WO2021224579A1

WO2021224579A1 - Biopreserving packaging

Info

Publication number: WO2021224579A1
Application number: PCT/FR2021/050779
Authority: WO
Inventors: Philippe Daniel; Jean-François PILARD; Ngoc Thanh Xuan NGUYEN; Françoise LEROI; Frédérique GIGOUT; Ronan CARIOU
Original assignee: Oniris Nantes (École Nationale Vétérinaire, Agroalimentaire Et De L'alimentation De Nantes); Cnrs - Centre National De La Recherche Scientifique; Ifremer; Université du Mans
Priority date: 2020-05-06
Filing date: 2021-05-06
Publication date: 2021-11-11
Also published as: FR3109930A1; FR3109930B1

Abstract

Biopreserving packaging comprising at least one biopreserving surface intended to be in contact with at least one product to be preserved, it being possible for said product to belong to the agrifood or medical sector. This biopreserving surface further comprises a solid surface comprising at least one strain of bioprotective bacteria, such as Carnobacterium divergens.

Description

DESCRIPTION

TITLE OF THE INVENTION: BIOPRESERVING PACKAGING

The field of the present invention relates to the packaging of products or objects, preferably the packaging of the biopreservant type. The invention finds applications in particular in the food industry and in the medical, or even surgical, field. More specifically, the invention relates to a biopreservant packaging for food products and / or other products subject to contamination during their conservation, a method of preparation and G use of such a biopreservative packaging.

[0002] Several methods of conservation for the agri-food sector, also applicable to the medical sector, are known from the prior art. Indeed, the quality and shelf life of products or objects are major concerns in the field of public health and for the economic development of industrialists in the agrifood and medical sectors.

These known methods are generally based on the application of different treatments to eliminate microorganisms and / or prevent their development in food products during their storage. However, they have drawbacks.

[0004] For example, conventional heat treatment techniques induce an organoleptic and often aesthetic denaturation which may be unacceptable for many types of products. In addition, the cold preservation method, for example at 4 degrees Celsius, is not sufficient and reliable for manufacturers because the respect of the cold chain between the packaging of the food product and storage at the end consumer. is not systematically followed.

[0005] Furthermore, the techniques consisting in adding chemical, antibiotic or other additives, even authorized, are often poorly perceived by the end consumer. The food industry is therefore trying to limit their uses. [0006] And finally a modern alternative technique, better perceived by the end consumer, is called biopreservation, it proposes to apply natural compounds to products to be preserved in order to improve their preservation. However, this latter technique has several drawbacks, in particular of superhumidifying the products because of the existing modes of application which are carried out by bathing or by spraying liquid, and it requires manufacturers to carry out an additional preparation step thus making the protocol more complex. production and / or packaging of the products concerned.

[0007] From this situation, one of the aims of the invention is to provide a new solution for the preservation of food or other products intended to be preserved, making it possible to prevent the development of pathogens harmful to humans. or altering bacteria using bioprotective bacterial strains, thus overcoming the drawbacks encountered in the prior art. The shelf life is also improved and the shelf life of the products is therefore significantly improved, having a positive economic impact on the manufacturers and consumers concerned and without modifying the protocol used by the industrial producer.

[0008] To achieve this or other goals, the invention provides a biopreservant package comprising at least one biopreservative surface intended to be in contact with at least one product to be preserved. This biopreservative surface comprises a solid surface comprising at least one strain of bioprotective bacteria specific for the preservation of products. This product can equally well belong to the agri-food sector or to the medical sector.

[0009] According to the embodiment, the strain of bioprotective bacteria is fixed by adsorption and / or functionalization to the solid surface. In this way, the strain of bacteria adheres to and / or becomes incorporated into the solid surface to form the biopreservative surface.

Advantageously, the modified solid surface is hydrophilic thus contributing to the good adhesion and / or the incorporation of the strain of bacteria to the solid surface, in a homogeneous and durable manner. Thus the biopreserving surface is more stable and efficient for the conservation of products over time. The character hydrophilic is checked by measuring contact angles, before and after treatment.

The strain of bioprotective bacteria is chosen from: Carnobacterium maltaromaticum CNCM 1-4027 or called VI, Carnobacterium maltaromaticum CNCM 1-4028 or called V41, Carnobacterium maltaromaticum CNCM 1-4029 or called SF668, Lactococcus piscium CNCM 1-4031 or called EU2241, and Lactobacillus sakei CNCM 1-4704 or referred to as LHIS2885. These strains are effective in inhibiting the growth of pathogens for humans or altering the product to be preserved, in particular for seafood.

[0012] For example, the strain of bioprotective bacteria Carnobacterium divergeas V41 is applied by spraying on a solid surface intended to be in contact with a food product, thus making it possible to inhibit the growth of Listeria monocytogenes in the food product.

