IE912660A1 - New microorganisms and their use for the manufacture of¹delicatessen products - Google Patents

Abstract

New microorganisms such as the strain Debaryomyces hansenii CB5 291.90, which make it possible in particular to form a surface bloom on the skin of charcuterie articles while inhibiting the formation of a contaminating flora, and the use of these microorganisms for the manufacture of charcuterie articles.

Description

NEW MICROORGANISMS AND THEIR USE FOR THE MANUFACTURE OF DELICATESSEN PRODUCTS The present invention relates to new microorganisms which make it possible, in particular, to form a surface bloom on the skin of delicatessen products while inhibiting the formation of a contaminant flora. The invention also relates to the use of these microorganisms for the manufacture of delicatessen products.

It is known that microorganisms such as yeasts or moulds, especially yeasts belonging to the genus Debaryomyces and moulds belonging to the genus Penicillium, may be used for the formation of surface bloom on the skin of delicatessen products, in particular fresh sausages and large, ready-to-eat sausages.

The surface bloom has proteolytic and lipolytic actions, and through these actions enables the taste and aroma of the delicatessen product to be enhanced. In addition, through its appearance, the surface bloom should make the delicatessen product more attractive and more pleasing to the eye. Finally, the surface bloom enables the loss of water by the delicatessen product during its manufacture to be regulated.

However, with the microorganisms used hitherto, the appearance of the surface bloom is imperfect. Thus, the known surface blooms yellow with time. As a result, it is often necessary to remove the surface bloom from the delicatessen product once it has accomplished its proteolytic and lipolytic actions, this being done during an operation referred to as scrubbing. Following scrubbing, it is then common, during an operation referred to as dusting, to add talc or flour to the skin of the delicatessen product in order to impart to it a powdery white surface appearance.

Naturally, these scrubbing and dusting operations represent a loss of time and hence of productivity for the manufacturers of delicatessen products.

Moreover, the surface blooms obtained with the said known microorganisms exhibit poor adhesion to the skin of the delicatessen product.

Finally, the conventional surface blooms, during storage of the delicatessen product, are contaminated by undesirable flora. These contaminants generally take the form of spots of colour on the surface of the delicatessen product. These spots spoil the appearance and even the taste of the delicatessen product. They form after approximately 10 to 15 days after inoculation of the microorganism onto the delicatessen product.

There is hence a great need in the delicatessen industry for microorganisms enabling the drawbacks of the prior art to be overcome and, above all, the formation of contaminant flora to be inhibited.

In the course of these investigations, the Applicant has isolated a microorganism which makes it possible to form a cream-coloured surface bloom which does not yellow with time, the appearance of which is even and powdery, which is not sticky, which avoids scrubbing and possible dusting and, above all, which prevents the formation of contaminant flora.

In addition, the surface bloom thereby formed adheres well to the skin of the delicatessen product. Finally, the said microorganism permits a noteworthy improvement in the taste and aroma of the said delicatessen product.

The invention hence relates to a microorganism, characterised in that it is, in particular, suited to the formation of surface bloom on skins of delicatessen products, and in that it enables the formation of contaminant flora of the said surface bloom to be Inhibited.

The said microorganism can be a yeast, especially a yeast belonging to the genus Debaryomyces, and preferably to the species Debarvomvces hansenii.

In an especially preferred context of the present invention, the said microorganism exhibits the properties of inhibition of contaminant flora of the surface bloom of Debarvomvces hansenii strain CBS..

This strain was deposited with the Centraalbureau Voor Schimmelcultures (CBS) in the context of the Budapest Treaty on 12th July 1990.

Naturally, the said microorganism can take the form of a pure culture. Generally, the contaminant flora whose formation is inhibited by the microorganism which is the subject of the invention contains or generally consists of moulds belonging to the Mucorales group, such as Mucor circinelloides or Mucor plumberus. to the Ascomycetes group, such as Eurotium echlnulatum.

Eurotium herbariorum. Eurotium amstelodami or Eurotium chevalieri. or to the Deuteromycetes group, such as Aspergillus group qlaucus. Aspergillus niger.

Cladosporium herbarum. Fusarium culmorum. Gliocladium roseum. Penicillium brevicompactum, Penicillium corvlophilum, Penicillium cvclopium, Penicillium decumbens. Penicillium digitatum, Penicillium expansum.

