ROTATION SCHEME FOR BACTERIAL CULTURES IN FOOD PRODUCT FERMENTATION

Abstract

A method, system and computer program for selecting consecutive bacterial cultures for culturing a food product in a process for producing a fermented food product, the method comprising the steps of: culturing the food product with a first bacterial culture comprising at least one bacterial strain; isolating a sample during culturing with the first bacterial culture; determining at least one value indicative for a number of bacteriophages in the sample, e.g. using PCR, plaque assay, or pH; selecting a second bacterial culture for culturing the food product when the value is larger than a predetermined threshold, wherein the second bacterial culture comprises at least one bacterial strain, wherein the second bacterial culture differs from the first bacterial culture, wherein the sensitivities of the first and second bacterial culture for the bacteriophages in the sample are known and wherein the second bacterial culture is selected such as to reduce common bacteriophage sensitivities between the first and the second bacterial culture, and culturing the food product with the second bacterial culture.

Claims

1. A method for selecting consecutive bacterial cultures for culturing a food product in a process for producing a fermented food product, the method comprising: culturing the food product with a first bacterial culture comprising at least one bacterial strain; isolating a sample during culturing with the first bacterial culture; determining at least one value indicative for a number of bacteriophages in the sample; selecting a second bacterial culture for culturing the food product when the value is larger than a predetermined threshold, wherein the second bacterial culture comprises at least one bacterial strain, wherein the second bacterial culture differs from the first bacterial culture, wherein sensitivities of the first and second bacterial culture for the bacteriophages in the sample are known and wherein the second bacterial culture is selected optionally to reduce common bacteriophage sensitivities between the first and the second bacterial culture, and culturing the food product with the second bacterial culture.

2. The method according to claim 1, comprising determining the value indicative for the number of bacteriophages at a plurality of time points, optionally at least two time points, wherein the values at the plurality of time points are used to predict a predicted value at a predetermined critical time point, wherein the successively culturing the food product with the second bacterial culture is initiated when the predicted value is larger than the threshold at the critical time point.

3. The method according to claim 2, wherein the prediction is based on an artificial intelligence model.

4. 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 isolated sample.

5. The method according to claim 1, wherein the value indicative for the number of bacteriophages in the sample is determined by a DNA quantification method, optionally a DNA amplification method.

6. The method according to claim 5, wherein the value indicative for the number of bacteriophages in the sample is determined by quantitative polymerase chain reaction (qPCR).

7. The method according to claim 1, wherein the value indicative for the number of bacteriophages in the sample is determined by a phage plaque assay.

8. The method according to claim 1, wherein the value indicative for the number of bacteriophages in the sample is determined by pH measurements during culturing of the food product with the first bacterial culture.

9. The method according to claim 1, wherein the second bacterial culture is determined to be compatible with the first bacterial culture for subsequently culturing the food product when no common bacteriophage sensitivity exists between the at least one bacterial strain of the first bacterial culture and the at least one bacterial strain of the second bacterial culture.

10. The method according to claim 1, wherein the sensitivity to bacteriophages for the first and second bacterial cultures is determined by accessing a database.

11. The method according to claim 1, further including accessing a compatibility matrix for a plurality of bacterial strains, wherein the compatibility matrix indicates compatibility between at least said first and second bacterial cultures, wherein the compatibility is based on bacteriophage sensitivity of the at least one bacterial strain in the first and second bacterial cultures.

12. The method according to claim 8, wherein culturing the food product with the second bacterial culture is initiated when a predetermined threshold pH value during culturing of the food product with the first bacterial culture is not reached within a predetermined period of time after starting culturing the food product with the first bacterial culture.

13. The method according to claim 1, wherein bacterial cultures are identified by means of a readable code provided in and/or on a packaging of said bacterial cultures.

14. The method according to claim 1, wherein the first bacterial culture comprises at least a first bacterial strain and the second bacterial culture comprises at least a second bacterial strain, wherein the first bacterial strain has different bacteriophage sensitivities compared to the second bacterial strain.

15. The method according to claim 1, further comprising: isolating a second sample during culturing of the food product with the second bacterial culture, determining at least one value indicative for a number of bacteriophages in the second sample; selecting a third bacterial culture for culturing the food product when the value is larger than a predetermined threshold, wherein the third bacterial culture comprises at least one bacterial strain, wherein the third bacterial culture differs from the first and from the second bacterial culture, wherein the sensitivities of the first, second and third bacterial cultures for the bacteriophages in the second sample are known and wherein the third bacterial culture is selected optionally to reduce common bacteriophage sensitivities between the first and second bacterial culture, and said third bacterial culture, and culturing the food product with the third bacterial culture.

