IL130050A

IL130050A - Cheese of the fromage frais type

Info

Publication number: IL130050A
Application number: IL13005097A
Authority: IL
Original assignee: Nestle Sa
Priority date: 1996-12-23
Filing date: 1997-11-28
Publication date: 2001-10-31
Also published as: WO1998027825A1; AU5661998A; ATE218035T1; AU729924B2; TW534798B; BR9714428A; ES2175511T3; EP0949870B1; PT949870E; DE69712915T2; DE69712915D1; TR199901439T2; IL130050A0; EG21918A; EP0949870A1; DK0949870T3

Abstract

The invention concerns a method for preparing fresh cheese with a smooth texture and more than 13 % of dry matter, which consists in: fermenting milk with at least a strain of thermophilic lactic bacterium with short texture until a pH less than 4.9 is reached for obtaining curd, removing the resulting whey by continuous centrifuging at a rate higher than 500 l/h, never allowing the curd to be heated at more than 50 DEG C. The invention also concerns a non-refined cheese, obtainable by this method, having a smooth texture, and containing more than 13 % of dry matter and 10<4>-10<10> cfu/g of short textured thermophilic lactic bacteria which, when fermenting pasteurised milk containing 10 % of skimmed powder milk, 1 % of yeast extract and 0.5 % of glucose, at 40 DEG C up to 4.9 pH, provide the medium with a viscosity which is less than 50 mPaxs at a shearing speed of 290 s<-1>.

Description

130050/2 Cheese Of The Fromage Frais Type Societe des Produits Nestle S.A.

Fromage frais The subject of the present invention is a new fromage frais containing thermophilic lactic acid bac-teria, as well as a process for preparing it.

State of the art Unripened fromage frais-type cheeses include numerous types of products known by various names depending on the regions or countries. In Anglo Saxon countries, the name used is quarg or cottage cheese. In Germany, "quark" is used instead. Cheeses of this type are also known in the Scandinavian countries by the name of "viili" . Similar products are also found in Greece or in the Balkan States, these products being in particular related to set yoghurts.

In the traditional manufacture of fromage frais, a pasteurized milk is inoculated with a culture of mesophilic lactic acid bacteria which develops preferably at low temperature, rennet is optionally added, and the milk is incubated between 18°C and 35°C in order to obtain an essentially lactic acid curd in whey, that is to say a firm curd which is crumbly, porous and poorly contractile. Next, the whey is separated by centrifugation, by ultrafiltration or by draining through a filter, and the curd is recovered to which fat and/or flavouring may be added (Veisseyre, Technologie du Lait, Ed. La aison Rustique, Paris, pages 428-429, 604-609, 1975, I. S.B.N. 2-7066-0018-7).

During the preparation of a fromage frais, the separation of the whey by centrifugation is guided by the existence of a sufficient difference between the density of the curd and that of the whey. Furthermore, the texture of the curd should be such that it does not stick in the centrifuge (Veisseyre, Technologie du Lait, Ed. La Maison Rustique, Paris, p. 608, 1975, I. S.B.N. 2-7066-0018-7) .

The heat-sensitivity of the milk proteins can also be exploited, before separating the whey, in order to increase the dry matter content of the curd. To do this, the acidic curdled milk obtained after acidification with lactic acid is simply heated at 55-75°C for a few minutes, and then cooled to about 40°C. This heat treatment in fact makes it possible to modify the structure of the protein particles forming the curd, thus allowing better separation of the whey (FR 2361823; Tatini et al . , J. Dairy Science, 56, 815-825, 1971; A. Eck, Le Fromage, Ed. Lavoisier, Paris, pages 220-226, 1984, I. S.B.N. 2-85206218-6).

This heat treatment poses, however, other prob-lems. Indeed, the fromage frais practically no longer contains live lactic acid bacteria, which then poses problems of stability in respect of bacterial and fungal contaminants. To overcome this disadvantage, the cheese industry generally enriches the fromage frais, whose curd has been heated, with a fermented culture of lactic acid bacteria. As a guide, there may be mentioned the processes described by FR 2,361,823 (Westfalia) , WO 94/26124 (I.N.R.A.), EP 196436 (S.P.N.) , FR 2,342,666 (Fanni et al.) and US 4,191,782, for example.

