FR3033125A1 - FOOD ARTICLE COMPRISING AT LEAST ONE CUT AND PACKED PORTION OF A SOFT AND FROZEN PASTE CHEESE AND METHOD FOR PRESERVING THE SAME. - Google Patents

Abstract

The present invention relates to a packaged food article comprising at least one cut portion of a soft cheese having a crust and a crust-free sliced surface exposing said dough which can be stored under satisfactory conditions long after cutting, and a method of long conservation of said at least a portion in a closed package enveloping thereof. This food article comprises said at least one portion and a packaging (1) closed wrapping and having at least one permselective wall (3) adapted to control oxygen and carbon dioxide content defining an internal atmosphere to packaging by gas exchange with the outside, so that after a shelf life of at least three weeks after cutting the portion, the crust has a maintained metabolic activity and the sliced surface is substantially virgin of undesirable microorganisms. According to the invention, the cheese is washed rind and the oxygen content by volume is less than 1% during the shelf life.

Description

FOOD ARTICLE COMPRISING AT LEAST ONE CUT AND PACKED PORTION OF A DOUBLE AND LAVED CRUSHED CHEESE, AND METHOD FOR PRESERVING THE SAME.

The present invention relates to a packaged food article comprising at least one cut portion of a soft cheese having a crust and a crust-free sliced surface exposing said dough which can be stored under satisfactory conditions long after cutting, and a method of long conservation of said at least a portion in a closed package enveloping thereof. The invention applies in particular, but not exclusively, to such portions packaged in trays closed by lids. It is known from document EP-B1-1277445 to keep in a package formed of a tray closed by a through microperforation seal, for several weeks after cutting, cut portions of a soft cheese and crust specifically of the non-mixed flowering type (this flowered crust comprising a mold consisting of Penicillium with possibly Geotrichum, and being devoid of coryneform bacteria and micrococci), by controlling the concentrations of oxygen and carbon dioxide inside the packaging to maintain a substantially constant activity of microorganisms on the crust of these portions and on the contrary inhibit on their sliced surfaces so that they are not the seat of a regrowth by fermentation. For this purpose, this document teaches to use initial voluminal contents (OJ day) of oxygen and carbon dioxide inside the package respectively greater than 2% and greater than 20 ° A and then to control these contents. oxygen and carbon dioxide so that they are respectively between 1 and 3% and between 15 and 30% for a shelf life of at most three weeks (day J21). A major disadvantage of the packaging presented in this document is that, on the one hand, the conservation conditions that it recommends 3033125 2 are strictly limited to cheeses with a rind of flowers and, on the other hand, their shelf life obtained without altering the crust and without regrowth on the wafer is relatively reduced, not exceeding three weeks after cutting.

An object of the present invention is to provide a food article which overcomes this disadvantage, and this object is achieved in that the Applicant has unexpectedly discovered that the maintenance of an internal atmosphere around a portion packaged with a soft cheese specifically washed rind particular defined by a content by volume (v / v) oxygen less than 1%, allows to keep this portion satisfactorily for a period of at least three weeks and advantageously at least six weeks after cutting, disposing at the end of this period of a "living" crust (ie with keeping alive strains of microorganisms ripening in the crust) and a slice 15 on the contrary free a development of these microorganisms (ie substantially without regrowth on slice). A food article according to the invention thus comprises: at least one cut portion of a soft cheese having a crust and a sliced surface devoid of crust exposing said paste, and a closed package wrapping said at least one portion and having at least one permselective wall adapted to control oxygen and carbon dioxide volumetric contents defining an inner atmosphere of the package by gaseous exchange with the outside of the package, so that after a packaged shelf life of at least three weeks after cutting said at least a portion, the crust has a maintained metabolic activity and the sliced surface is substantially virgin undesirable microorganisms, and this article is such that the cheese is crust washed and that the oxygen (non-zero) volume content is less than 1% during the shelf life.

By "soft cheese" is meant in known manner a cheese whose consistency or firmness of the dough, defined by the percentage of water content in the defatted cheese (TEFD), is greater than 67 (for example a pie chart, but not limited to), this percentage being calculated according to paragraph 7.1.1. of the general standard for CODEX cheese STAN A-6-1978, Rev. 1-1999. As stated in this standard, the TEFD (%) is equal to 100 x (weight of water in cheese) / (total weight of cheese - weight of fat in cheese).

