WO1992014998A1 - Biological device for verifying storage at positive temperature of perishable substances, and method of manufacture - Google Patents
Biological device for verifying storage at positive temperature of perishable substances, and method of manufacture Download PDFInfo
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- WO1992014998A1 WO1992014998A1 PCT/FR1992/000168 FR9200168W WO9214998A1 WO 1992014998 A1 WO1992014998 A1 WO 1992014998A1 FR 9200168 W FR9200168 W FR 9200168W WO 9214998 A1 WO9214998 A1 WO 9214998A1
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- Prior art keywords
- melting point
- bacteria
- inoculum
- temperature
- ethyl
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K3/00—Thermometers giving results other than momentary value of temperature
- G01K3/02—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values
- G01K3/04—Thermometers giving results other than momentary value of temperature giving means values; giving integrated values in respect of time
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/06—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using melting, freezing, or softening
Definitions
- 2,329,987; 2,361,074; 2,370,269; 2,471,596; 2,553,512; 2,560,992; 2,611,042; 2,522,669 are based on the irreversible reaction of chemical substances (acetylenic compounds, for example) or biochemicals (enzymes), brought into contact at a given time of storage, or during the fusion of compounds at a determined temperature.
- chemical substances acetylenic compounds, for example
- biochemicals enzymes
- the ⁇ uel consists of a container, preferably a test tube or microtube, containing a culture medium seeded with acidifying bacteria commonly used in the food industry, the whole guaranteeing total safety.
- the demonstration of the non-conservation at the required temperature is manifested by the change in coloration of a pH indicator resulting from the appearance of an organic acid, in particular lactic acid originating from the degradation of a fermentable sugar, during the bacterial proliferation which occurs in a determined time, taking into account the normal conditions of handling of the products in question.
- strains of acidifying bacteria are used, alone or in combination, whose growth kinetics at storage temperatures is of the same order as that of the microorganisms present in the product.
- One of the main advantages of the present invention is therefore to simulate in a homothetic fashion the development of microorganisms which may be present in the product, since real parallel growth is achieved.
- Another advantage of the conservation control according to the invention lies in its simplicity of manufacture insofar as it requires only a sterilized bacteriological culture medium, one or more strains of acidifying bacteria, a medium the point of which is judiciously chosen in which the strain (s) of acidifying bacteria is (are) included, a means allowing sterilization, refrigeration and mixing of the medium with a dilution of the bacterial suspension, a means of distribution by micro-metering pump and means allowing the conditioning of said medium sown at low temperature (close to 0 ° C.) in containers made of transparent material provided with a hollow plug.
- a third advantage of the device according to the invention lies in the total harmlessness of the reagents used, which fully authorizes their use in the food industries. mental, since said medium contains only nutrients of food quality or pondered without specific toxicity.
- a fourth advantage of the device according to the invention lies in the use of acidifying bacteria, preferably selected lactic acid bacteria, used in the food industry and whose non-pathogenic nature has been widely demonstrated.
- Another advantage is linked to the presence of a natural latency time of the culture. Indeed, one of the major drawbacks of non-biological conservation witnesses lies in their low thermal inertia: as soon as the critical temperature is reached, the reaction occurs, generally according to the "all or nothing" principle, at least in the simplest processes, therefore the least reliable.
- the bacteria require a certain time of exposure to the critical temperature before reaching the exponential growth phase where the reaction becomes visible.
- the growth kinetics substantially follow the temperature variations, the durations of exposure to a given temperature are therefore integrated into the culture: they can accelerate or completely stop growth depending on the ambient temperature.
- control according to the invention therefore has an original buffering effect which reflects the cumulative variations in temperature which the preserved product may undergo, thus retaining its thermal memory.
- BBL Lactic Bacteria
- DIFCO® Lactic Bacteria
- reason of 55 g adjusted to pH 7.5-8.0 with 0.1 N NaOH, added from 10 to 200 m lg for ⁇ pre bromophenol, bromophenol blue, chlorophenol purple or any other colored indicator of pH or redox compatible with the survival of microorganisms.
- BBL medium a simpler medium containing, for example, only 5 to 20 g of nutritive substrate (tryptic casein hydrolyzate, for example) and a fermentable sugar such as glucose, lactose or any other sugar.
- the culture medium is sterilized according to a known method, at a temperature in the region of 120 ° C for a time in the region of 20 minutes.
- the device according to the invention is visible on Plate 1.
- the culture medium prepared as above is distributed sterile at a rate of 0.2 to 10 ml in a container (1) which can be a microtube or a tube tests with a capacity of 0.2 to 10 ml fitted with a hollow stopper (2).
- the tubes are then cooled to a temperature close to 0 ° C.
- the pure strain or the mixture of strains of selected acidifying bacteria capable of lowering the pH of the medium are used in the lyophilized state.
- These bacteria are chosen in particular from the group of mesophilic or thermophilic lactic acid bacteria.
- the most suitable germs are found among the genera Lactobacillus, Streptococcus and Leuconostoc, their species and their subspecies, present in raw materials and processed food products.
- the lyophilisate containing the acidifying bacteria at the rate of 10 3 to 10 9 germs per gram, finely sieved, is incorporated into an organic compound capable of melting at a temperature between +4 and + 10 ° C and compatible with the survival of microorganisms.