On reading the literature, it is important to note that, in most cases, the cheese industry uses only mesophilic lactic acid bacteria for the preparation of a centrifuged fromage frais. These bacteria have an optimum growth at 18-35°C, they are rarely rope-forming or highly texturing, and there may be counted among them the species Leuconostoc citrovorum, Lactococcus lactis subsp. lactis, Streptococcus cremoris, Streptococcus lactis, Streptococcus diacetylactis, Lacto-bacillus casei subsp. casei and Lactobacillus sake, for example .

A few attempts have been made to industrially manufacture a fromage frais, which is fermented by thermophilic lactic acid bacteria and then centrifuged. These lactic acid bacteria have an optimum growth at 35-45°C, they are most often rope-forming and/or texturing, and there may be counted among them the species Streptococcus thermophilus, Lactobacillus delbruecki subsp. bulgaricus, Lactobacillus johnsonii , Lactobacillus acidophilus and Lactobacillus helveticus, for example. Unfortunately, as illustrated below, the industrial use of thermophilic lactic acid bacteria poses problems during the separation of the whey by centrifugation, because the density of the curd and that of the whey are not sufficiently different, and/or the curd has a sticky texture (Veisseyre, Technologie du Lait, p. 608) . A substantial part of the milk solids is thus lost in the whey.

For example, FR 2,354,711 (Unilever) and EP 144274 (J.-C. Pailler) thus propose to first concentrate a pasteurized milk, and then secondly to ferment this concentrated milk using thermophilic lactic acid bacteria. However, this cheese base is not satisfactory from the organoleptic point of view.

Likewise, EP 38940 (S.P.N.) proposes a process for the manufacture of a cheese spread in which a curd is formed by coagulation with thermophilic lactic acid bacteria in the presence of rennet, at a pH of between and 5.3, and the curd is drained by centrifugation. Unfortunately, if the coagulation occurs between pH 5 and 5.3, and if no salt is added, then the texture obtained is granular.

V.M. Wolpert also proposes another process in which a pasteurized skimmed milk is fermented with thermophilic lactic acid bacteria in the presence of rennet at 40°C to pH 4.65, the curdled milk is left to acidify at 17°C for 16-18 h to a pH of 4 , the whey is removed by centrifugation, the whey is ultrafiltered in order to recover the milk solids which were not precipitated during the centrifugation, and the retentate is incorporated into the curd so as to obtain a fromage frais having a standard dry matter content (Milk Industry UK, 90, No. 3, p. 29, 1988).

There may also be noted the work by Shah et al . who have analysed the effect of rennet on the formation of the curd. For that, they fermented a milk with thermophilic lactic acid bacteria to a pH of 4.5 in the presence of rennet, then they precipitated most of the milk solids with the aid of a laboratory centrifuge operating at 2000 g for 10 min (J. Food Science, 55, 398-454, 1990). The curd thus obtained has, neverthe-less, a very compact texture, due to the extensive cen-trifugation of the milk solids, which thus distinguishes it from commercially available fromage frais-type cheeses having a smooth texture.

In conclusion, to industrially manufacture a fromage frais having a high dry matter content, thermophilic lactic acid bacteria are rarely used, except in the case where the curd is ultrafiltered or simply drained (see J.L. Rasic, Cultures Dairy Products Journal, 22, p. 6-8, 1987; WO 9514389; EP 617899) . Indeed, the great majority of thermophilic lactic acid bacteria gives a curd which is unsuitable for industrial centrifugation, because the quantity of milk solids found in the whey exceeds acceptable standards. To overcome this disadvantage, the cheese industry conventionally resorts to ultrafiltration of the whey, as illustrated above by V.M. Wolpert, and/or to heating of the curdled milk to 55-75°C, as illustrated above by Tatini et al .

