BACTERIA-TRAPPING ITEM

Technical Field

The present invention relates to a bacteria-trapping item, to the manufacturing process thereof and to possible further uses thereof, wherein the bacteria- trapping item is preferably a non-woven fabric containing at least one polymeric cationic agent having a non-biocidal immobilizing effect on bacteria.

Background Art

In the present description and following claims, the term "biocidal product" shall be understood to have the meaning given by European Regulation no. 528/2012 which specifies that a biocidal product comprises “...any substance or mixture, in the form in which it is supplied to the user, consisting of, containing or generating one or more active substances, with the intention of destroying, deterring, rendering harmless, preventing the action of, or otherwise exerting a controlling effect on any harmful organism by any means other than mere physical or mechanical action”. By analogy, the term “non-biocidal product” should therefore be understood as a substance, preferably a chemical, non- biological and non-destructive substance that exerts a physical or mechanical action. In this context, the non-biocidal action of the polymeric cationic agent of the invention may be reversible, i.e. the bacteria once trapped may also be released according to known techniques.

Nonwovens are used in a great many areas.

One of these is, for example, their use inside the drum of washing machines during the washing of clothes to prevent the migration of a certain amount of dyes from more colored garments and the subsequent absorption of the same on garments with lighter, or different, colors. These non-woven fabrics are commercially known as “color catchers” and use different technologies to solve the above-mentioned problems.

The use of sequestering agents such as surfactants to aid the dispersion of dyes in washing water is well known. In such applications, the aim is to inhibit the transfer of dyes from one garment to another and thus prevent the transport of colors through the washing water. The use of cationic polymers as sequestering agents for dyes is also widely known. Such polymers are generally chemically or physically bonded to the fabric substrate to capture colors so as to allow high stability of anchoring of colors on the substrate.

Other equally widespread applications of nonwovens are, for example, in the personal-care sector or in domestic and/or industrial cleaning in the form of dust-capture cloths, mite-capture cloths, etc.

The Applicant, already active in the production of color-catching products, realized that by introducing a number of modifications to the manufacturing process of the color-catching nonwoven fabric, the latter was surprisingly well suited for use as a bacterial trap also in sectors other than washing.

Various laboratory tests were carried out to verify the effectiveness of the new solution in particular in the food packaging sector and as an odor trap (e.g. used in absorbing articles or shoe insoles), the results of which, as will be seen later in this disclosure, showed evident results. For example, an increase in the shelf life of certain food products has been demonstrated, especially in the case of meat stored in food trays, as well as an excellent increase in anti-odor power.

Most of the problems associated with meat preservation and the production of unpleasant odors are due to bacterial proliferation, the growth of which is favored in the presence of fluids/liquids. As specified, for example, in publication no. 10.1093/femsle/fnvl l l dal titolo “Identification of axillary Staphylococcus sp. involved in the production of the malodorous thioalcohol 3- methyl-3-sufanylhexan-l-ol”, secretions metabolized by bacteria play a key role in the production of unpleasant odors.

In the food sector, various solutions are known to absorb or otherwise drain excess fluids released from meat by the insertion of absorbing “pads” coupled to the bottom of the container.

Diversely, in the sector of odor-capturing articles, dress shields are known, such as the one described, for example, in Italian utility model patent no. 236728, wherein the solution consists in simply absorbing perspiration without, however, solving the problems related to odor. In the above solutions, bacterial proliferation in the presence of smaller quantities of liquids is therefore only partially mitigated.

Description of the Invention

The Applicant, faced with such problems, decided to develop a new bacteria- trapping item which acts not only as a draining and absorbing agent, but above all has a physical-mechanical effect which immobilizes the bacteria in order to keep them away from the fluids so that they reduce their nutrition and consequently the production of secretions, the main cause of bad odors.

The present invention therefore relates, in a first aspect, to a bacteria-trapping item having structural and functional characteristics such as to meet the above requirements and at the same time to overcome the drawbacks mentioned above with reference to the prior art.

This object is achieved by a bacteria-trapping item according to claim 1.

According to a further aspect, the present invention relates to a manufacturing process of a bacteria-trapping item according to claim 8.

According to still further aspects, the present invention relates to possible uses of the bacteria-trapping item according to claims 9 to 12.