The term "washed rind cheese" is also understood to mean, in a known manner, a cheese whose rind has undergone, during the ripening, washes and brushings which favor the development of a more pronounced taste (usually by means of a washing operation). repeated with warm salt water to destroy the crust mold) and which give this crust a moist and sticky nature (which sticks to the fingers) and a color usually going from yellow to red through orange . These washed rind cheeses are thus characterized in particular by: the double absence in their crust, on the one hand, of mold such as Penicillium and, on the other hand, of Geotrichum such as Geotrichum candidum (species usually listed between molds and yeast that is absent or present only in the form of traces hardly expressing itself). The washed rind of the portions that can be used in the invention is therefore in particular free of Penicillium candidum; and by the fact that their crust comprises, on the one hand, coryneform bacteria such as Brevibacterium linens (preferably being free of micrococci) and, on the other hand, yeasts such as, for example, Debaryomyces (e.g. Debaryomyces hansenil). Examples of soft cheeses and washed rinds that can be used in the form of sliced portions in an article 30 according to the invention are the following non-limiting list: Aisy ash, Ami du Chambertin, Boulette d'Avesnes, Chamberat Farmer, Stubble, Heart of Arras, Nantais parish priest, Dauphin, Époisses (PDO), Herve cheese (PDO), 3033125 4 Beaufortain grater, Kénogami, Langres farmer (AOC), Limburger, Livarot (AOC), Maroilles (AOC) ), Mont d'Or or Vacherin Mont-d'Or in Switzerland and Vacherin du Haut Doubs (AOC) in France, Munster (AOC), Géromé, Niolo, Pavé d'Auge, Petit Gaugry, Foot-Wind, Bridge the bishop (AOC), Rodoric, Rollot, Soumaintrain, Taleggio, Trou du Cru, Vieux-Lille. In the present description, the term "sliced surface" is understood to mean all the cut and crust-free faces that the or each portion has, faces that are for example two in number forming a dihedral in the case of a cut portion of triangular section.

Advantageously, said volume content of oxygen may be less than 0.5% and is preferably less than or equal to 0.2% during said shelf life. According to another characteristic of the invention, said volume content of carbon dioxide may be between 9 and 16 ° A and advantageously between 12 and 14 °) / 0 during said shelf life. Even more advantageously, said internal atmosphere may have said combined volumetric oxygen and carbon dioxide contents during said shelf life which is at least four weeks and preferably at least six weeks.

It will be noted that this combination of ranges of oxygen contents and carbon dioxide makes it possible to obtain this very long shelf-life of six weeks or more for the articles according to the invention, which results in particular at the end of this period. duration by an absence of fermented odor and regrind on slices at the opening of the package, 25 as well as a satisfactory texture and taste of the crust, and that this period of good conservation is significantly higher than those obtained at this day in such visual, olfactory and taste conditions of crusts and slices. According to another aspect of the invention, said at least one wall 30 with selective permeability may have, for obtaining said internal atmosphere including these oxygen and carbon dioxide contents, non-traversing microperforations which only open towards inside the package, in an inner face of said at least one wall. Advantageously, said at least one permselective wall may comprise: at least one flexible film (for example made of plastic or a biodegradable material) which is turned towards the inside or the outside of the package and which has said microperforations, and - at least one non-perforated porous layer, which overcomes said at least one film and is turned towards the outside or inside of the package (the opposite of said at least one film). Even more advantageously, said microperforations may each have a larger transverse dimension of between 50 μm and 1000 μm and may be arranged in the form of straight, curved or broken lines spaced apart from each other.

According to another preferred feature of the invention, the package may comprise a tray (preferably made of a plastic material such as compact polystyrene, or a biodegradable material such as starch), and a permeability wall. selective which is heat-sealed on a rim of said tray by said at least one film, for example polyester. By "tray" is meant in the present description a hollow container comprising a bottom for supporting the or each portion of cheese and a substantially vertical or oblique peripheral side wall, this wall and the cover overlying it being substantially shaped circular, oval, square, rectangular or other. Advantageously, said at least one porous layer may comprise a sheet of a cellulosic material which absorbs the moisture of said at least one portion and of said internal atmosphere and which is preferably made of paper, said at least one portion and said internal atmosphere 30 can then be the seat of a substantially constant loss of moisture during said shelf life.