It has never been proposed to use a particular class of thermophilic lactic acid bacteria to solve these problems, in particular thermophilic lactic acid bacteria with a short texture.

Although the entire literature relating to fromage frais-type cheeses containing thermophilic lactic acid bacteria never specifies whether they are bacteria with a short texture or otherwise, there is very little chance that such bacteria have already been used to industrially prepare centrifuged fromage frais-type cheeses. Indeed, most species of thermophilic lactic acid bacteria exhibit the property of giving a degree of viscosity to their culture medium (see EP 750043; EP 699689; EP 97111381.6 and EP 97111379.0). For each species, a few strains nevertheless lack this property. These are called bacteria with a "short texture" .

The present invention therefore aims to use advantageously a minor class of thermophilic lactic acid bacteria to prepare a fromage frais having a high dry matter content .

Summary of the invention To this effect, the invention relates to a process for the preparation of a fromage frais having a smooth texture and more than 13% dry matter, in which a milk is fermented by at least one strain of thermophilic lactic acid bacterium with a short texture until a pH of less than 4.9 is reached so as to obtain a curdled milk, and the whey thus formed is removed by con-tinuous centrifugation at a throughput greater than 500 1/h, the curdled milk never being heated to more than 50°C.

The invention also relates to an unripened fromage frais, capable of being obtained according to the process of the invention, having a smooth texture, and containing more than 13% dry matter and 104-1010 cfu/g of thermophilic lactic acid bacteria with a short texture, that is to say bacteria which, when they ferment a pasteurized milk containing 10% of a skimmed milk powder, 1% of yeast extract and 0.5% of glucose, at 40°C to pH 4.9, give a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1.

Detailed description of the invention Against all expectations, it has been observed that it is possible to avoid heating a curdled milk to 55-75°C before removing the whey therefrom. Thermophilic lactic acid bacteria with a short texture make it possible to obtain a curd, suitable for centrifuga-tion, having two distinct phases easily separable by centrifugation. In addition, the curd does not clog the centrifuge.

It is thus possible to obtain a fromage frais which comprises all the major milk constituents, which gives a particularly balanced food. In addition, this cheese comprises live thermophilic lactic acid bacteria. It is not therefore essential to enrich this milk with a culture of lactic acid bacteria.

Milk is intended to designate, on the one hand, a milk of animal origin, such as cow's, goat's, sheep's, buffalo's, zebu's, horse's, ass's or camel's milk and the like. This milk may be a milk in the native state, a reconstituted milk, a skimmed milk, or a milk supplemented with compounds necessary for the growth of bacteria, for the treatment of the milk, or for the final qualities of the fromage frais, such as fat, yeast extract, peptone and/or a surfactant, for example .

The term milk also applies to what is commonly called a vegetable milk, that is to say an extract of plant materials, treated or otherwise, such as legumes (soyabean, chickpea, lentil and the like) or oilseeds (rapeseed, soyabean, sesame, cotton and the like) , which extract contains proteins in solution or in col-loidal suspension, coagulable by chemical action, by acid fermentation and/or by heat. It has been possible to subject these vegetable milks to heat treatments similar to those for animal milks. It has also been possible to subject them to treatments which are spe-cific to them, such as decolorization, deodorization, and treatments for eliminating undesirable tastes. Finally, the word milk also designates mixtures of animal milks and vegetable milks.

This milk should be pasteurized, that is to say should have undergone a heat treatment and/or a high-pressure treatment which has inactivated all living microorganisms. These techniques are well known to persons skilled in the art.

The pasteurized milk is then inoculated with an inoculum of thermophilic lactic acid bacteria with a short texture. Although the literature relating to thermophilic lactic acid bacteria rarely specifies if they are bacteria with a short texture or otherwise, there is very little chance that such bacteria are bac- teria with a short texture. Indeed, most species of thermophilic lactic acid bacteria exhibit the property of giving a degree of viscosity to their culture medium (see EP 750043; EP 699689; EP 97111381.6 and EP 97111379.0) . For each species, a few strains however lack this property. Persons skilled in the art are capable of screening among the species of thermophilic lactic acid bacteria those which have a short texture, particularly with the aid of the tests described below, for example.

