NEW FOOD PRODUCTS STABLE AT AMBIENT TEMPERATURE
The application is directed to a process for manufacturing a food product stable at ambient temperature based on the inoculation of a food product with stable lactic acid bacteria able to maintain viability and to slightly decrease pH when stored at ambient temperature. The invention is also directed to the use of these stable lactic acid bacteria for inoculation in a food product.
1 . A process for manufacturing a food product stable at ambient temperature, said process comprising:
1) providing an initial food product with a pH of between 3.4 and 4,6, in particular an initial low bacteria-containing food product with a pH of between 3.4 and 4.6 containing a level of bacteria which is no more than 1×10 2 CFU per g;
2) adding to the initial food product, in particular to the initial low bacteria-containing food product, one or more stable lactic acid bacteria in a total amount of at least 1×10 5 CFU per g, to obtain a food product stable at ambient temperature,
characterized in that:
(i) each of said one or more stable lactic acid bacterium is selected from the group consisting of strains of species Lactobacillus plantarum, Lactobacillus zymae, Lactobacillus rossiae, Lactobacillus collinoides, Lactobacillus similis, Lactobacillus versmoldensis, Lactobacillus acidipiscis, Lactobacillus hammesii, Lactobacillus namurensis, Lactobacillus nodensis and Lactobacillus tucceti; and
(ii) each of said one or more stable lactic acid bacterium, when added in an amount of 1×10 7 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds:
a) retains viability in an amount of at least 5×10 3 CFU/g after storing said test yoghurt 30 days at a temperature of 37° C.; and
b) decreases the pH of said test yoghurt of at most 0.6 units after storing said test yoghurt 30 days at a temperature of 37° C.,
2 . The process according to claim 1 , wherein said stable lactic acid bacterium when added in an amount of 1×10 7 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds, retains viability in an amount of at least 1×10 4 CFU/g, at least 5×10 4 CFU/g at least 1×10 5 CFU/g, at least 5×10 5 CFU/g or at least 1×1 CFU/g, after storing said test yoghurt 30 days at a temperature of 37° C.
3 . The process according to claim 1 or 2 , wherein said stable lactic acid bacterium, when added in an amount of 1×10 7 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds decreases the pH of said test yoghurt of at most 0,5 units, at most 0.4 units or at most 0.3 units, after storing said test yoghurt 30 days at a temperature of 37° C.
4 . The process according to any one of claims 1 to 3 , wherein said initial food product with a pH of between 3.4 and 4.6 is selected from the group consisting of a milk-based product such as a fermented dairy product or a chemically-acidified dairy product, a fruit-based product such as a fruit juice or a fermented juice, a vegetable-based product such as a vegetable juice or a fermented vegetable juice, a cereal-based product such as a chemically-acidified cereal product or a fermented cereal product, a rice-based product such as a chemically-acidified rice product or a fermented rice product, a nut-based product such as a chemically-acidified nut product or a fermented nut product a soy-based product such as a fermented soy milk product and any mixture thereof.
5 . The process according to any one of claims 1 to 4 , wherein said initial food product with a pH of between 3.4 and 4.6 is a dairy food product, in particular a fermented milk product, more particularly a yoghurt.
6 . The process according to any one of claims 1 to 5 , wherein said initial low-bacteria containing food product with a pH of between 3.4 and 4.6 is an initial food product treated so as to obtain a level of bacteria which is no more than 1×10 2 CFU per g of said initial low bacteria-containing food product, in particular an initial heat-treated food product.
7 . A process according to any one of claims 1 to 6 , comprising:
1) providing an initial food product with a pH of between 3.4 and 4.6;
1b) treating the initial food product so as to obtain a level of bacteria which is no more than 1×10 2 CFU per g of said initial low bacteria-containing food product, in particular by heat-treating said initial food product; and
2) adding to the initial low bacteria-containing food product one or more stable lactic acid bacteria in a total amount of at least 1×10 5 CFU per g, to obtain a food product stable at ambient temperature.
8 . The process according to any one of claims 1 to 7 , wherein said initial low-bacteria containing food product is a treated or heat-treated dairy food product, in particular a treated or heat-treated fermented milk product, more particularly a treated or heat-treated yoghurt.