Brief Description of the Drawings

Further characteristics and advantages of the bacteria-trapping item and tray, the manufacturing process thereof and the relevant uses thereof according to the present invention will result from the description below of preferred embodiments, given by way of an indicative yet non-limiting example, with reference to the attached illustrations, wherein:

- Figure la shows a cross-sectional view of an axillary pad comprising a bacteria-trapping item having an odor catching function according to the present invention,

- Figure lb shows a cross-sectional view of a tray including a bacteria-trapping item according to the present invention,

- Figure 2 shows a cross-sectional view of a bacteria-trapping item according to a first embodiment,

- Figure 3 shows a cross-sectional view of the item of Figure 2 in which the liquids absorption paths are observed,

- Figure 4 shows a cross-sectional view of a bacteria-trapping item according to a second embodiment,

- Figure 5 shows a cross-sectional view of the item of Figure 4 in which the liquids absorption paths are observed,

- Figures 6a-6d show photographs of some tests performed on the item according to the present invention.

Embodiments of the Invention

With reference to the attached figures, reference numeral 2 globally indicates a bacteria-trapping item 2 according to the present invention.

The bacteria-trapping item 2 (or otherwise known as a “pad”) comprises a filtering layer 2b configured to be crossed by any liquids or fluids along the paths P indicated by the dashed arrows in the illustrations.

The bacteria-trapping item 2 may further comprise a supporting absorbing layer 2a associated with the filtering layer 2b and preferably made from fiber material.

Advantageously, the filtering layer 2b is configured to exert both a partially absorbing effect for the liquids and a blocking effect for bacteria so as to trap them before they reach the absorbing layer 2a, thanks to its cationic properties which will be described in detail later in the present treatise.

In detail, the absorbing layer 2a is a non-woven fabric. It is preferably made from fiber material selected from the group comprising:

- artificial cellulosic fiber (such as, e.g., viscose, tencel, modal, lyocel, cellulose acetate),

- natural cellulosic fiber (such as, e.g., cellulose pulp, cotton, and the like).

Optionally, according to different embodiments, the absorbing layer 2a could also be made from polysaccharide fiber (such as, e.g., alginate fiber).

The absorbing layer 2a may therefore comprise natural cellulose fiber, artificial cellulosic fiber or combinations thereof.

Preferably, the absorbing layer 2a has a weight of between 40 and 200 g/m ² , preferably about 60 g/m ² . Conveniently, the absorbing layer 2a is preferably made from a single natural cellulosic fiber but may also be made by interweaving several fibers together, e.g. by adding polymeric materials such as polyesters, polyolefins, polyamides and/or mixtures thereof.

Similarly, the filtering layer 2b is a non-woven fabric. It too is preferably made from fiber material selected from the group comprising:

- artificial cellulosic fiber (such as, e.g., viscose, tencel, modal, lyocel, cellulose acetate),

- natural cellulosic fiber (such as, e.g., cellulose pulp, cotton, and the like).

Optionally, according to different versions, the filtering layer 2b could also be made from polysaccharide fiber (such as, e.g., alginate fiber).

The filtering layer 2b may therefore comprise natural cellulose fiber, artificial cellulosic fiber or combinations thereof.

Preferably, the filtering layer 2b has a weight of between 40 and 200 g/m ² , preferably about 60 g/m ² .

Conveniently, the filtering layer 2b is preferably made from a single natural cellulosic fiber, but may also be made by weaving several fibers together, for example by adding polymeric materials such as polyesters, polyolefins, polyamides and/or mixtures thereof.

Advantageously, the filtering layer 2b comprises at least one polymeric cationic agent capable of generating an attraction effect on the cell wall of the bacteria. This attraction occurs through differences in potential charges between the aforementioned bacterial cell wall and the surface of the filtering layer 2b, identified in the literature as weak electrostatic interactions (van der Waals forces).

In one version, the polymeric cations of the filtering layer 2b comprise at least one polyamidoamine obtained as an adipic acid/polyethylene polyamine-resin epichlorohydrin copolymer.