Penicillium qlabrum. Penicillium qriseofulvum, Penicillium lanthinellum. Phoma qlomerata, Scopulariopsis brevicaulis, Trichodenma koninqii, Trichotecium roseum or Wallemia sebi.

Moulds belonging to the genus Penicillium are the most common.

According to the nature of these microorganisms, they form spots of different colour and conventionally referred to as blue, green, yellow or grey. In addition, it has been found that, surprisingly, the microorganism according to the invention makes it possible to reduce considerably the number of pathogenic bacteria such as coliforms and, above all, enterococci, Micrococcaceae or psychrotrophic bacteria which can appear on the skin of a delicatessen product. The microorganism according to the invention enables contaminant flora to be inhibited over a period equal to at least one month, and generally greater than 3 months, when the delicatessen product is stored in ambient air. The said delicatessen products are preferably fresh sausages or large, ready10 to-eat sausages based on meat, generally of sheep, cattle, horse and/or pig origin, covered with a skin which can be either a natural casing such as runners, used mainly for dry fresh sausages of the stick type, or fat ends, used for traditional family sausages or rosette salami, or a synthetic casing of a cellulose or collagen nature, used mainly for Arles sausages and for salami and whose diameter can be between 50 and 130 mm.

Runners generally come from the small intestine of sheep, pigs, horses or cattle. Their diameter can be between 15 and 80 mm.

Fat ends usually come from the large intestine of pigs. Their diameter can be between 40 and mm.

The said delicatessen products can also be hams or fresh-sausage type products based on fermented vegetables or fish, mixed or otherwise with meats and covered with a skin.

These meats, fish and/or vegetables may be fermented with ripening ferments conventionally used in delicatessen production.

Another aspect of the invention relates to a yeast whose identification features are essentially those of the said Debaryomyces hansenii strain CBS 291.90, as well as a yeast which is Debaryomyces hansenii CBS 291.90, one of its mutants or one of its recombinants.

Naturally, the said yeast can take the form 10 of a pure culture.

The known taxonomic features of Debaryomyces hansenii strain CBS 291.10 of the Applicant are as follows: 1. Morphological features: a) budding of the cells, b) no formation of arthroconidia, endospores, chlamydospores or ballistoconidia, c) the asci are non-evanescent. 2. Physiological and biochemical features: a) mesophilic strain b) resistant at 0.01 % eyeloheximide c) production of acetic acid negative d) production of ethanol negative e) growth on: D-glucose positive D-galactose positive L-sorbose positive D-glucos amine negative D-ribose negative D-xylose positive L-arabinose positive L-rhamnose positive sucrose positive maltose positive α,α-trehalose positive melezitose positive meliliose negative methyl a-glucoside positive cellobiose positive lactose negative raffinose positive glycerol positive meso-erythritol positive D-glucitol positive D-mannitol positive myo-inositol negative 2-keto-D-gluconate positive D-gluconate positive D-glucuronate negative DL-lactate positive nitrate negative ethylamine positive L-lysine positive •Ε 912660 cadaverine positive fermentation on: glucose negative galactose negative maltose negative sucrose negative lactose negative raffinose negative The manufacture of Debarvomvces hansenii strain CBS 291.90 may be carried out by the preparation in a first stage of an inoculum, and in a second stage by culturing a fermentation medium inoculated with the inoculum. This inoculum may be obtained by inoculation of a medium whose composition can be identical to that of a fermentation medium as described below.

Larger amounts of microorganisms may be obtained by inoculation of a fermentation medium with such an inoculum.

An appropriate fermentation medium can contain at least one carbon source and at least one nitrogen source assimilable by the said strain.

As a carbon source, carbohydrates, among which galactose, sorbose, maltose, dextrose, starch and starch hydrolysates may be mentioned, are preferred.

Dextrose is a preferred carbon source.

As a nitrogen source, an organic nitrogen source, mixed or otherwise with an inorganic nitrogen source, may be used.

As an organic nitrogen source, tryptone, yeast extracts, especially baker's yeasts, brewer's yeast, lactic yeasts, corn steep liquor, fish meals, caseins and caseinates may be mentioned.

A mixture of tryptone and yeast extracts is preferred. If such a mixture is used, the ratio of typtone to yeast extracts is generally between 10:90 and 90:10.