This inoculum may be a culture in exponential growth phase, which is added to the pasteurized milk in an amount of 1 to 5% by weight, for example. It may also be a frozen or dried culture which is added directly to the milk in an amount of 0.01 to 0.1% by weight, for example. The techniques for preparing a bacterial inoculum are well known to persons skilled in the art. As a guide, there may be mentioned the techniques described ' in EP 688864 (S.P.N.) and EP 96201922.0 (S.P.N.) .

There is used at least one strain of thermophilic lactic acid bacterium with a short texture, that is to say a lactic acid bacterium having an optimum growth at 35-47°C, which is capable of not clogging a centrifuge when it is used in the process according to the invention.

In general, these bacteria are not rope-forming. These species therefore do not have the ability to form a sticky material in various media such as milk and serum. The non-rope -forming character of the milk fermented by a thermophilic bacterium with a short texture can be observed and determined as described below. 1. By observing the structure of acidified milk compared with that of milk acidified with non- rope-forming cultures. The non-ropey milk adheres to the walls of a glass pot, whereas ropey milk coheres onto itself. 2. Another test may be performed with a pipette.

The pipette is dipped into acidified milk which is aspirated in a quantity of about 2 ml, and then the pipette is withdrawn from the milk. Ropey milk forms a rope between the pipette and the liquid surface, whereas non- ropey milk does not give rise to this phenomenon. When the liquid is released from the pipette, the non-ropey milk forms separate droplets just like water, whereas the ropey milk forms droplets ending with long ropes which end at the tip of the pipette. 3. When the test tube filled roughly to a third of its height is stirred with the aid of a rotary stirrer, the non-ropey milk rises on the inner surface of the wall, whereas the rise of ropey milk is practically zero.

The "short texture" character of thermophilic lactic acid bacteria can also be determined with the aid of rheological measurement parameters. Indeed, the texture of an acidified milk can be characterized by its viscosity. A few commercial apparatus are capable of determining this parameter, such as the Bohlin VOR rheometer (Bohlin GmbH, Germany) . In accordance with the supplier's instructions, the sample is placed between a plate and a truncated cone of the same diameter (30 mm, angle of 5.4°, gap of 0.1 mm), then the sample is subjected to a continuous rotating shear speed gradient which forces it to flow". The sample, by resisting deformation, develops a tangential force called shear stress. This stress, which is proportional to the flow resistance, is measured by means of a torsion bar. The viscosity of the sample is then determined, for a given shear speed, by the ratio between the shear stress (mPa) and the shear speed (s"1) . numerous trials of rheological measurement of the "short texture" character with various thermophilic strains with a short texture led to the following definition. A thermophilic lactic acid bacterium with a short texture can be a thermophilic bacterium which, when it ferments a medium appropriate for its growth at an optimum pH for the production of a high viscosity, gives a viscosity to the medium which is less than 50 mPa- second at a shear speed of the order of 290 s"1.

More particularly, they are bacteria which, when they ferment a pasteurized milk containing 10% of a skimmed milk powder, 1% of yeast extracts and 0.5% of glucose, at 40°C to pH 4.9, give a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1, for example.

Among the thermophilic lactic acid bacteria with a short texture, the best results for carrying out the present process have been obtained with the Lactobacillus johnsonii CNCM 1-1225 strain. Other strains can also be used, in particular the Lactobacillus bulgaricus YS4 and YL8 strains mentioned in Example 3 below.