- glycerol esters in particular glycerol trioctanoate or tricapryline (melting point 10 ° C), glycerol triacetate or triacetin (melting point 4.1 ° C), benzyl laurate (melting point melting 8.5 ° C), butanediol (melting point 7.6 ° C) or esters of ethanol and methanol, in particular ethyl cinnamate (melting point 6.5 ° C), ethyl monoheptane dioate (melting point 10 ° C), ethyl monosuccinate (melting point 8 ° C) octadecenoate ethyl (melting point 5.8 ° C), diethyl octanedioate (melting point 5.9 ° C), diethyl decanedioate (melting point 5 ° C), methyl tridecanoate (melting point 6.5
- the bacterial strain homogenized in its fusible medium, is deposited at the rate of approximately 10 5 to 500 ⁇ l / cm 2 depending on the strain chosen, on a support intended to be fixed on the container filled with the culture medium.
- the support may for example consist of a hollow plug (2) and the container, a test tube or microtube (1). This filling, which must be carried out at a positive temperature, above the melting point of the chosen fusible compound, is followed by cooling at a temperature below the supercooling point of the same compound.
- the support can be installed on the container filled with sterile agar medium, while maintaining a head space of 1 to 10 mm between the contents of each element.
- the assembly is maintained, until use, at a temperature below the melting point of said compound.
- the device can be introduced directly into the packaging of the product to be checked or onto the packaging itself by means of any adhesive device; it can also be stored until use, by cold storage at a temperature below 0 ° C and, preferably, under the usual conditions of storage of frozen products.
- the stability of the device at positive temperature between 0 ° C. and the melting temperature of the fusible compound is at least 8 weeks without any detectable deterioration in the reliability of the device being noted.
- the indicator is fixed at a lower temperature at the fuse liquefaction point on the packaging of the product intended to be checked.
- the acidifying germs contained in the liquefied fuse come into contact with the underlying nutritive medium.
- the development of the microbial population then leads to a progressive acidification of the medium which leads to the change of the colored indicator.
- the delay in the appearance of the turn can be adjusted by adjusting the concentration of acidifying bacteria incorporated in the fuse. It also depends on the subsequent storage temperature.
- EXAMPLE 1 When the acidifying germs consist of a mixture of mesophilic lactic acid bacteria up to 10 8 bacteria per gram and if the temperature remains greater than or equal to the melting point of tricapryline (10 ° C.), the color change of the pH indicator from purplish red to yellow appears under the following conditions:
- the acidification can continue because the contact remains permanent between the inoculum and the culture medium but its kinetics are very slow and the start of the turn only appears after a fortnight.
- Example 2 When the acidifying germs consist of a mixture of mesophilic lactic acid bacteria up to 10 8 bacteria per gram and if the temperature remains above greater than or equal to the melting point of ethyl cinnamate (6.5 ° C), the change in color of the pH indicator from purplish red to yellow appears under the following conditions:
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Micro-Organisms Or Cultivation Processes Thereof (AREA)
- Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
- Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)
Abstract
A biological device for verifying storage of perishable substances at positive temperatures comprises a culture medium (4) for micro-organisms and an inoculum of living micro-organisms (3), these two elements being kept separate in a single assembly as long as the required storage conditions are maintained.
Description
CONSERVATION A TEMPERATURE POSITIVE DE SUBSTANCES POSITIVE TEMPERATURE STORAGE OF SUBSTANCES
PERISSABLES ET SON PROCEDE DE FABRICATIONPERISHABLE AND PROCESS FOR PRODUCING THE SAME
En vue d'assurer leur conservation, les denrées périssables sont entreposées à des températures voisines ou inférieures au point de congélation de l'eau, notamment pour limi¬ ter ou inhiber la croissance de microorganismes susceptibles d'affecter la qualité hygiénique de ces produits. Ce respect de la qualité repose sur une maîtrise totale de la chaîne du froid, pour lequel des témoins dits de "temps-température" ont été réalisés. Ces témoins, tels que ceux décrits dans les brevets n° 2.329.987 ; 2.361.074 ; 2.370.269 ; 2.471.596 ; 2.553.512 ; 2.560.992 ; 2.611.042 ; 2.522.669, sont basés sur la réaction irréversible de substances chimiques (composés acétyléniques, par exemple) ou biochimiques (enzymes), mises en contact à un instant donné de l'entreposage, ou lors de la fusion de composés à une température déterminée. Malgré leurs qualités, ces témoins cryogéniques ont l'inconvé¬ nient de mettre en oeuvre des substances chimiques souvent incompatibles avec les produits destinés à l'alimentation humaine ou animale. Par ailleurs, leur réalisation est souvent déli¬ cate, ce qui les rend trop coûteux pour une diffusion de grande consommation et limite con - sidérablement leur champ d'application. En outre, il est difficile de les transposer à des tem¬ pératures positives, car si aux températures de congélation l'inertie thermique des produits surgelés est grande, il n'en va pas de même aux températures positives, lorsqu'il n'existe pas de glace pour amortir pendant suffisamment longtemps l'élévation de température. C'est le cas de la majorité des produits dits "frais", qui doivent être maintenus à des tempé¬ ratures comprises entre 0°C et +10°C, notamment les produits alimentaires de "quatrième et cinquième gammes" (légumes prédécoupés et lavés, plats préparés sous vide, viandes, etc...) dans lesquels l'acidité naturelle est souvent insuffisante pour limiter la prolifération microbienne.In order to ensure their conservation, perishable