For the jammed products intended to be packaged according to the invention, strains of bioprotective bacteria specific for the latter may be chosen, for example, against pathogens such as the genus Salmonella, specific bioprotective bacteria will be chosen. It will be understood that to protect objects or the like in the medical field, other strains of bioprotective bacteria will also be chosen specifically.

Advantageously, the solid surface is made from a material of polymer type, preferably of biopolymer type. More preferably, the material is chosen from: polystyrene, polyethylene, polypropylene or cellulose.

[0015] Depending on the embodiment, the packaging preferably forms an interlayer and / or a covering film and / or a container, such as a tray, and / or a solid support.

[0016] The invention further relates to a method for preparing a biopreservant packaging as described above, the method comprising the following steps:

- A step of soaking the solid surface in a suspension having at least one strain of bioprotective bacteria for preferably 1 hour to 10 hours, more preferably 3 hours; a step of drying the solid surface comprising the strain of bioprotective bacteria forming the biopreserving surface using an extractor hood, for preferably a maximum of 24 hours, more preferably for between 18 and 24 hours.

Advantageously, the method comprises an additional preparation step consisting of a step of plasma treatment with argon, or nitrogen, or mixed argon and nitrogen, of the solid surface, preceding the soaking step. This step transforms the hydrophobic nature of the solid surface into a hydrophilic nature, thereby ensuring better distribution and homogeneity of the strain of bacteria over the entire solid surface.

Following this step of treatment by plasma treatment, a possible variant embodiment may consist in adding an additional step of treatment of the solid surface, in particular by carrying out a functional method! surface s ation by chemical treatment.

The invention also relates to a composition of a suspension as described above comprising at least one strain of bioprotective bacteria used to produce the biopreservant packaging. This composition may for example comprise 10 ⁹ CFU / ml of bioprotective bacteria in a nutrient medium which for example for Carnodivergens V41 is Elliker medium.

[0020] And finally the invention relates to the use of the biopreservant packaging as described for packaging food products, preferably seafood products, more preferably cured food products.

In particular, seafood constitutes an important source of consumption of animal proteins in the world and therefore the prevention and control of dangers for this type of product are of major interest in the field of public health. and for industrial economic developments.

The invention described in this document provides a biopreservative packaging incorporating bioprotective bacteria which ensures a longer shelf life for the packaged product while preventing the development of pathogens, in particular of the Listeria monocytogenic species in the case of seafood. Other characteristics and advantages of the invention will become apparent on reading the detailed description below, this description referring to the appended figures among which:

[0024] [Fig. 1] is a set of scanning electron microscopy (SEM) photos at x500, x100 and x5000 magnifications comparing in two samples the distribution of Carnobacterium divergens bacteria on a solid surface thus forming a biopreservative surface according to the invention. The first sample a) not having undergone any preliminary treatment according to a first embodiment and the second sample b) having undergone a preliminary treatment of the solid surface by plasma treatment of argon and nitrogen, according to a second embodiment.

[0025] [Fig. 2] is a graph showing the growth of Listeria monocytogenes (in CFU / g) at 8 degrees Celsius for 14 days, A) in the absence of a solid surface, B) with an untreated solid surface, C) with a untreated solid surface on which is attached at least one strain of Carnobacterium forming a biopreserving surface according to a first embodiment of the invention, D) with a solid surface treated with the argon + nitrogen plasma treatment and E) with a treated solid surface to the argon + nitrogen plasma treatment to which is attached at least one strain of Carnobacterium, forming a biopreserving surface according to a second embodiment of the invention.

[0026] [Fig. 3] is a graph showing the growth of Listeria monocytogenes at 4 degrees Celsius for the first week, then at 8 degrees Celsius for the next 3 weeks. 1) in a food product, such as control smoked salmon inoculated with Listeria monocytogenes, 2) in a smoked salmon inoculated with Listeria monocytogens placed on a biopreservant packaging according to one embodiment of the invention, 3) in a smoked salmon inoculated with Listeria monocytogens on which a bacterial strain of Carnobacterium is sprayed, and 4) has the contamination threshold tolerated by the EFSA (European Food Safety Authority - 2018) for ready-to-eat foods that may allow the development of Listeria monocytogenes.

The present invention will be better understood on reading a following exemplary embodiment, which illustrates the invention without limitation. [0028] A novel biopreservant package according to the invention is a package using mild preservation technology to improve the safety and / or shelf life of a product by using protective microorganisms to prevent the development of unwanted germs. In practice, this packaging can consist of an insert, a film, or a container intended to participate in the packaging of the product to be preserved. According to a main embodiment, the packaging has at least part of the materials which are easy to use in the packaging sector. For example, polystyrene or polypropylene which are widely used as materials in contact with food.