It should be noted that the Lactobacillus johnsonii CNCM 1-1225 strain has advantages which are specific to it. It is a probiotic lactic acid bacterium which has already been described in EP 577904. The invention is therefore intended most particularly to use probiotic thermophilic lactic acid bacteria with a short texture, that is to say lactic acid bacteria which are capable of adhering to human intestinal cells, of excluding pathogenic bacteria from human intestinal cells, and of increasing the property of the human body to defend itself against pathogens, for example by increasing the phagocytosis capacities of the granulocytes derived from human blood (J. of Dairy Science, 78, 491-197, 1995; immunomodulation capacity of the La-1 strain which has been deposited at the Pasteur Institute under the number CNCM 1-1225) .

The milk is then fermented until a coagulum is formed at a pH of less than 4.9. This fermentation is intended to cause the casein to pass from a colloidal phase to a precipitated phase, this passage being accompanied by the formation of a liquid called whey or milk serum. If the curd is obtained exclusively by acid fermentation, it is preferable to add to the milk, before or after pasteurization, 50-300 ppm of calcium chloride so as to ensure optimum contraction of the curd, which correspondingly subsequently promotes the separation of the whey.

Most often, it is preferable to obtain a curd by fermentation combined with an enzymatic action. There may therefore be added to the milk, after pasteurization, 0.005 to 0.1% by volume/volume of rennet. Rennet is the coagulating agent traditionally used for the coagulation of milk for the manufacture of cheese. The name "rennet" is given to the coagulating extract obtained from the abomasum of young ruminants killed before weaning. It contains in reality two active frac-tions, one, which is major, consisting of chymosin, and the other, which is minor, of pepsin.

Within the framework of the present invention, it will be accepted that rennet also encompasses calf rennet substitutes, such as animal pepsins; the coagu-lating preparations obtained from the plant kingdom extracted from artichoke, thistle, ficin, latex, fig, papain, for example; coagulating preparations obtained from the microbial kingdom, extracted from bacteria of the genus Bacillus and Pseudomonas, and from moulds belonging to the species Endothia parasitica, Mucor pusillus and Mucor miehei, for example.

The fermentation of milk may also be carried out in the presence of rennet and calcium chloride in the proportions indicated above, for example.

The whey is then removed by continuous industrial centrifugation at a throughput greater than 500 1/h, preferably greater than 5000 1/h. Persons skilled in the art know well the various centrifugation systems applied to curdled milk. As a guide, there may be mentioned the apparatus described in FR 2,361,823; A. Eck, Le Fromage, Ed Lavoisier, Paris, 1984, I. S.B.N. 2-85206218-6, pages 220-226; and R. Veisseyre, Tech-nologie du Lait, Ed. La Maison Rustique, Paris, 1975, I. S.B.N. 2-7066-0018-7, pages 604-609.

To carry out the present invention, the curdled milk is not subjected to a temperature exceeding 50°C. Despite this, the loss of dry matter from the whey is marginal. The whey, after centrifugation, indeed con-tains less than 0.8% by weight of proteins, even less than 0.7%.

In a specific embodiment of the process according to the invention, after having separated the whey by centrifugation, it is also possible to add to the curd seasonings, flavourings, spices and/or colourings, or to- subject the curd to overrun or to inoculation with microorganisms capable of developing a flavour or a particular consistency, for example. In particular, the curd is mixed with 10-60% by weight of a milk fer-mented by lactic acid bacteria and/or with 0.1-15% by weight of milk cream, for example.

In another specific embodiment of the process according to the invention, a pasteurized skimmed milk is fermented by a thermophilic lactic acid bacterium with a short texture at 35-47°C to pH 4-4.9, in the presence of rennet and of 50-300 ppm of calcium chloride, and the whey is separated by centrifugation at 30-50°C.

The invention makes it possible to obtain an unripened fromage frais having at least 13% dry matter, 104-10x0 cfu/g of thermophilic lactic acid bacteria with a short texture, and a consistency characteristic of that of a fromage frais obtained after centrifugation or ultrafiltration of a milk curdled by mesophilic lactic acid bacteria. It has been observed that a dry matter content at least greater than 13%, particularly 13-30%, gives a smooth and unctuous cheese which is similar to a cream. On the other hand, a fromage frais having less than 13% dry matter is rather liquid, with a consistency close to that of a liquid yoghurt.