The polyethylene polyamine is selected from the list comprising: diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenpentamine (TEPA), pentaethylenesamine (PEHA). In a further version, the polymeric cations of the filtering layer 2b comprise at least one polyisocyanate obtained as a homopolymer or copolymer of at least one of either hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) or isophorone diisocyanate (IPDI).

The polysocyanate comprises a percentage of NCO reactive groups comprised between 5% and 20% by weight of the total weight.

Preferably, the cellulosic fiber of the filtering layer 2b is in a weight amount of between 0 and 90% by weight of the total weight.

Preferably, the cationic agent is present in a weight amount of from 1% up to 20% by weight of the total weight.

The absorbing layer 2a is preferably made from a super absorbing material with an absorption capacity of between 1 kg/m ² and 10 kg/m ² , preferably 2.5 kg/m ² .

According to embodiments not shown, the absorbing layer 2a may also comprise at least one polymeric cationic agent capable of generating an attraction effect on the cell wall of the bacteria.

According to a preferred use, the bacteria-trapping item 2 is usable as a dress shield 10 with an odor trapping function according to the present invention.

As can be seen from the example in Figure la, the dress shield 10 is configured to be applied under the armpit of a user and is made by joining the filtering layer 2b, the latter being intended to be placed in direct contact with the skin of the user, to the absorbing layer 2a.

To the absorbing layer 2a, on the opposite face to that affected by the filtering layer 2b, an impermeable layer 2c may be provided.

According to a further embodiment, the dress shield 10 may comprise one or more adhesive layers 2d applied directly on the absorbing layer 2a (or on the impermeable layer 2c) to secure the dress shield 10 to clothing. Conveniently, the adhesives 2d may be covered by a pair of protective films 3 which are removable at the time of use.

In summary, the dress shield 10 comprises, in use (in sequence from the layer intended to be in contact with the skin towards the outermost layer), a filtering layer 2b, an absorbing layer 2a attached to the filtering layer 2b, an impermeable layer 2c (optional), one or more adhesive layers 2d attached to the impermeable layer 2c (optional), one or more protective films 3 (optional).

According to a further use, the bacteria-trapping item 2 is usable as an insole for shoes with an odor trapping function according to the present invention.

The insole (not shown) is configured to be slipped inside the shoes of a user and is made in a manner entirely similar to the dress shield 10 described above. In particular, the filtering layer is joined to the absorbing layer and the filtering layer is intended to be placed in direct contact with the user’s foot, possibly by means of an interposed sock.

The absorbing layer, on the opposite face to that affected by the filtering layer, may be provided with an impermeable layer and one or more adhesive layers arranged in a manner quite similar to that described with reference to the absorbing layer. The adhesive layers are configured to prevent the insole from slipping inside the shoe during use.

According to a still further use, the bacteria-trapping item 2 is usable inside a food tray 1 as shown in the example of Figure lb.

Preferably, the food tray 1 is a package for containing fresh food, in particular meat, sliced food, fish, vegetables, fruit, etc.

As can be observed, in the tray 1 there is a bottom la from which protrudes upwards a lateral wall lb bordered by an upper edge 1c supporting a possible lid 3.

According to the present invention, the tray 1 may be made from a polymeric material selected from the group comprising: polystyrene, polyethylene terephthalate, polylactic acid, polypropylene, extruded expanded polystyrene, extruded expanded polylactic acid, etc. Other solutions cannot be ruled out wherein the tray is made from different materials depending on the type of food to be packaged or its intended use, such as e.g. cellulose, paper, cardboard and/or biodegradable materials in general.

Advantageously, the tray 2 is configured to accommodate the bacteria-trapping item 2 described above wherein the supporting absorbing layer 2a is intended to be adherent to the bottom la of the tray 1 by means of one or more adhesive layers (not shown) entirely similar to the adhesive layers described above with reference to the dress shield and/or the insole.

With the absorbing layer 2a of the item 2 may be associated the filtering layer 2b, the latter being intended to be placed in direct contact with the food. Preferably, in use, the filtering layer 2b is arranged above the absorbing layer 2a and anchored thereto. When the food is placed in the tray 1, in particular at the bottom la, the filtering layer 2b is configured to be crossed by any food liquids along the paths P and to exert both a partially absorbing effect for the food liquids and a blocking effect for the bacteria so as to trap them before they reach the absorbing layer 2a, thanks to its cationic properties.