foodstuffs are stored at temperatures close to or below the freezing point of water, in particular to limit or inhibit the growth of microorganisms liable to affect the hygienic quality of these products. This respect for quality is based on total control of the cold chain, for which so-called "time-temperature" witnesses have been produced. These witnesses, such as those described in patents No. 2,329,987; 2,361,074; 2,370,269; 2,471,596; 2,553,512; 2,560,992; 2,611,042; 2,522,669, are based on the irreversible reaction of chemical substances (acetylenic compounds, for example) or biochemicals (enzymes), brought into contact at a given time of storage, or during the fusion of compounds at a determined temperature. Despite their qualities, these cryogenic witnesses have the disadvantage of using chemical substances which are often incompatible with products intended for human or animal consumption. In addition, their realization is often delicate, which makes them too costly for a distribution of large consumption and considerably limits their field of application. In addition, it is difficult to transpose them to positive temperatures, because if at freezing temperatures the thermal inertia of frozen products is high, it is not the same at positive temperatures, when there is no no ice to dampen the rise in temperature for long enough. This is the case for the majority of so-called "fresh" products, which must be kept at temperatures between 0 ° C. and + 10 ° C., in particular food products of "fourth and fifth ranges" (pre-cut vegetables and washed, vacuum-prepared dishes, meats, etc.) in which the natural acidity is often insufficient to limit microbial growth.
L'invention faisant l'objet de la présente demande de brevet se propose de pallier les inconvénients décrits ci-dessus en réalisant un témoin bioloεiαue de conservation, leαuel
consiste en un contenant, de préférence un tube ou microtube à essais, renfermant un milieu de culture ensemencé en bactéries acidifiantes couramment utilisées dans l'industrie alimen¬ taire, l'ensemble garantissant une innocuité totale.The invention which is the subject of this patent application proposes to overcome the drawbacks described above by producing a biological witness for conservation, the αuel consists of a container, preferably a test tube or microtube, containing a culture medium seeded with acidifying bacteria commonly used in the food industry, the whole guaranteeing total safety.
La mise en évidence de la non-conservation à la température requise se manifeste par le changement de coloration d'un indicateur de pH résultant de l'apparition d'un acide orga¬ nique, notamment l'acide lactique provenant de la dégradation d'un sucre fermentescible, lors de la prolifération bactérienne qui se produit en un temps déterminé, tenant compte des conditions normales de manutention des produits en question.The demonstration of the non-conservation at the required temperature is manifested by the change in coloration of a pH indicator resulting from the appearance of an organic acid, in particular lactic acid originating from the degradation of a fermentable sugar, during the bacterial proliferation which occurs in a determined time, taking into account the normal conditions of handling of the products in question.
Lors de l'entreposage normal au froid des denrées périssables, donc non stériles, la croissance des microorganismes (notamment celle des bactéries), est considérablement ra¬ lentie, puisqu'elle garantit la durée de conservation des produits. Dans le dispositif selon l'invention, on utilise isolément ou en association, des souches de bactéries acidifiantes dont la cinétique de croissance aux températures d'entreposage est du même ordre que celle des microorganismes présents dans le produit.During normal cold storage of perishable products, therefore non-sterile, the growth of microorganisms (especially that of bacteria), is considerably slowed down, since it guarantees the shelf life of the products. In the device according to the invention, strains of acidifying bacteria are used, alone or in combination, whose growth kinetics at storage temperatures is of the same order as that of the microorganisms present in the product.
L'un des principaux avantages de la présente invention est donc de simuler de façon homothétique le développement des microorganismes pouvant être présents dans le produit, puisqu'on réalise une véritable croissance parallèle.One of the main advantages of the present invention is therefore to simulate in a homothetic fashion the development of microorganisms which may be present in the product, since real parallel growth is achieved.
Un autre avantage du témoin de conservation selon l'invention réside dans sa sim¬ plicité de fabrication dans la mesure où il ne nécessite qu'un milieu de culture bactériologi¬ que stérilisé, une ou plusieurs souches de bactéries acidifiantes, un milieu dont le point de fusion est judicieusement choisi dans lequel la ou les souche(s) de bactéries acidifiantes est (sont) incluse(s), un moyen permettant la stérilisation, la réfrigération et le mélange du mi¬ lieu avec une dilution de la suspension bactérienne, un moyen de distribution par micro - pompe doseuse et un moyen permettant le conditionnement dudit milieu ensemencé à basse température (voisine de 0°C) dans des contenants en matériau transparent munis d'un bou¬ chon creux.Another advantage of the conservation control according to the invention lies in its simplicity of manufacture insofar as it requires only a sterilized bacteriological culture medium, one or more strains of acidifying bacteria, a medium the point of which is judiciously chosen in which the strain (s) of acidifying bacteria is (are) included, a means allowing sterilization, refrigeration and mixing of the medium with a dilution of the bacterial suspension, a means of distribution by micro-metering pump and means allowing the conditioning of said medium sown at low temperature (close to 0 ° C.) in containers made of transparent material provided with a hollow plug.