This fromage frais may comprise up to 1010 cfu/g of thermophilic lactic acid bacteria with a short texture. This characteristic clearly distinguishes it from industrial fromage frais type cheeses obtained after heating the curd to 55-75°C as described above. Indeed, it is not possible to reach such a concentration of bacteria if attempts are made to enrich a fromage frais with lactic acid bacteria, while observing the thre-shold value of 13% dry matter.

Finally, the fromage frais may also be used during the manufacture of¾ a more complex food composition, particularly as filling product, for example for preparing products based on cereals filled with fromage frais according to the invention. The process described in EP 358983 (S.P.N.) is particularly appropriate for preparing such products, for example.

The invention is described in greater detail below with the aid of the following additional descrip-tion which refers to a test for measuring the viscosity of an acidified milk, and to examples of preparation of fromage frais type cheeses . The percentages and the parts are given by weight unless otherwise indicated. It goes without saying, however, that these examples are given by way of illustration of the subject of the invention and do not constitute in any manner a limitation thereof.

Test for measuring the viscosity A milk is prepared containing 10% of a skimmed milk powder, 1% of yeast extracts and 0.5% of glucose, it is pasteurized at 95°C for 30 min, and it is fermented at 40°C with a strain of thermophilic lactic acid bacterium to a pH of 4.9. 100 g of sample are collected in a beaker, it is pre-sheared at 300 revolutions/min for 60 seconds with the aid of a mixer (Heidolph mixer, Germany) , it is stored in a refrigerator at 4°C for 1 hour, then it is placed at 15 °C between the plate and the cone of the Bohlin VOR rheometer (Bohlin GmbH, Germany; system of measurement CP5/30: cone with a diameter of 30 mm, cone angle relative to the plate of 5.4°, cone-plate gap of 0.1 mm).

The sample is then subjected to a shear speed gradient, operated by the continuous rotation of the plate, which forces it to flow between the cone and the plate. By resisting the deformation, the sample then develops a tangential force called shear stress. This stress, which is proportional to the flow resistance, is measured by means of a torsion bar mounted on the cone which is sensitive to a torsional force. The viscosity of the sample is then determined, for a shear speed varying from 4.645 to 293.1 s"1, by the ratio between the shear stress (mPa) and the shear speed is"1) .

Under these conditions, the Lactobacillus johnsonii CNCM 1-1225 strain gives a viscosity to the medium of the order of 30 mPa-s at a shear speed of 290 s"1.

For comparison, under the same conditions, the texturing strains Streptococcus ther ophilus CNCM I-1421, Lactobacillus bulgaricus CNCM 1-1724, Lactobacillus bulgaricus CNCM 1-800, Lactobacillus bulgaricus CNCM 1-1198, mentioned respectively in EP 688864, EP 638642, EP 367918, EP 564965, give a viscosity to the medium, respectively, of the order of 80, 100, 110 and 130 mPa-s at a shear speed of 290 s"1.

Example 1 3% of a fresh preculture, in MRS medium, of the Lactobacillus johnsonii CNCM 1-1225 strain is mixed with sterile MSK medium comprising 10% reconstituted powdered skimmed milk, 0.1% commercial yeast extract, 0.5% peptone and 0.1% Tween 80, then it is fermented for 8 hours at 40°C, without mixing.

A large-scale culture of this strain is then prepared using a skimmed milk, pasteurized at 88 °C for 2 min, comprising 0% fat, 9% dry matter. For that, this milk is inoculated at 40°C with 5% of the preculture described above, 150 ppm of calcium chloride and 10 ppm of calf rennet. It is fermented to a pH of 4.5 (16 hours) . The milk then separates into two distinct phases consisting of a curd and a whey. Then the curdled milk is centrifuged directly, at 40°C, at 8500 rpm (rotations per min) in a Westfalia® centrifuge (Germany) . A curd having 15.5% dry matter and about x 108 cfu/g is finally recovered. The whey contains about 0.66% by weight of proteins.