According to the second embodiment shown in the examples of Figures 4 and 5, the item 2 may comprise an impermeable layer 2c intended to be placed in direct contact with the food. Preferably, in use, the impermeable layer 2c is arranged above the filtering layer 2b so that the latter is arranged between the absorbing layer 2a and the impermeable layer 2c. According to particular embodiments, the impermeable layer 2b is made from a thermoplastic material, preferably polyethylene, polypropylene or the like. When the food is placed in the tray 1, in particular at the bottom la, the impermeable layer 2c is configured to drain any food liquids along the paths P towards the outside of the item 2 so as to be able to reach the absorbing layer 2a and the filtering layer 2b located below. It should be noted, however, that the absorbing layer 2a is involved in the absorption of liquids only after they have passed through the filtering layer 2b (except for a small part absorbed laterally during percolation). Since the bacteria, due to hydrophilicity, follow the same path as the liquids containing them, the passage through the filtering layer 2b allows carrying out both a filtering effect for the liquids and a blocking effect for the bacteria, so as to trap them before they reach the absorbing layer 2a thanks to its cationic properties, which will be described in detail later on in the present disclosure.

The manufacturing process of the item 2 according to the invention provides first of all for the formation of the supporting absorbing layer 2a starting from cellulosic fiber (artificial or natural) or bulk polysaccharide. The fiber is made to advance in-line by means of typical roller or belt machines and subsequently carded to form a continuous mattress with various surface finishes (e.g., perforated, embossed, smooth). Preferably, the feed speed of the carpet is between 40 and 70 m/min.

Thereafter, an entanglement/needling phase of the carpet is carried out to give compactness to the fiber carpet. The needling phase is carried out with water using high-pressure micro-jets at more than 80 bar (e.g. using the so-called “spunlace” or “hydroentanglement” system).

Finally, the absorbing layer 2a is heated, in order to make the aqueous part evaporate, to a temperature between 80 and 180°C. Preferably, this last heating phase can last a few seconds, e.g. 1 second.

The realization of the filtering layer 2b is carried out similarly to that described for the supporting absorbing layer 2a. Subsequently, the process comprises immersing the filtering layer 2b thus made in an additive mixture containing the polymeric cationic agent described above.

At the end of the process, the absorbing layer 2a and the filtering layer 2b (and possibly the impermeable layer 2c) are joined together to form the pad 2 to which the present invention relates.

By way of an example, by no means limiting, of possible variations within the reach of the technician in the sector, described hereunder in general terms is a composition of a preferred mixture of elements for making the solution containing the cationic agent according to the invention, by suitable mixing, according to known methods, the components in suitable mixing means commonly used in the sector.

Conveniently, the addition of a basic substance (such as, e.g., caustic soda) allows the acidity of the additive mixture to be adjusted so as to maintain a pH value comprised between 7 and 8, as well as to ensure anchorage of the cationic agent on the filtering layer 2b.

Preferably, the above-described process is a continuous process carried out inline. By “continuous process” is meant a process without intermediate stop phases, without in fact rest phases between carding and the exit of the item 2 from the line.

The Applicant has carried out various laboratory tests and analyses which have demonstrated the effectiveness of the bacteria-trapping item 2 in the case of direct contact with food products. In particular, several samples of fresh red raw beef placed inside respective food trays, one containing a standard absorbing pad and one containing the pad 2 to which the present invention relates, were compared. In the tests, the following parameters were measured (the acronyms used in the following tables are shown in brackets):

- Total bacterial count at 30°C (CBT30),

- Enterobacteriaceae (ENT),

- E. coli (ECO),

- Staphylococci coaugulase + (STX),

- Listeria monocytogenes count (CL1),

- Detection of Salmonella spp. (S25).

The meat analyses were carried out immediately after slaughtering at the time tO and at a time tl corresponding to the moment when the food is no longer suitable for consumption and therefore no longer saleable (or so-called “shelf life”).

In a first sampling of red meat placed in a tray with standard absorbing pad and in a tray with pad 2 according to the invention, respectively, the analyses at time tO determined the values shown in Tables 1 and 2.