Un troisième avantage du dispositif selon l'invention réside dans l'innocuité totale des réactifs mis en oeuvre, ce qui autorise pleinement leur utilisation dans les industries ali-
mentaires, puisque ledit milieu ne contient que des nutriments de qualité alimentaire ou ré¬ putés sans toxicité particulière.A third advantage of the device according to the invention lies in the total harmlessness of the reagents used, which fully authorizes their use in the food industries. mental, since said medium contains only nutrients of food quality or reputed without specific toxicity.
Un quatrième avantage du dispositif selon l'invention réside dans l'emploi de bacté¬ ries acidifiantes, de préférence des bactéries lactiques sélectionnées, utilisées dans l'indus¬ trie alimentaire et dont le caractère non pathogène a été largement démontré.A fourth advantage of the device according to the invention lies in the use of acidifying bacteria, preferably selected lactic acid bacteria, used in the food industry and whose non-pathogenic nature has been widely demonstrated.
Un autre avantage résulte de la grande sensibilité du test dû à la nature biologique du témoin de conservation. En effet, les microorganismes ne se développent que si les condi¬ tions sont favorables. Pour la plupart des bactéries aérobies mésophiles (non psychrotro- phes), la limite inférieure de la température de croissance est voisine de +8°C. Il y a donc une corrélation évidente entre le démarrage des souches incluses dans le témoin et la proli¬ fération de celles qui sont éventuellement présentes dans le produit mis en conservation.Another advantage results from the great sensitivity of the test due to the biological nature of the conservation control. Indeed, microorganisms only develop if the conditions are favorable. For most aerobic mesophilic bacteria (non-psychrotrophic), the lower limit of the growth temperature is around + 8 ° C. There is therefore an obvious correlation between the start of the strains included in the control and the proliferation of those which are possibly present in the product stored.
Un autre avantage est lié à la présence d'un temps de latence naturel de la culture. En effet, l'un des inconvénients majeurs des témoins de conservation non biologiques réside dans leur faible inertie thermique : dès que la température critique est atteinte, la réaction se produit, généralement selon le principe du "tout ou rien", tout au moins dans les procédés les plus simples, donc les moins fiables. Dans le dispositif selon l'invention, les bactéries exigent un certain temps d'exposition à la température critique avant d'atteindre la phase ex¬ ponentielle de croissance où la réaction devient visible. De plus, la cinétique de croissance suit sensiblement les variations de température, les durées d'exposition à une température donnée sont donc intégrées dans la culture : elles peuvent accélérer ou arrêter complètement la croissance en fonction de la température ambiante. Cette progression du développement bactérien est directement visible sur le témoin selon l'invention, du fait de la diffusion de l'acidité entre le point d'inoculation situé à la surface du milieu de culture et le fond du tube qui peut se trouver à plusieurs centimètres de la surface. Le témoin selon l'invention possè¬ de donc un effet tampon original qui reflète les variations cumulées de température que peut subir le produit conservé, conservant ainsi sa mémoire thermique.Another advantage is linked to the presence of a natural latency time of the culture. Indeed, one of the major drawbacks of non-biological conservation witnesses lies in their low thermal inertia: as soon as the critical temperature is reached, the reaction occurs, generally according to the "all or nothing" principle, at least in the simplest processes, therefore the least reliable. In the device according to the invention, the bacteria require a certain time of exposure to the critical temperature before reaching the exponential growth phase where the reaction becomes visible. In addition, the growth kinetics substantially follow the temperature variations, the durations of exposure to a given temperature are therefore integrated into the culture: they can accelerate or completely stop growth depending on the ambient temperature. This progression of bacterial development is directly visible on the control according to the invention, due to the diffusion of the acidity between the inoculation point located on the surface of the culture medium and the bottom of the tube which may be several centimeters from the surface. The control according to the invention therefore has an original buffering effect which reflects the cumulative variations in temperature which the preserved product may undergo, thus retaining its thermal memory.