For comparison, a fromage frais is prepared traditionally by fermenting at 23-27°C to pH 4.4 the same skimmed milk, in the presence of rennet, with two commercial strains of mesophilic lactic acid bacteria. The curdled milk is heated at 60°C for 2 min, then it is cooled to 40°C. The heated curdled milk is centri-fuged at 40°C and at 8500 rpm in a Westfalia® centri-fuge, and a curd having 15.5% dry matter and less than 103 cfu/g of live bacteria are recovered.

The results show that it is possible to prepare a curd comprising 5 x 108 cfu/g of thermophilic lactic acid bacteria, without significantly losing the protein material during the centrifugation. Indeed, the dry matter content obtained for the comparative fromage frais is identical to that comprising thermophilic bacteria. After cooling to 10°C, the curd exists in the form of a malleable paste, which can be consumed as a low-fat fromage frais.

Example 2 The fromage frais obtained in Example 1 is mixed with 20% commercial yoghurt LCI® (HIRZ®, Switzerland) , which comprises the Lactobacillus john-sonii CNC 1-1225 strain, and 8% milk cream containing 40% fat. A malleable paste is obtained which can be consumed as a high- fat fromage frais.

Example 3 A fromage frais is prepared as described in Example l, the only difference being that the milk is fermented with the Lactobacillus bulgaricus YS4 and YL8 strains with a short texture, that is to say strains which, when they ferment a pasteurized milk containing 10% of a skimmed milk powder, 1% of yeast extracts and 0.5% of glucose, at 40°C to pH 4.9, give a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1.

For each fromage frais thus obtained, the results are similar to those observed in Example 1.

Claims

1. Process for the preparation of a fromage frais having a smooth texture and more than 13% dry matter, in which a milk is fermented by at least one strain of thermophilic lactic acid bacterium with a short texture until a pH of less than 4.9 is reached so as to obtain a curdled milk, and the whey thus formed is removed by continuous centrifugation at a throughput greater than 500 1/h, the curdled milk never being heated to more than 50°C.

2. Process according to Claim 1, in which the thermophilic lactic acid bacterium with a short texture is a bacterium which, when it ferments a medium appropriate for its growth at an optimum pH for the production of a high viscosity, gives a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1.

3. Process according to Claim 2, in which the thermophilic lactic acid bacterium with a short texture is a bacterium which, when it ferments a pasteurized milk containing 10% of a skimmed milk powder, 1% of yeast extracts and 0.5% of glucose, at 40°C to pH 4.9, gives a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1.

4. Process according to Claim 3, in which the thermophilic lactic acid bacterium with a short texture is the Lactobacillus johnsonii CNCM 1-1225 strain.

5. Process according to Claim 1, in which the milk comprises 50-300 ppm of calcium chloride.

6. Process according to Claim 1, in which the milk comprises 0.005 to 0.1% by volume/volume of rennet.

7. Process according to Claim 1, in which, after having removed the whey by centrifugation, the curd is mixed with 10-60% by weight of a milk fermented by lac-tic acid bacteria.

8. Process according to Claim 1, in which, after having removed the whey by centrifugation, the curd is mixed with 0.1-15% by weight of milk cream.

9. Process according to one of Claims 1 to 6, in which skimmed milk is fermented by a thermophilic lactic acid bacterium with a short texture at 35-47°C to pH 4-4.9, in the presence of rennet, and the whey is separated by centrifugation at 30-50°C.

10. Unripened fromage frais, capable of being obtained according to the process described in one of Claims 1 to 9, having a smooth texture, and containing more than 13% dry matter and 10" -1010 cfu/g of thermophilic lactic acid bacteria with a short texture, that is to say bacteria which, when they ferment a pasteurized milk containing 10% of a skimmed milk powder, 1% of yeast extracts and 0.5% of glucose, at 40°C to pH 4.9, give a viscosity to the medium which is less than 50 mPa-s at a shear speed of 290 s"1. FOR THE M»PUCANT: Dr. Yttz ^ ti iS & Pai