[0029] According to the invention, the main feature of the biopreservant packaging is that it comprises at least one surface exhibiting the preservation technology which is in contact with the product. This surface is called the biopreservative surface. More specifically, this biopreservative surface comprises a solid surface coated with at least one strain of bioprotective bacteria.

According to a first embodiment, the solid surface does not undergo any prior treatment and is directly contacted with bioprotective bacteria. The solid surface is then hydrophobic or hydrophilic in nature.

According to a second embodiment, the solid surface undergoes a preparatory treatment comprising a plasma treatment, one of the objectives of which is to change the hydrophobic nature of the solid surface to hydrophilic nature. The gases used are Oxygen alone or Argon alone or Nitrogen alone or Argon and Nitrogen combined. As an example of a possible protocol, the plasma treatment conditions are as follows: Argon with volumetric flow rate of 10 sccm (standard cubic centimeters per minute), scanning for 3 minutes at 0 Watt, then treatment for 5 minutes at 200 Watts then nitrogen scanning, 10 sccm, 3 minutes at 0 Watt and 5 minutes treatment at 200 Watts.

This treatment step during the preparation process of the invention has the advantage, inter alia, of promoting better homogeneity of the strain of bacteria on the solid surface by modifying the surface property from hydrophobic to hydrophilic. Indeed, using a scanning electron microscope one can observe a better distribution and fixation of bacteria on the solid surface, as illustrated in Figure 1 at different magnifications, respectively from left to right: x500, x100 and x5000, the upper thumbnails being a sample, according to the first embodiment, of which the solid surface has not undergone any treatment and the lower thumbnails being a sample, according to the second embodiment, of which the solid surface has not undergone any treatment. solid surface has undergone an Argon + Nitrogen plasma treatment. Thus, it will be noted that the biopreservant surface treated beforehand to be hydrophilic is more homogeneous and uniform. The effectiveness of the bioprotective bacteria is therefore improved due to a better distribution of the latter on the solid surface. As illustrated in figure 2, representing the growth of bacteria type Listeria monocytogenes in A) a conventional medium without particular solid surface, on B) a solid surface, interlayer type, untreated, on C) an interlayer without prior treatment and exhibiting the bacterial strain of the genus Carnobacterium, on D) a previously treated interlayer and on E) a treated interlayer and exhibiting the bacterial strain of the genus Carnobacterium. This FIG. 2 clearly illustrates the remarkable effectiveness of the inhibition of the growth of Listeria monocytogenes according to the invention, that is to say when an interlayer is brought into contact with the bacterial strain of the genus Carnobacterium, according to the method of embodiment C) or E) the interlayer is respectively untreated and treated.

Following this step of treatment by plasma treatment, a possible variant embodiment may consist in adding an additional step of treatment of the solid surface, in particular by carrying out a surface functionalization by chemical treatment.

For example, one possible functionalization method is bromination by suitable plasma, which makes it possible to generate bromine functions on the solid surface, for example on polypropylene (PP). The C-Br functionalities created on the surface of polypropylene are very reactive for the grafting of molecules. After bromination of the Bromine functionalized solid surface (PP-Br), the latter is rinsed with tetrahydrofuran (THF) to remove unreactive bromine particles and other molecules of low mass. The functional group of primary interest in fixing as a result of bromination of the surface of polypropylene is a primary amine. For this, a solution of polyglycerol (PG) functionalized amine (PG-NH2) was prepared. This solution is itself dissolved in methanol (MeOH). The PP-Br solid surface, rinsed beforehand with methanol, is introduced into the solution of PG — NH2 + MEOH then rinsed and dried. This functionalization step will ensure covalent attachment of bioprotective bacteria to the solid surface and therefore better fixation and duration over time. This described treatment method is in no way limiting, in fact other chemical functionalization methods are possible with the same objective of covalent attachment.

During the process for preparing the biopreservant packaging according to the invention, the solid surface according to the first and the second embodiment, undergoes a step of bringing into contact with at least one strain of bioprotective bacteria, for example: Carnobacterium. This contacting is interesting in that a physical phenomenon of fixation takes place between the bacteria and the solid surface. This phenomenon provides binding of bacteria to the solid surface, advantageously more durable, making the biopreservative packaging durable and therefore more stable over time. Several variants of the fixation phenomenon (adsorption, functionalization, chemical treatment, etc.) are also possible, the goal here resides in that the bacteria are intimately linked to the solid surface, and that the solid surface is homogeneously covered with bacteria to have an effective biopreservative surface.

To do this, the contact can be made by soaking the solid surface in a suspension comprising at least one bacterial strain of the type: Lactococcus piscium CNCM 1-4031, Carnobacterium divergeas V41.

This technique of contacting by dipping is an exemplary embodiment which should not be considered as limiting. Another variant embodiment may consist of bringing the strain of bioprotective bacteria into contact using a technique involving lyophilization.