According to an exemplary embodiment of the invention, said permselective wall further comprises: an adhesive, for example of polyurethane type, interposed between said at least one porous layer which has a gramrnage for example between 20 and 70; g / m2, and said at least one film having a thickness for example between 5 pm and 20 pm, and - a sealing varnish interposed between said at least one inner film and said flange. A preservation method according to the invention for at least three weeks after cutting, at least one cut portion of a soft cheese in a package controlling oxygen and carbon dioxide volume contents within the packaging by gaseous exchange with the outside of the package, so that said at least one portion has, at the end of said weeks, a crust with a metabolic activity maintained and a trench surface free of crust exposing said paste being substantially free of undesirable microorganisms, is such that said cheese is washed rind and that said oxygen content by volume is less than 1% during said weeks. Advantageously, this process according to the invention makes it possible to preserve the said at least one portion for at least six weeks after cutting, and is such that the oxygen content by volume is less than 0.5% and preferably less than or equal to 0, 2 ° A, and that the volume content of carbon dioxide is between 9 and 16% and preferably between 12 and 14%.

Also advantageously, the inside of the package is subject to a loss of substantially constant humidity during said weeks after cutting resulting in a relative loss of weight for said at least one portion for example of the order of 0 , 1 to 0.2% per week, so that the presence of water droplets inside the package and an alteration of said crust at the end of said weeks is avoided.

Other features, advantages and details of the present invention will become apparent on reading the following description of several embodiments of the invention, given by way of non-limiting illustration, said description being made with reference to the accompanying drawings. 1 is a top and perspective view of a sealed container package according to an exemplary embodiment of the invention; FIG. 2 is a diagrammatic view illustrating the four layers that can be used to form an operculum; closing a tray of a package according to the invention, such as that of Figure 1, Figure 3 is a schematic plan view of a width from a coil and used to form a perforated film included in such a cap according to the invention, FIG. 4 is a graph showing the evolution, after smoothing, of the oxygen content content maintained in such a sealed container package, in FIG. the number of days after cutting a portion of a cheese according to the invention contained in this package, and FIG. 5 is a graph showing the evolution after smoothing of the carbon dioxide content by volume in the same package containing the same portion, depending on the number of days after cutting. Packaging 1 of FIG. 1 is specially adapted to contain a soft cheese with washed rind and comprises a tray 2, for example made of plastic or biodegradable material (eg in a compact polystyrene, ie not expanded) closed at its rim 2a by a selective permeability seal 3. The lid 3 is heat-sealed on the flange 2a, for example at 210 ° C. under a pressure of 7 to 8 N / 15 mm, and it has non-through microperforations 4 which open only inside the package 1 .

This lid 3 comprises, from the inside to the outside of the package 1, in the example of FIG. 2: a sealing varnish 3a of the lid 3 on the flange 2a which presents, for example a thickness of 1 μm and a basis weight of 2 g / m 2; a flexible film 3b made of plastic or biodegradable material, for example made of isotropic polyester, which has through microperforations 4 (visible in FIG. 3) and for example a thickness of 12 μm and a basis weight of 17 g / m 2, an adhesive 3c, for example of polyurethane type, of a thickness equal to 3 μm and a grammage equal to 3 g / m 2, and a non-perforated cellulosic porous layer 3d by io example of bleached Kraft paper, having a thickness of 43 IJM and a basis weight of 43 g / m2, and which defines the outer face of the lid 3. The film 3b illustrated in the example of Figure 3 shows a width resulting from a coil and having a length L of 435 mm. This film 3b has microperforations 4 which each have a larger transverse dimension of about 100 μm (eg the diameter in the case of circular microperforations 4, or a diagonal in the case of polygonal microforforations 4, for example rectangular or square). and which in this example are arranged in the form of series of parallel straight lines. These lines 5 are in this embodiment spaced apart from each other by a distance d of 10 mm. The seal 3 according to the invention has, for example, a water vapor permeability (PVE) measured at 38 ° C. and at 90% relative humidity (RH) of between 45 and 70 g / m 2 / day.