Pour réaliser un témoin biologique de conservation à température positive, selon l'in¬ vention, on peut procéder de la manière suivante:
- Bouillon de culture pour Bactéries Lactiques (BBL), DIFCO® ou autre à rai¬ son de 55 g 1, ajusté à pH 7,5-8,0 par NaOH 0,1 N, additionné de 10 à 200 m lg de pour¬ pre de bromophénol, de bleu de bromophénol, de pourpre de chlorophénol ou de tout autre indicateur coloré de pH ou d'oxydo-réduction compatible avec la survie des microorganis¬ mes. On peut aussi, sans que cela affecte l'unité de l'invention, remplacer le milieu BBL par un milieu plus simple ne contenant, par exemple, que 5 à 20 g l de substrat nutritif (hy- drolysat trypsique de caséine, par exemple) et un sucre fermentescible tel que le glucose, le lactose ou tout autre sucre.utilisable et compatible avec la survie des microorganismes mis en culture, rajouté à raison de 5 à 25 g/1 de milieu. On y ajoute entre 10 et 25 g/1 d'un géli¬ fiant couramment utilisé en bactériologie tel que ragar-agar. Le milieu de culture est stérili¬ sé selon une méthode connue, à une température voisine de 120°C pendant un temps voisin 20 minutes.To produce a biological control of conservation at positive temperature, according to the invention, one can proceed as follows: - Culture broth for Lactic Bacteria (BBL), DIFCO® or other with reason of 55 g 1, adjusted to pH 7.5-8.0 with 0.1 N NaOH, added from 10 to 200 m lg for ¬ pre bromophenol, bromophenol blue, chlorophenol purple or any other colored indicator of pH or redox compatible with the survival of microorganisms. It is also possible, without affecting the unity of the invention, to replace the BBL medium with a simpler medium containing, for example, only 5 to 20 g of nutritive substrate (tryptic casein hydrolyzate, for example) and a fermentable sugar such as glucose, lactose or any other sugar. usable and compatible with the survival of the microorganisms put in culture, added in an amount of 5 to 25 g / l of medium. Between 10 and 25 g / l of a géli¬ fiant commonly used in bacteriology such as ragar-agar are added thereto. The culture medium is sterilized according to a known method, at a temperature in the region of 120 ° C for a time in the region of 20 minutes.
Le dispositif selon l'invention est visible sur la Planche 1. Le milieu de culture préparé comme ci-dessus, est distribué stérilement à raison de 0,2 à 10 ml dans un contenant (1) qui peut être un microtube ou un tube à essais d'une capacité de 0,2 à 10 ml muni d'un bouchon creux (2). Les tubes sont ensuite refroidis à une température voisine de 0°C.The device according to the invention is visible on Plate 1. The culture medium prepared as above, is distributed sterile at a rate of 0.2 to 10 ml in a container (1) which can be a microtube or a tube tests with a capacity of 0.2 to 10 ml fitted with a hollow stopper (2). The tubes are then cooled to a temperature close to 0 ° C.
Par ailleurs, la souche pure ou le mélange de souches de bactéries acidifiantes sélectionnées susceptibles d'abaisser le pH du milieu sont utilisées à l'état lyophilisé. Ces bactéries sont choisies en particulier dans le groupe des Bactéries lactiques mésophiles ou thermophiles. Les germes les mieux adaptés se rencontrent parmi les genres Lactobacillus, Streptococcus etLeuconostoc, leurs espèces et leurs sous-espèces, présents dans les ma¬ tières premières et produits alimentaires transformés. Le lyophilisât renfermant les bactéries acidifiantes à raison de 103 à 109 germes par gramme, finement tamisé, est incorporé dans un composé organique susceptible de fondre à une température comprise entre +4 et +10°C et compatible avec la survie des microorganismes. Ces composés sont choisis en particulier parmi les esters du glycerol, notamment le glycerol trioctanoate ou tricapryline (point de fu¬ sion 10°C), le glycerol triacétate ou triacétine (point de fusion 4.1°C), le laurate de benzyle (point de fusion 8.5°C), , le butanediol (point de fusion 7.6°C) ou les esters de l'éthanol et
du méthanol, notamment le cinnamate d'éthyle (point de fusion 6.5°C), le monoheptane- dioate d'éthyle (point de fusion 10°C), le monosuccinate d'éthyle (point de fusion 8°C) l'octadécènoate d'éthyle (point de fusion 5.8°C), l'octanedioate de diéthyle (point de fusion 5.9°C), le décanedioate de diéthyle (point de fusion 5°C), le tridécanoate de méthyle (point de fusion 6.5°C), le laurate de méthyle (point de fusion 5.2°C), et leur mélange de manière à fixer précisément le point de fusion. Ces subtances sont caractérisées par leur non-toxicité et leur compatibilité de proximité avec les produits destinés à l'alimentation. La poudre lyo¬ philisée est mélangée intimement avec le composé organique de façon quelconque, mais de préférence au moyen d'un homogénéiseur à ultra-sons.Furthermore, the pure strain or the mixture of strains of selected acidifying bacteria capable of lowering the pH of the medium are used in the lyophilized state. These bacteria are chosen in particular from the group of mesophilic or thermophilic lactic acid bacteria. The most suitable germs are found among the genera Lactobacillus, Streptococcus and Leuconostoc, their species and their subspecies, present in raw materials and processed food products. The lyophilisate containing the acidifying bacteria at the rate of 10 3 to 10 9 germs per gram, finely sieved, is incorporated into an organic compound capable of melting at a temperature between +4 and + 10 ° C and compatible with the survival of microorganisms. These compounds are chosen in particular from glycerol esters, in particular glycerol trioctanoate or tricapryline (melting point 10 ° C), glycerol triacetate or triacetin (melting point 4.1 ° C), benzyl laurate (melting point melting 8.5 ° C), butanediol (melting point 7.6 ° C) or esters of ethanol and methanol, in particular ethyl cinnamate (melting point 6.5 ° C), ethyl monoheptane dioate (melting point 10 ° C), ethyl monosuccinate (melting point 8 ° C) octadecenoate ethyl (melting point 5.8 ° C), diethyl octanedioate (melting point 5.9 ° C), diethyl decanedioate (melting point 5 ° C), methyl tridecanoate (melting point 6.5 ° C ), methyl laurate (melting point 5.2 ° C), and mixing them so as to precisely fix the melting point. These subtances are characterized by their non-toxicity and their proximity compatibility with products intended for food. The lyophilized powder is intimately mixed with the organic compound in any way, but preferably by means of an ultrasonic homogenizer.