After having produced a biopreserving surface, in other words, when the solid surface comprises bioprotective bacteria, it is essential to proceed to the drying step consisting in sterilizing the solid surfaces under an extractor hood, preferably up to 24 hours, more preferably from 18 to 20 hours.

Figure 3 is a graph showing the growth of Listeria monocytogenes at 4 degrees Celsius for the first week, then at 8 degrees Celcius for the next 3 weeks. 1) in a food product, such as control smoked salmon inoculated with Listeria monocytogenes, 2) in a smoked salmon inoculated with Listeria monocytogenes placed on a biopreservant packaging according to one embodiment of the invention, 3) in a smoked salmon inoculated with Listeria monocytogenes on which a bacterial strain of Carnobacterium is sprayed, and 4) exhibits the contamination threshold tolerated by EFSA (2018) for ready-to-eat foods that may allow the development of Listeria monocytogenes.

[0041] These results confirm that the invention 2) has the effect of inhibiting the growth of targeted bacteria and thus of increasing the shelf life, for example, of a seafood type food product.

Indeed, the presence of the biopreserving surface, comprising bioprotective bacteria attached to the solid surface, in contact with the product to be preserved offers a longer shelf life compared to a product on which has been sprayed with bioprotective bacteria. . The concentration of Listeria monocytogenes remains until the use-by date below 102 CFU / g, the threshold tolerated by EFSA.

The preceding description clearly explains how the invention makes it possible to achieve the objectives that it has set itself and in particular to propose a new biopreservative packaging which simultaneously makes it possible to promote compliance with tolerance thresholds with respect to -vis of contamination with Listeria monocytogenes of the packaged product and to respect the esthetic aspect of the product. It is understood that the use of this biopreservative packaging limits the humidification of the product compared to the conventional spraying or soaking method. Furthermore, it will be noted that the treated solid supports can be stored for a long time until their use. In addition, these treated solid supports are ready to use and therefore saves the implementation of additional so-called conservation to be done on food products before packaging these products for the industrial.

[0044] The biopreservative packaging according to the invention therefore represents the only means known to date for lasting preservation of products without modifying or altering the composition and / or the aesthetic appearance of the product.

The embodiments which have been described in detail above are not limiting of the invention. In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically operative combination of these means.

Claims

[Claim 1] Biopreservant packaging comprising at least one biopreservant surface intended to be in contact with at least one product to be preserved, characterized in that said biopreservant surface comprises a solid surface comprising at least one strain of bioprotective bacteria chosen from: Carnobacterium maltaromaticum CNCM 1-4027, Carnobacterium maltaromaticum CNCM 1-4028, Carnobacterium maltaromaticum CNCM 1-4029, Lactococcus piscium CNCM 1-4031, and Lactobacillus sakei CNCM 1-4704.

[Claim 2] Packaging according to the preceding claim, characterized in that said strain of bioprotective bacteria is fixed by adsorption and / or functionalization by chemical treatment of the solid surface.

[Claim 3] A package according to any one of the preceding claims, characterized in that the solid surface is hydrophilic.

[Claim 4] Packaging according to any one of the preceding claims, characterized in that the solid surface is made from a material of the polymer type, preferably of the biopolymer type.

[Claim 5] A method of preparing a biopreservant package according to any one of the preceding claims, the method comprising:

- A step of soaking the solid surface in a suspension exhibiting at least one strain of bioprotective bacteria chosen from: Carnobacterium maltaromaticum CNCM 1-4027, Carnobacterium maltaromaticum CNCM 1-4028, Carnobacterium maltaromaticum CNCM 1-4029, Lactococcus piscium CNCM 1-4031 , and Lactobacillus sakei CNCM 1-4704, preferably lasting 1 h to 10 h, more preferably 3 h;

- a step of sterile drying of the solid surface comprising the strain of bioprotective bacteria forming the biopreserving surface using an extractor hood, preferably for a maximum of 24 hours, more preferably between 18 and 24 hours.

[Claim 6] A method according to the preceding claim, according to which a step of plasma treatment with argon and / or nitrogen of the solid surface, precedes the soaking step.

[Claim 7] Composition of a suspension comprising at least one strain of bioprotective bacteria chosen from: Carnobacterium maltaromaticum CNCM 1-4027, Carnobacterium maltaromaticum CNCM 1-4028, Carnobacterium maltaromaticum CNCM 1-4029, Lactococcus piscium CNCM 1-4031, and Lactobacillus sakei CNCM 1-4704 and used to produce the biopreservant packaging according to any one of claims 1 to 4, characterized in that it comprises 10 ⁹ CFU / ml of bioprotective bacteria in nutrient medium.

[Claim 8] Use of the biopreservant packaging according to any one of claims 1 to 4 for packaging food products, preferably seafood, more preferably cured food products.