Retention trials of soft-cheeses and washed rind portions of the description "Bread of Stubble" and "Thatch" in "control" packages and according to the invention: Conservation tests were carried out by varying in the same package according to FIGS. 1-3 the voluminal contents (v / v) of oxygen (O 2) and of carbon dioxide (CO 2) around a cut portion of a soft cheese with a washed rind of denomination either 3033125 9 "Thatched Bread" or "Thatch." Table 1 below lists the results obtained, with for the "control" tests of the shaded lines and for the tests according to the invention of non-gray lines. Table 1 shows respectively the packaged and unpacked aspects of the preserved portions, with a gradation of these aspects on a scale of 1 to 4 for the crust appearance (satisfactory for 4) and the intensity of the crust. regrowth on slices (no regrowth for 4) and with the abbreviation "RAS" for nothing to report.

10 Table 1: Appearance Packed% CO2 (v / v) Age at tasting (days after cutting Number of servings packed Cutting age (days) 4 rriais gbOtlaible Bread Stubble Bread Canes Stubble 2 kg Culms Big Size Slices 0.11 17.5 0.25 18.1 0.15 15.5 0.16 13.1 3 (yellow) Odor a 2 (slightly sticky crust) OK Odor slightly strong Culms 2 kg D + 12 Culms 2 kg D + 18 Stubble 2 kg PSP A3 Stubble Bread 0.12 16.5 0.137 13.1 6.347 3 (Lightweight 2. (Crust Regrowth Stubble 4 Large Stubble Culms Stubble 2 kg D + 12 Stubble 2 kg D + 18 Stubble 2 kg 21 15 PSP A3 12 0.043 0.316 12 003 1 OK but clear Slightly regrow OK 3 (margin read a little) 3. (Mmb.a little Crust: 4, Regrowth: 4, 2.9 Cheese 45 34 Appearance Unpacked 3033125 10 morge wet, a little spindly Stubble 2 kg 21 24 12 0.08 10.1 Crust: 3 PSP A3 Regrowth: 4 Smell slightly fermented, light yellow barley, moist Bread of 21 15 6 0.11 15.1 Crust : 4; Regrowing stubble: 3; Slice matte appearance, not shiny, light yellow Bread 21 22 6 0.09 13.5 No defects Stubble Bread 45 15 6 0.22 17.2 Crust: 4; Regrowing stubble: 3; Appearance slice matte, not glossy, light yellow Culms 2 kg 12 15 12 0.03 8.6 Crust: 4; Regrowth: 4 (0K) Culms 2 kg 12 24 12 0.05 9.2 Crust: 4; Regrowth: 4 (Light Morge) Culms Large Size 28 15 6 0.38 14.3 Crust: 4; Regrowth: 4 (0K) Culms 2 kg 18 15 12 0.1 14.2 Crust: 3 (damp morge) Culms 2 kg 18 25 12 0.16 15.4 Very wet morge: Culms 2 kg 11 25 12 0.11 13.5 Few margin but not wet Culms 2 kg 11 25 12 0.13 10.2 Morge slightly moist paste Bread of 19 15 10 0.06 11.6 Crust: 4 (slab slightly moist): same TRC at age Pack Bread 19 25 10 0.16 12.8 Thick Morge Culms Stubble 2 kg 19 15 12 0.09 13.9 Wet Morge Stubble 2 kg 11 15 12 0.06 9 Low color but margin OK Culms 2 kg 21 43 12 0.26 14.8 OK 4 PSP A3 Stubble 2 kg 12 43 12 0.04 5.3 OK 4 Thatch 2 kg 18 36 0.29 16.3 OK 3 (wet) A3 Stubble 2 kg 12 36 0.13 13.5 OK 4 (slightly damaged) A3 Stubble 2 kg 19 36 0.117 15 OK 4 A3 3033125 11 Stubble 2 kg 21 22 12 0.105 14.8 OK 4 Thatch 2 kg 15 22 12 0.06 9.7 OK 4 Thatch 2 kg 16 14 11 0.05 15.3 OK 3 (pale) A3 Stubble 2 kg 16 14 12 0.09 13.5 OK 3 (wet) B11 Bread of 50 14 6 0.04 11.4 OK = 3 (slimy ) Culms Thatches 2 kg 11 35 12 0,187 12 aspect: 4; regrowth: 4 Bread 19 35 10 0.098 12.2 aspect: 4; Culms regrowth: 4 Culms 2 kg 21 35 12 0.059 9.4 = 4 PSP A3 Bread of 21 35 6 0.154 9.1 4 Stubble Bread of 45 35 6 0.054 9.7 4 Culms Culms 2 kg 12 35 12 0.051 6.7 3 Culms Large Size 28 35 6 0.184 14.7 3 (wet morge) Culms 2 kg 19 24 12 0.14 16.6 Crust Appearance: 3 (slightly humid) Culms 2 kg 11 24 12 0.18 14.5 Appearance crust: 4 (not wet, shiny) Stubble 2 kg 18 44 12 0,139 15,2 Rind a little too wet Stubble 2 kg 11 44 12 0,21 13,8 Crust not colored enough, a little dry Pairi, key 50. 