La souche bactérienne, homogénéisée dans son milieu fusible, est déposée à raison d'environ 10Ô à 500 μl/cm2 selon la souche choisie, sur un support destiné à être fixé sur le contenant rempli du milieu de culture. Le support peut être, par exemple, constitué d'un bouchon creux (2) et le contenant, un tube ou microtube à essais (1). Ce remplissage qui doit s'effectuer à température positive, supérieure au point de fusion du composé fusible choisi, est suivi d'un refroissement à une température inférieure au point de surfusion du même composé. Quand le milieu est solidifié, le support peut être installé sur le contenant rempli du milieu gélose stérile, tout en maintenant un espace de tête de 1 à 10 mm entre les contenus de chaque élément.The bacterial strain, homogenized in its fusible medium, is deposited at the rate of approximately 10 5 to 500 μl / cm 2 depending on the strain chosen, on a support intended to be fixed on the container filled with the culture medium. The support may for example consist of a hollow plug (2) and the container, a test tube or microtube (1). This filling, which must be carried out at a positive temperature, above the melting point of the chosen fusible compound, is followed by cooling at a temperature below the supercooling point of the same compound. When the medium is solidified, the support can be installed on the container filled with sterile agar medium, while maintaining a head space of 1 to 10 mm between the contents of each element.
L'ensemble est maintenu, jusqu'à utilisation, à une température inférieure au point de fusion dudit composé.The assembly is maintained, until use, at a temperature below the melting point of said compound.
Le dispositif peut être introduit directement dans l'emballage du produit à contrôler ou sur l'emballage même au moyen d'un dispositif adhésif quelconque ; il peut également être stocké jusqu'à utilisation, par conservation au froid à une température inférieure à 0°C et, de préférence, dans les conditions habituelles de stockage des produits congelés. La stabili¬ té du dispositif à température positive comprise entre 0°C et la température de fusion du composé fusible est d'au moins 8 semaines sans qu'il soit noté d'altération décelable de la fiabilité du dispositif.The device can be introduced directly into the packaging of the product to be checked or onto the packaging itself by means of any adhesive device; it can also be stored until use, by cold storage at a temperature below 0 ° C and, preferably, under the usual conditions of storage of frozen products. The stability of the device at positive temperature between 0 ° C. and the melting temperature of the fusible compound is at least 8 weeks without any detectable deterioration in the reliability of the device being noted.
Lors de la mise en oeuvre du dispositif, le témoin est fixé à une température inférieure
au point de liquéfaction du fusible sur l'emballage du produit destiné à être contrôlé.During the implementation of the device, the indicator is fixed at a lower temperature at the fuse liquefaction point on the packaging of the product intended to be checked.
En cas d'élévation anormale de la température au delà de la température critique de chan¬ gement d'état du fusible, les germes acidifiants contenus dans le fusible liquéfié entrent en contact avec le milieu nutritif sous-jacent. Le développement de la population microbienne entraîne alors une acidification progressive du milieu qui conduit au virage de l'indicateur coloré. Le délai d'apparition du virage peut être réglé en ajustant la concentration en germes acidifiants incorporés dans le fusible. Il dépend également de la température ultérieure de conservation.In the event of an abnormal rise in temperature beyond the critical temperature for changing the state of the fuse, the acidifying germs contained in the liquefied fuse come into contact with the underlying nutritive medium. The development of the microbial population then leads to a progressive acidification of the medium which leads to the change of the colored indicator. The delay in the appearance of the turn can be adjusted by adjusting the concentration of acidifying bacteria incorporated in the fuse. It also depends on the subsequent storage temperature.
Exemple 1 : Lorsque les germes acidifiants sont constitués d'un mélange de bactéries lactiques mésophiles à hauteur de 108 bactéries par gramme et si la température reste supé¬ rieure ou égale au point de fusion de la tricapryline (10°C), l'évolution de la couleur de l'in¬ dicateur de pH du rouge violacé au jaune apparaît dans les conditions suivantes :EXAMPLE 1 When the acidifying germs consist of a mixture of mesophilic lactic acid bacteria up to 10 8 bacteria per gram and if the temperature remains greater than or equal to the melting point of tricapryline (10 ° C.), the color change of the pH indicator from purplish red to yellow appears under the following conditions:
Si, après fusion, le produit est ramené à une température inférieure à +7°C, l'acidificati peut se poursuivre car le contact demeure permanent entre l'inoculum et le milieu de cultur mais sa cinétique est très lente et le début de virage n'apparaît qu'au delà d'une quinzaine jours.If, after fusion, the product is brought to a temperature below + 7 ° C, the acidification can continue because the contact remains permanent between the inoculum and the culture medium but its kinetics are very slow and the start of the turn only appears after a fortnight.