16. A system for selecting consecutive bacterial strains for culturing a food product in a process for producing a fermented food product, the system comprising: a controller; means for culturing the food product, and an analysis unit for monitoring a value indicative for the number of bacteriophages in a sample of the process for producing a fermented food product; and wherein the controller is configured to operate the system to perform: culturing the food product with a first bacterial culture comprising at least one bacterial strain; determining, by means of the analysis unit, a value indicative for the number of bacteriophages in the sample of the process for producing a fermented food product; selecting a second bacterial culture for culturing the food product when the value is larger than a predetermined threshold, the second bacterial culture comprising at least one bacterial strain and differing from the first bacterial culture, sensitivities of the first and second bacterial culture for the bacteriophages in the sample are known and wherein the second bacterial culture is selected optionally to reduce common bacteriophage sensitivities between the first and the second bacterial culture; and subsequently culturing the food product with the second bacterial culture.

17. A computer program product configured to 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: receive a value indicative for the number of bacteriophages in a sample of the process for producing a fermented food product during culturing the food product with a first bacterial culture including at least one bacterial strain; select a second bacterial culture for subsequently culturing the food product, when the value is larger than a predetermined threshold, the second bacterial culture comprising at least one bacterial strain and differing from the first bacterial culture, sensitivities of the first and second bacterial culture for the bacteriophages in the sample are known and wherein the second bacterial culture is selected optionally to reduce common bacteriophage sensitivities between the first and the second bacterial culture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] 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.

[0083] In the drawings:

[0084] FIG. 1 shows a schematic diagram of an embodiment of a method for selecting consecutive bacterial cultures for culturing a food product;

[0085] FIG. 2A shows a schematic diagram of acidification and the influence of a phage infection;

[0086] FIG. 2B shows a schematic diagram of an embodiment of a method for rotating bacterial cultures in function of phage concentration;

[0087] FIG. 3 shows a schematic diagram of an embodiment of a compatibility matrix of bacterial cultures regarding bacteriophage sensitivity; and

[0088] FIG. 4 shows a schematic diagram of a method of the invention;

DETAILED DESCRIPTION OF THE INVENTION

[0089] FIG. 1 shows a schematic diagram of an embodiment of a method for selecting consecutive bacterial cultures for culturing a food product. In a first step, the food F is cultured with a first bacterial culture C1 comprising at least one bacterial strain. In a second step, a sample S is isolated from the first bacterial culture during culturing. In a third step, at least one value V indicative for a number of bacteriophages in the sample S is determined. When the value is larger than a predetermined threshold T, the next batch of the food F is cultured with a second bacterial culture C2. The second bacterial culture comprises at least one bacterial strain, differs from the first bacterial culture C1 and the sensitivities of the first bacterial culture (C1) and second bacterial culture (C2) for the bacteriophages in the sample S are known and wherein the second bacterial culture C2 is selected such as to reduce common bacteriophage sensitivities between the first bacterial culture C1 and the second bacterial culture C2.

[0090] Optionally, when the value V is not larger than the predetermined threshold T, culturing is continued with the first bacterial culture C1, until a value V is determined that is larger than threshold T.

[0091] The sample S is a process sample, that is taken from anything that came into contact with said bacterial culture, e.g. rinsing water, whey, fermented food product, curd, etc.

[0092] Preferably, the invention comprises at least two values V, more preferably three values V, each taken at a different time point after the starting of the culturing.

[0093] 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.

[0094] 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, 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 basal 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 C.sub.c, wherein the acidification with bacterial culture B will no longer be able to reach the desired pH. 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.

[0095] 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.

[0096] 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, A and C are compatible and can thus be successive in an adapted order. A and B are incompatible, and it should thus be avoided to use said bacterial cultures successively. It should be understood that while FIG. 3 shows 4 bacterial cultures, the compatibility matrix can comprise any number of cultures. Additionally, it is not a requirement that the matrix is completely filled as data may be missing. Preferably, the compatibility matrix is filled out completely.

[0097] FIG. 4 shows a schematic diagram of a method 100 for selecting consecutive bacterial cultures for culturing a food product 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, the food product is cultured with a first bacterial culture comprising at least one bacterial strain. In a second step 102, a sample is isolated during culturing with the first bacterial culture. In a third step 103, at least one value is determined indicative for a number of bacteriophages in the sample. In a fourth step 104, a second bacterial culture is selected for culturing the food product when the value is larger than a predetermined threshold, wherein the second bacterial culture comprises at least one bacterial strain, wherein the second bacterial culture differs from the first bacterial culture, wherein the sensitivities of the first and second bacterial culture for the bacteriophages in the sample are known and wherein the second bacterial culture is selected such as to reduce common bacteriophage sensitivities between the first and the second bacterial culture. In a fifth step 105, the food product is cultured with the second bacterial culture.

[0098] 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.

[0099] 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,

[0100] 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.

[0101] 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.

[0102] 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.