37 12 0 10.5 Culms Culms 2 kg 19 44 12 0.244 13 OK Culms 2 kg 11 44 12 0.16 12 OK Bread of 50 44 12 0.011 10.7 OK Culms Culms 2 k9 21 37 12 0.138 13 OK Morge OK Culms 2 kg 15 37 12 0.231 14.1 OK Color a little pale Culms 2 kg 20 29 11 0.026 10 OK Culms 2 kg 16 29 12 0.113 14.4 OK Culms 2 kg 27 14 12 0.096 14.1 OK Morge OK Culms 2 kg 27 14 12 0.053 12.7 OK E Fatty, moist / very beautiful color Bread of 49 14 12 0.05 10.6 OK Culms Culms 2 kg 21 59 12 0.12 13.4 Appearance: 2 PSP A3 (wet, pale, crystallized); regrowth: 4 Bread of 21 59 6 0.113 13.7 Appearance: 3 (damp morge); Culms 3033125 12 Regrowth: 4 Stubble 2 kg 18 45 12 0.03 10.8 Appearance: 3; Regrowth: 4 Stubble 2 kg 11 45 12 0.317 12.9 Bread 19 52 10 0.095 11.8 = Regrowth: 4 Thatch Stubble 2 kg 19 45 12 0.092 12.1 Appearance: 3.5 (damp morge, light mast); Regrowth: 4 Stubble 2 kg 11 45 12 0.106 11 Regrowth: 4 Bread 50 45 12 0.01 11.6 Regrowth: 4 Thatch Culms 2 kg 21 35 21 0.058 12 Appearance: 3 (wet): Regrowth: 4 Stubble 2 kg 15 35 50 0.059 9.07 Appearance: (too pale but not moist) Culms 2 kg 20 11 0.01 12 Appearance: 3.5 (moist crust); Regrowth: 4 Culms 2 kg 20 12 0.07 11.4 Appearance: 3.5 (moist crust); Regrowth: 4 Culms 2 kg 16 12 0.05 10.9 Regrowth: 4 Bread of 50 23 0.02 13.1 Culms Culms 2 kg 27 15 12 0.08 15.6 Appearance: 4 (nice color, not wet) ; Regrowth: 4 Stubble 2 kg 27 15 12 0 14.4 Appearance: 4 (nice color, light weight margin); Regrowth: 4 Bread of 49 15 12 0.03 12 Thatch Culms 2 kg 12 60 12 0.431 17.9 OK Light Morge, odor Culms Culms 2 kg 21 60 12 0.442 16.1 OK Morge, smell Culms Culms 2 kg 21 42 12 0.419 16.3 OK Culms 2 kg 15 42 12 0.25 12.1 OK No visible regrowth, some white spots Morge too sticky 1 25 16 OK, Culms 2 kg 20 34 12 Culms 2 kg 16 34 12 0.05 10 , 2 OK Bread of 50 34 6 0.105 13 OK Bread Bread of 50 27 0.096 13.9 OK Culms Culms 2 kg 21 14 12 0.081 14.2 OK 3033125 13 These tests show, in particular, the beneficial effect on good up to and including six weeks (up to 42 days) up to the best before date of use of the article ("DLUO" for short), from an internal atmosphere to the packaging characterized by a volume content in stable oxygen and less than 1%, preferably 0.5% and even more preferably 0.2%, and the even more positive effect of a joint carbon dioxide content e stable and between 9 and 16% and advantageously between 12 and 14 ° / 0, in particular thanks to the non-through microperforations 4 that the operculum 3 has. These tests have also highlighted a "shrink" of each portion packaged during this long period, ie a loss of water vapor having the effect of regularly reducing the weight of each portion (the average weight loss observed being of the order of 0.1% to 0.2% per week). It has thus been found that there is no droplet of water inside the package 1 and the non-swelling of the lid 3. This limited loss of water vapor advantageously results in a suppression of the usual defects sandy crust when opening the package 1 and helps to improve the taste of the portion during consumption.