Exemple 2 : Lorsque les germes acidifiants sont constitués d'un mélange de bactéries lactiques mésophiles à hauteur de 108 bactéries par gramme et si la température reste supé-
rieure ou égale au point de fusion du cinnamate d'éthyle (6.5°C), l'évolution de la couleu de l'indicateur de pH du rouge violacé au jaune apparaît dans les conditions suivantes :Example 2: When the acidifying germs consist of a mixture of mesophilic lactic acid bacteria up to 10 8 bacteria per gram and if the temperature remains above greater than or equal to the melting point of ethyl cinnamate (6.5 ° C), the change in color of the pH indicator from purplish red to yellow appears under the following conditions:
Claims
REVENDICATIONS
1) Dispositif biologique de contrôle de la conservation de substances périssables maintenue à température positive, caractérisé en ce qu'il est constitué d'un milieu de culture pour mi croorganismes et d'un inoculum de microorganismes vivants, les deux éléments étant mainte nus séparés dans un ensemble unique tant que les conditions requises de conservation son maintenues.1) Biological device for controlling the conservation of perishable substances maintained at a positive temperature, characterized in that it consists of a culture medium for mid-organisms and an inoculum of living micro-organisms, the two elements being kept separate in a single set as long as the required storage conditions are maintained.
2) Dispositif selon la revendication 1, caractérisé en ce que l'inoculum de microorganisme vivants est constitué de bactéries acidifiantes, susceptibles de dégrader les sucres fermentesci- bies en acides organiques, associé à un composé fusible aux températures comprises entre -- - et - lO°C, compatible avec la survie desdites bactéries.2) Device according to claim 1, characterized in that the inoculum of living microorganisms consists of acidifying bacteria, capable of degrading the fermentable sugars into organic acids, associated with a meltable compound at temperatures between - - and - 10 ° C, compatible with the survival of said bacteria.
3) Dispositif selon les revendications 1 et 2, caractérisé en ce que les bactéries acidifiantes présentes dans l'inoculum sont choisies dans le groupe des Bactéries Lactiques mésophiies e: thermophiles et, notamment, dans les genres Lactobacillus, Streptococcus et Leuconoswc. leurs espèces et leurs sous-espèces.3) Device according to claims 1 and 2, characterized in that the acidifying bacteria present in the inoculum are chosen from the group of Lactic Bacteria mesophiies e: thermophilic and, in particular, in the genera Lactobacillus, Streptococcus and Leuconoswc. their species and their subspecies.
4) Inoculum selon 1, 2 et 3, caractérisé en ce que les bactéries acidifiantes sélectionnées sont utilisées à l'état lyophilisé, en souches pures ou en mélange, à raison d'une concentration fina¬ le dans le composé fusible comprise entre 10-^ et 109 germes par gramme.4) Inoculum according to 1, 2 and 3, characterized in that the selected acidifying bacteria are used in the lyophilized state, in pure strains or in mixture, at the rate of a fina¬ concentration in the fusible compound of between 10- ^ and 10 9 seeds per gram.
5) Inoculum selon 1, 2, 3, 4, caractérisé en ce que le composé fusible contenant les bactéries est choisi parmi des substances ne présentant pas de toxicité reconnue pour les bactéries lacti¬ ques utilisées ainsi que pour l'homme, notamment le glycerol trioctanoate ou tricapryline (point de fusion 10°C), le glycerol triacétate ou triacétine (point de fusion 4.1°C), le laurate de benzyle (point de fusion 8.5°C), , le butanediol (point de fusion 7.6°C) ou les esters de l'étha¬ nol et du méthanol, notamment le cinnamate d'éthyle (point de fusion 6.5°C), le monoheptane-
dioate d'éthyle (point de fusion 10°C), le monosuccinate d'éthyle (point de fusion 8CC) l'o décènoate d'éthyle (point de fusion 5.8°C), l'octanedioate de diéthyle (point de fusion 5.9° le décanedioate de diéthyle (point de fusion 5°C), le tridécanoate de méthyle (point de fus 6.5°C), le laurate de méthyle (point de fusion 5.2°C), et leur mélange de manière à fixer pr sément le point de fusion.5) Inoculum according to 1, 2, 3, 4, characterized in that the fusible compound containing the bacteria is chosen from substances having no recognized toxicity for the lactic bacteria used as well as for humans, in particular glycerol trioctanoate or tricapryline (melting point 10 ° C), glycerol triacetate or triacetin (melting point 4.1 ° C), benzyl laurate (melting point 8.5 ° C),, butanediol (melting point 7.6 ° C) or the esters of ethanol and methanol, in particular ethyl cinnamate (melting point 6.5 ° C), monoheptane- ethyl dioate (melting point 10 ° C), ethyl monosuccinate (melting point 8 C C) ethyl decenoate o (melting point 5.8 ° C), diethyl octanedioate (melting point melting 5.9 ° diethyl decanedioate (melting point 5 ° C), methyl tridecanoate (melting point 6.5 ° C), methyl laurate (melting point 5.2 ° C), and their mixture so as to fix pr the melting point.