Table 1

Table 2

In a second sampling of red meat placed in a tray with standard absorbing pad and in a tray with pad 2 according to the invention respectively, the analyses at time tl resulted in the values shown in Tables 3 and 4.

Table 3

Table 4

Furthermore, during the test at time tl exudate was present inside the trays, a measurement was carried out in order to identify whether the pad of the invention could affect absorption at all. It was ascertained that at time tl, the tray with the standard pad had an amount of exudate of 3.6 ml, whereas the tray with the pad of the invention had an amount of exudate of 1.2 ml.

As far as microbiological analysis is concerned, it has been demonstrated that the bacteria-trapping item 2, when inserted inside food trays and in contact with the surface of the food itself, allows for bacterial reduction; in the specific test carried out, a decrease was found in the total bacterial count at 30°C as well as in Enterobacteriaceae with the same storage time compared to the same food inserted in a tray with a standard absorbing pad.

The Applicant carried out further different laboratory tests and analyses to also verify possible migrations of the filtering layer 2b containing the polymeric cationic agent in case of direct contact with food products.

The results of the microbiological analyses are reported according to the provisions of the UNI EN ISO 8199:2008 and UNI EN 150 7218:2013 EC 1- 201 standards. In particular, the following simulants were used:

- Acetic acid 3%,

- Sunflower oil,

- Ethanol 15%, for a contact period of 10 days at 40° C.

In a first sampling, the microbiological analyses resulted in the values indicated in Table 5 for the Acetic acid 3% simulant.

Table 5

In a second sampling, the microbiological analyses resulted in the values indicated in Table 6 for the Sunflower oil simulant.

Table 6 In a third sampling, the microbiological analyses resulted in the values indicated in Table 7 for the Ethanol 15% simulant.

Table 7

From the above conducted tests, it was thus demonstrated that the bacteria- trapping item 2, when placed inside food trays, allows increasing the storage period due to the immobilizing effect on bacteria without, at the same time, contaminating the food by any release of the cationic agents ensuring a safe storage according to food standards.

The Applicant realized that, in addition to its use in food packaging, the bacteria-trapping item 2 is potentially suitable for use in further multiple applications. By way of example and without restriction, the following possible uses have been identified:

- washing,

- filtration,

- clothing, - footwear,

- personal hygiene,

- etc.

For example, other tests and analyses were conducted to validate the effect of bacterial reduction in an aqueous solution under dynamic contact with the bacteria-trapping item 2 of the present invention.

The tests were carried out according to ASTM E2149-2010 (Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents under Dynamic Contact Conditions) using both Grampositive and Gram-negative bacteria at a concentration of 1.5 - 3.0 x 10 ⁵ CFU/ml.

The ASTM E2149-2010 test was chosen as the reference standard because it measures the percentage decrease in bacteria contained in a liquid under conditions of dynamic contact with a sample tissue: it mimics, on a laboratory scale, a domestic washing machine.

During these tests, a domestic detergent was added and the washing temperature was set at 40°C.

The following bacteria were tested:

- Staphylococcus aureus ATCC 6538 (Gram-positive),

- Escherichia coli ATCC 11229 (Gram- negative),

- Klebsiella pneumoniae ATCC 4352 (Gram- negative).

In order to demonstrate that the bacterial reduction is due to the ability to attract and bind bacteria to the filtering layer 2b, it was necessary to assess the vitality of the bacteria themselves before and after contact with the bacteria-trapping item 2.

Various experimental techniques were applied to obtain an effective bacterial detachment for the purposes of analysis, and satisfactory results were obtained with the use of a non-ionic surfactant of type TWEEN 20 (4 g/1) in combination with an ultrasonic bath (260W, 40Khz) for time intervals of half an hour, 1 hour and 2 hours, as shown in Table 8.

Table 8

Furthermore, the assessment of the ability of item 2 to successfully immobilize the bacteria was also carried out by means of other bacterial growth tests according to the ISO 20645/2004 international standard method. In this bacterial reduction test against Staphylococcus Aureus, the bacteria-trapping item 2 was used as well as a normal cotton fabric used as a control sample.