9 . The process according to any one of claims 1 to 8 , said process comprising:
1a) producing an initial fermented milk, in particular an initial yoghurt, with a pH of between 3.4 and 4.6 by fermentation of a milk substrate;
1b) treating, in particular heat-treating, said initial fermented milk, in particular said initial yoghurt, so as to obtain an initial low bacteria-containing fermented milk, in particular an initial low bacteria-containing yoghurt containing a level of bacteria which is no more than 1×10 2 CFU per g; and
2) adding to the initial low bacteria-containing fermented milk, in particular to the initial low bacteria-containing yoghurt, one or more of stable lactic acid bacteria strains in a total amount of at least 1×10 5 CFU per g to obtain a fermented milk, in particular a yoghurt, stable at ambient temperature.
10 . The process according to any one of claims 1 to 9 , wherein the pH of said initial food product, in particular of the initial low bacteria-containing food product, is between 3.4 and 4.0, between 4.0 and 4.6 or between 3.6 and 4.2.
11 . The process according to any one of claims 1 to 10 , wherein said one or more of stable lactic acid bacteria are added to the initial food product, in particular to the initial low bacteria-containing food product, in a total amount of at least 5×10 5 per g, at least 1×10 6 per g, at least 5×10 6 per g or at least 1×10 7 CFU per g.
12 . The process according to any one of claims 1 to 11 , wherein said one or more stable lactic acid bacteria are added aseptically to the initial food product, in particular to the initial low bacteria-containing food product.
13 . The process according to any one of claims 1 to 12 , wherein said one or more of stable lactic acid bacteria is of the species Lactobacillus plantarum.
14 . The process according to claim 13 , wherein said one or more of stable lactic acid bacteria is selected from the group consisting of the strain DSM32493 deposited at the DSMZ on Apr. 26, 2017, a variant of the DSM32493 strain, the strain DSM33120 deposited at the DSMZ on May 22, 2019, a variant of the DSM33120 strain, the strain DSM33121 deposited at the DSMZ on May 22, 2019 and a variant of the DSM33121 strain, wherein said variant—when added in an amount of 1×10 7 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds—a) retains viability in an amount of at least 5×10 3 CFU/g after storing said test yoghurt 30 days at a temperature of 37° C.; and b) decreases the pH of said test yoghurt of at most 0.6 units after storing said test yoghurt 30 days at a temperature of 37° C.
15 . The process according to claim 14 , wherein said variant of DSM32493 is the DSM32493 strain into which the ATP synthase alpha subunit gene of the ATP-synthase operon bears the mutation G to A at its position 506.
16 . The process according to any one of claims 1 to 15 , wherein a food product is stable at ambient temperature when, after storing it for 180 days at a temperature of 25° C.:
its pH is not decreased more than 0.7 unit; and
the amount of stable lactic acid bacteria it contains is at least 1×10 3 CFU/g and/or is not decreased more than 3 log.
17 . A food product stable at ambient temperature, obtained by the process of any one of claims 1 to 16 .
18 . Use of one or more stable lactic acid bacteria for inoculation in a food product, in particular an initial low bacteria-containing food product, with a pH of between 3.4 and 4.6, wherein
(i) each of said one or more stable lactic acid bacterium is selected from the group consisting of strains of species Lactobacillus plantarum, Lactobacillus zymae, Lactobacillus rossiae, Lactobacillus collinoides, Lactobacillus similis, Lactobacillus versmoldensis, Lactobacillus acidipiscis, Lactobacillus hammesii, Lactobacillus namurensis, Lactobacillus nodensis and Lactobacillus tucceti; and
(ii) each of said one or more stable lactic acid bacterium, when added in an amount of 1×10 8 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds:
a) retains viability in an amount of at least 5×10 3 CFU/g after storing said test yoghurt 30 days at a temperature of 37° C.; and
b) decreases the pH of said test yoghurt of at most 0.6 units after storing said test yoghurt 30 days at a temperature of 37° C.,
19 . A Lactobacillus plantarum strain selected from the group consisting of the strain DSM33120 deposited at the DSMZ on May 22, 2019, a variant of the DSM33120 strain, the strain DSM33121 deposited at the DSMZ on May 22, 2019 and a variant of the DSM33121 strain, wherein said variant—when added in an amount of 1×10 7 CFU per g to a test yogurt having a pH of 4.3, previously heat-treated at 75° C. for 25 seconds—a) retains viability in an amount of at least 5×10 3 CFU/g after storing said test yoghurt 30 days at a temperature of 37° C.; and b) decreases the pH of said test yoghurt of at most 0.6 units after storing said test yoghurt 30 days at a temperature of 37° C.