6) Inoculum selon 1, 2, 3, 4, 5, caractérisé en ce que sa mise en oeuvre se fait à l'état fo du composé fusible, suivie d'un refroidissement à une température inférieure à la températ de surfusion dudit composé.6) Inoculum according to 1, 2, 3, 4, 5, characterized in that its implementation is carried out in the fo state of the fusible compound, followed by cooling to a temperature below the supercooling temperature of said compound.
7) Inoculum selon 6, caractérisé en ce que sa mise en oeuvre se fait à raison d'un volume 100 à 500 μl/cm2 et contenant de 103 à 109 germes lyophilisés par gramme de mélange fu ble.7) Inoculum according to 6, characterized in that its implementation is carried out at the rate of a volume 100 to 500 μl / cm 2 and containing from 10 3 to 10 9 freeze-dried germs per gram of fuse mixture.
8) Dispositif selon les revendications 1 à 7, caractérisé en ce que l'acidification du milieu culture sous-jacent est conditionnée par la liquéfaction préalable du fusible contenant l'ino lum bactérien et entraîne la modification progressive de couleur d'un indicateur coloré de p8) Device according to claims 1 to 7, characterized in that the acidification of the underlying culture medium is conditioned by the prior liquefaction of the fuse containing the bacterial inolum and causes the gradual change in color of a colored indicator of p
9) Dispositif selon les revendications 1 à 8, appliqué en insertion à l'emballage, permett de contrôler la conservation à température positive de produits périssables tels que les matièr premières alimentaires et leurs produits de transfoimation d'origine animale, végétale et micr bienne, ainsi que les produits pharmaceutiques, réactifs de laboratoire et produits de la phot graphie.
9) Device according to claims 1 to 8, applied as an insert to the packaging, makes it possible to control the conservation at positive temperature of perishable products such as raw food materials and their transfoimation products of animal, plant and microbial origin, as well as pharmaceuticals, laboratory reagents and photographic products.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR91/02381 | 1991-02-25 | ||
| FR9102381A FR2673287B1 (en) | 1991-02-25 | 1991-02-25 | BIOLOGICAL DEVICE FOR CONTROLLING POSITIVE TEMPERATURE STORAGE OF PERISHABLE SUBSTANCES AND MANUFACTURING METHOD THEREOF. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1992014998A1 true WO1992014998A1 (en) | 1992-09-03 |
Family
ID=9410183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FR1992/000168 WO1992014998A1 (en) | 1991-02-25 | 1992-02-25 | Biological device for verifying storage at positive temperature of perishable substances, and method of manufacture |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU1468292A (en) |
| FR (1) | FR2673287B1 (en) |
| WO (1) | WO1992014998A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000047964A1 (en) * | 1999-02-10 | 2000-08-17 | Temp-Tell Limited | Thermal history indicators |
| WO2005026383A1 (en) * | 2003-09-17 | 2005-03-24 | Cryolog S.A. | Method and device for determining if a product is in condition for use or consumption |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2671028A (en) * | 1949-10-17 | 1954-03-02 | James D A Clark | Method and means for indicating product deterioration |
| US3751382A (en) * | 1969-03-13 | 1973-08-07 | Food Control | Enzymatic indicator and method of making it |
| US3977945A (en) * | 1974-02-21 | 1976-08-31 | Food Control Ab | Time and temperature-dependent enzymatic indicator |
| US4826762A (en) * | 1987-10-23 | 1989-05-02 | Massachusetts Industry Of Technology | Enzymatic temperature change indicator |
-
1991
- 1991-02-25 FR FR9102381A patent/FR2673287B1/en not_active Expired - Fee Related
-
1992
- 1992-02-24 AU AU14682/92A patent/AU1468292A/en not_active Abandoned
- 1992-02-25 WO PCT/FR1992/000168 patent/WO1992014998A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2671028A (en) * | 1949-10-17 | 1954-03-02 | James D A Clark | Method and means for indicating product deterioration |
| US3751382A (en) * | 1969-03-13 | 1973-08-07 | Food Control | Enzymatic indicator and method of making it |
| US3977945A (en) * | 1974-02-21 | 1976-08-31 | Food Control Ab | Time and temperature-dependent enzymatic indicator |
| US4826762A (en) * | 1987-10-23 | 1989-05-02 | Massachusetts Industry Of Technology | Enzymatic temperature change indicator |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000047964A1 (en) * | 1999-02-10 | 2000-08-17 | Temp-Tell Limited | Thermal history indicators |
| US7036452B1 (en) | 1999-02-10 | 2006-05-02 | Temp-Tell Limited | Thermal history indicators |
| WO2005026383A1 (en) * | 2003-09-17 | 2005-03-24 | Cryolog S.A. | Method and device for determining if a product is in condition for use or consumption |
| AU2004272770B2 (en) * | 2003-09-17 | 2009-07-16 | Cryolog S.A. | Method and device for determining if a product is in condition for use or consumption |
| US7960176B2 (en) | 2003-09-17 | 2011-06-14 | Cryolog Sa | Method and device for determining if a product is in condition for use or consumption |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2673287A1 (en) | 1992-08-28 |
| FR2673287B1 (en) | 1994-02-11 |
| AU1468292A (en) | 1992-09-15 |
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