of bacteriophages against bacterial culture A will increase, either linear, as depicted in FIG. 2B, or non-linear, as function of time and as function of the number of subsequent batches of food product that are produced with bacterial culture A. After a specific time, or a specific pH threshold is reached, bacterial culture A will be replaced by bacterial culture B, as depicted by the vertical dotted line. If bacterial culture B is compatible with bacterial culture A, thus no common bacteriophage sensitivities are present, the bacteriophage concentration is reduced to a low level, at which point different bacteriophages can start growing, which can infect bacterial strains from bacterial culture B. In the case where bacterial culture is incompatible with bacterial culture A, thus common bacteriophage sensitivities exist, the leftmost diagonal dotted line may appear. In this case, the same bacteriophages will be able to multiply further and will reach a critical concentration Cc, wherein the acidification with bacterial culture B will no longer be able to reach the desired pH within the target time. The phage concentration growth is here depicted as linear, but may also be non-linear. In the case wherein bacterial culture A and B are compatible, the process can be continued and repeated with bacterial culture C, etc.

[0086] Bacteriophages are present everywhere, including bulk starter cultures. Generally, bacterial cultures will be rotated during the process, in the hope that the strains in the cultures are different so no common bacteriophage sensitivities are present.

[0087] FIG. 3 shows a schematic diagram of an embodiment of a compatibility matrix of bacterial cultures regarding bacteriophage sensitivity. A “V” signifies bacteriophage compatibility, thus no common bacteriophage sensitivities, an “X” signifies bacteriophage incompatibility, thus having common bacteriophage sensitivities. In this example, K.sub.1 and U.sub.1 are compatible and can thus be successive in an adapted order. K.sub.1 and U.sub.2 are incompatible, and it should thus be avoided to put said bacterial cultures successively in an adapter order of a bacteriophage rotation.

[0088] In an example, a supplier of bacterial cultures will provide the user with the correct order of his provided bacterial cultures, as this provider would have tested each culture against known bacteriophages and each other. However, whenever a food producer wants to mix bacterial cultures in his rotation of more than one supplier, he does not know the correct rotation order of each of the bacterial cultures, as suppliers usually do not disclose bacteriophage information. If bacterial cultures of different suppliers are used, the user has no way to optimize the order but trial and error, or characterizing each bacterial culture. However, with the above mentioned method, this is no longer necessary. By running the rotation of bacterial cultures just once, analysis can be performed by one of the suppliers on a sample resulting from the bacterial cultures that comprise unknown strains.

[0089] FIG. 4 shows a schematic diagram of a method 100 for determining an order in which a food product is successively cultured with a set of bacterial cultures in a process for producing a fermented food product. In some examples, part of the method is a computer implemented method configured to be run on a machine. In a first step 101, a first subset is defined of one or more bacterial cultures comprising one or more unknown bacterial strain. In a second step 102, a second subset is defined of one or more bacterial cultures comprising one or more known bacterial strains, wherein each of the bacterial strains of the second subset is known. In a third step 103, the process is carried out with an initial order of the set of bacterial cultures. In a fourth step 104, during culturing with each bacterial culture of the first subset, a process sample is collected. In a fifth step 105, a culture sample of a bacterial culture of the second subset is exposed to the collected process samples in order to determine bacteriophage sensitivities of the one or more bacterial cultures of the second subset to bacteriophages present in the collected process sample. In a sixth step 106, an adapted order of the set of bacterial cultures is determined based on the determined bacteriophage sensitivities such as to reduce common bacteriophage sensitivities in successive bacterial cultures.

[0090] It will be appreciated that the method may include computer implemented steps. All above mentioned steps can be computer implemented steps. Embodiments may comprise computer apparatus, wherein processes performed in computer apparatus. The invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source or object code or in any other form suitable for use in the implementation of the processes according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a ROM, for example a semiconductor ROM or hard disk. Further, the carrier may be a transmissible carrier such as an electrical or optical signal which may be conveyed via electrical or optical cable or by radio or other means, e.g. via the internet or cloud.

[0091] Some embodiments may be implemented, for example, using a machine or tangible computer-readable medium or article which may store an instruction or a set of instructions that, if executed by a machine, may cause the machine to perform a method and/or operations in accordance with the embodiments.

[0092] Various embodiments may be implemented using hardware elements, software elements, or a combination of both. Examples of hardware elements may include processors, microprocessors, circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, microchips, chip sets, et cetera. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, mobile apps, middleware, firmware, software modules, routines, subroutines, functions, computer implemented methods, procedures, software interfaces, application program interfaces (API), methods, instruction sets, computing code, computer code, et cetera.

[0093] Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications, variations, alternatives and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged and understood to fall within the framework of the invention as outlined by the claims. The specifications, figures and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense. The invention is intended to embrace all alternatives, modifications and variations which fall within the spirit and scope of the appended claims. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

[0094] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.