The results show that in the test in which the bacteria-trapping item 2 was used, no bacterial inhibition ring can be seen around the sample (Figure 6a), whereas after removal of the same, a strong bacterial reduction activity can be observed in the portion of agarized medium covered by the bacteria-trapping item 2 (Figure 6b). This phenomenon indicates that the polymeric treatment present on the bacteria-trapping item 2 does not release biocides capable of spreading through the agarized medium.

On the contrary, as shown in Figure 6d taken from the Institute of Biopolymers and Chemical Fibres (IBWCH) bibliography, an inhibition ring can be observed around the samples when the active substances are weakly fixed to the substrate and/or their diffusivity is high.

Finally, the test carried out with a standard control cotton fabric (Figure 6c) did not show any bacterial reduction activity in the material. In addition, Figure 6c shows that colonies other than Staphylococcus Aureus grew around and under the sample.

In view of the results obtained, it was shown that the bacteria-trapping item 2 according to the invention exerts a physical-mechanical action against the bacteria thus classifying itself as a trapping device without a biocidal function.

The Applicant carried out a further series of tests to check the properties of the bacteria-trapping item 2 in order to:

- replicate the wash and trapping test on domestic equipment, and

- replicate the wash and trapping test with different bacterial contaminants. For this purpose, the tests were reproduced according to the UNI EN ISO 14698-1:2004 standard by contaminating the item with four microbial suspensions having different concentrations:

- a concentration of 1.0 x 10 ⁵ CFU/ml to simulate a biocontamination found in a household wash,

- a contamination of 1.0 x 10 ⁹ CFU/ml to simulate a biocontamination found in hospital/industrial washing.

The tested bacteria were Enterococcus Hirae ATCC 10541 and Escherichia Coli ATCC 10536. The fungi tested were Saccharomyces Cerevisiae ATCC 9084 and Aspergillus Niger ATCC 16404.

For each of the suspensions, five bacteria-trapping items were contaminated, namely:

- three items per suspension and per wash cycle,

- two items as positive control.

Two domestic washing machines were used, with a 2-hour wash cycle applied, at a temperature of 40° C and with the addition of 20 ml of classic liquid detergent and a sample of the bacteria-trapping item.

To demonstrate the absorption capacity of the product, the percentage reduction between the average number of bacteria/fungus present on the positive biological indicators (not washed) and the number of bacteria/fungus present on the used biological indicators (washed) was assessed. By definition, washing is deemed effective when this reduction is 99% or more.

Table 9

Table 10

Table 11

Table 12

As can be appreciated from the results obtained and shown in tables 9-12, it was possible to appreciate that the bacteria-trapping item 2 of the present invention was effective in attracting and retaining bacterial and fungal cells.

The Applicant carried out a further series of tests to verify the compatibility of the bacteria-trapping item with contact with human skin. The tests were reproduced according to UNI EN ISO 10993-10 Chapter 6:2009 by performing epicutaneous occlusive tests (so-called patch tests) on twenty volunteers. Skin reactions were assessed 15 minutes and 24 hours after patch removal. The assessment of the skin reactions showed no erythema, edema, dryness, scaling or blistering in any of the volunteers, thus allowing the bacteria-trapping item of the invention to be classified as non-irritant.

Finally, the Applicant carried out a further series of tests to verify the anti-odor properties of the item according to the invention according to the ISO 17299- 3:2014 method by applying isovaleric acid as a standard test substance. These tests showed a percentage odor reduction of between 90% and 96% in all tests carried out compared to the anti-odor power of similar commercial products whose percentage odor reduction was measured in a maximum value of about 60%.

As found from the present description, it has been ascertained that the described invention achieves the intended objects, and in particular the fact is emphasized that by means of the bacteria-trapping item and its manufacturing process described therein it is possible to obtain a product which can be used in a variety of applications.

As is clear from the foregoing, some of the substances which may be used for the purpose of the present invention possess more than one of the aforesaid characteristics at the same time: they may therefore be used for more than one purpose, i.e. to achieve more than one effect at the same time. The combination of the various phases of the process as well as of the elements for making the additive mixture are potentially endless, and obviously a technician in the field, in order to satisfy contingent and specific needs, may make numerous modifications and variations to the method described above, all of which are however contained within the scope of protection of the invention, as defined by the following claims.