Finally, it will be noted that it has been verified by these tests that the color of the crust of each portion packaged according to the invention is hardly modified after six to eight weeks thanks to the internal atmosphere provided by this package. 1. 25

Claims (14)

1) food article comprising: - at least one cut portion of a soft cheese 5 having a crust and a sliced surface free of crust exposing said paste, and - a package (1) closed enveloping said at least a portion and having at least one permselective wall (3) adapted to control oxygen and carbon dioxide volumetric contents defining an inner atmosphere of the package by gaseous exchange with the outside of the package, so that At least three weeks after cutting of said at least one portion, the crust has a maintained metabolic activity and the sliced surface is substantially free of undesirable microorganisms, characterized in that said cheese is washed rind and in that said oxygen content by volume is non-zero and less than 1% during said storage period ion. 2) Article according to claim 1, characterized in that said oxygen content is less than 0.5% and preferably less than or equal to 0.2% during said shelf life. 3) Article according to claim 1 or 2, characterized in that said volume content of carbon dioxide is between 9 and 16% during said shelf life. 4) Article according to claim 3, characterized in that said content by volume of carbon dioxide is between 12 and 14% during said shelf life. 30 5) Article according to claim 3 or 4, characterized in that said internal atmosphere has said oxygen content and carbon dioxide content during said shelf life of at least four weeks and preferably at least four weeks. six weeks. 6) Article according to one of the preceding claims, characterized in that said at least one permselective wall (3) has non-through microperforations (4) which open only to the inside of the package (1), in one face internal of said at least one wall. 7) Article according to claim 6, characterized in that said at least one permselective wall comprises (3): - at least one flexible film (3b) which is turned towards the inside or the outside of the package ( 1) and which has said microperforations (4), and - at least one porous layer (3d) imperforate, which overcomes said at least one film and which is turned towards the outside or the inside of the packaging opposite of said at least one film. 8) Article according to claim 7, characterized in that said microperforations (4) each have a larger transverse dimension between 50 pm and 1000 pm and are arranged in the form of lines (5) straight, curved or broken spaced some others. 9) Article according to claim 7 or 8, characterized in that the package (1) comprises a tray (2), for example a compact polystyrene 25, and a said permselective wall (3) which is heat-sealed on a flange (2a) of said tray by said at least one film (3b), for example polyester. 10) An article according to one of claims 7 to 9, characterized in that said at least one porous layer (3d) comprises a sheet of a cellulosic material which absorbs moisture from said at least a portion and said internal atmosphere and which is preferably paper, said at least one portion and said inner atmosphere being subject to substantially constant moisture loss during said shelf life. 11) Article according to one of claims 7 to 10, characterized in that said permselective wall (3) further comprises: - an adhesive (3c), for example of polyurethane type, interposed between said at least one porous layer ( 3d) which has a basis weight for example of between 20 and 70 g / m 2, and said at least one film (3b) which has a thickness for example of between 5 μm and 20 μm, and a sealing varnish (3a) interposed between said at least one inner film and said flange. 12) A method of preserving, for at least three weeks after cutting, at least one cut portion of a soft cheese in a package (1) controlling oxygen and carbon dioxide content in the interior of the container. packaging by gas exchange with the outside of the package, so that said at least one portion has at the end of said weeks a crust maintained metabolic activity and a sliced surface devoid of crust exposing said pulp being substantially virgin undesirable microorganisms , characterized in that said cheese is washed rind and in that said oxygen content by volume is non-zero and less than 1% during said weeks. 13) The method of conservation according to claim 12 of said at least one portion for at least six weeks after cutting, characterized in that said oxygen content by volume is less than 0.5% and preferably less than or equal to 0.2%. , and in that said content by volume of carbon dioxide is between 9 and 16% and preferably between 12 and 14%. 3033125 17 14) A method of conservation according to claim 12 or 13, characterized in that the inside of the package (1) is the seat of a loss of substantially constant humidity during said weeks after cutting resulting in a relative loss of weight for said at least one portion for example of the order of 0.1 to 0.2% per week, so that the presence of water droplets inside the package and a alteration of said crust at the end of said weeks.