Generally, the concentration of the carbon 10 source in the fermentation medium is between 5 and g/1, and preferably between 15 and 40 g/1.

In addition, the fermentation medium can contain inorganic salts, preferably magnesium and manganese phosphate salts and especially alkali metal, alkaline earth metal or ammonium phosphate salts such as diammonium dihydrogen phosphate as well as manganese and magnesium sulphates.

The concentration of the said inorganic salts in the fermentation medium is generally between 0.1 and 4 g/1, and preferably between 1 and 3 g/1.

Finally, the fermentation medium can comprise adjuvants conventionally used in such a medium, such as, for example, antifoams and antioxidants.

During the manufacture of Debaryomyces hansenii strain CBS 291.90 by fermentation of a medium such as that described above, the temperature is generally adjusted between 20 and 30*C.

The pH may be adjusted at the start to between 5 and 7 and be maintained between such values during the fermentation.

At the end of an operation of manufacture of the microorganism, that is to say generally after more than 30 hours and preferably between 30 and 40 hours, after inoculation of the fermentation medium, the fermentation medium is cooled, where appropriate, to a temperature of the order of 20 C and the microorganisms manufactured are then recovered.

Recovery of the microorganism may be carried out by any conventional physical means of separation which enables the fermentation medium to be substantially separated from the microorganisms. Preferred separation means are filtration and, more preferably, centrifugation.

Following recovery of the microorganisms, the latter may be packaged in a conventional manner so that they can be stored over a long period of time. Thus, the said microorganisms may be frozen or lyophilised.

Lyophilisation is carried out in the presence of conventional lyophilisation vehicles such as milk, sucrose, lactose or glutaminic acid.

Once lyophilised, a Debarvomvces hansenii strain CBS 291.90 may be kept without loss of viability for more than 6 months at 4*C or for more than one year at -25’C.

Another subject of the present invention consists of a combination between the microorganisms described above and at least one other microorganism, one of whose features is to be able to form a surface bloom on the skin of a delicatessen product. The said other microorganism can be a mould, preferably a mould belonging to the genus Penicillium. The species Penicillium nalqiovensis. Penicillium chrysoqenum and Penicillium candidum are more especially preferred.

Such a combination can consist of 5 to 95 % of microorganisms forming the subject of the present invention, such as Debarvomvces hansenii CBS.., and 95 to 5 % of at least one other microorganism.

The present invention also relates to the use of the said microorganisms or combinations described above for the manufacture of delicatessen products, and preferably delicatessen products covered with a skin.

Delicatessen products possessing a skin coated with a surface bloom consisting of a microorganism or a combination as described above also form part of the present invention. These delicatessen products are preferably fresh sausages and large, ready-to-eat sausages, generally based on meat, but can also consist of delicatessen products such as those described above and which can, in particular, contain or be based on fermented vegetables or fish.

These delicatessen products may be prepared, in particular, according to a process which consists in inoculating a primary delicatessen product, that is to say one not covered with a surface bloom, in particular by dipping, showering or spraying in or by means of an aqueous suspension of the said microorganisms, yeast or combination, and then, where appropriate, in treating the said delicatessen product in an incubator and/or drying it.

The said aqueous suspension can, in addition, contain at least one edible salt such as sodium chloride and/or at least one edible organic acid such as lactic acid.

Dipping is a conventional operation in delicatessen production, consisting simply in dipping the delicatessen product in the said aqueous suspension. Showering, known per se, consists in sprinkling the delicatessen product with the said aqueous suspension and in recycling the latter.

For dipping and showering, suspensions containing from 1 x 1010 to 5 χ 1012 microorganisms per 50 litres of water, and optionally from 10 to 150 g/1 of an edible salt and up to 1 g/1 of the said edible organic acid, are generally used.

For spraying, suspensions containing from χ 1010 to 5 χ 1012 microorganisms per 10 litres of water, and optionally from 10 to 20 g/1 of an edible salt and up to 1 g/1 of an edible organic acid, are generally used.

Following inoculation, the delicatessen product may be treated in an incubator in a conventional manner, for example at temperatures of between 15°C and 35°C for 1 to 8 days and at a relative humidity of between 60 and 100 %. Treatment in an incubator permits acidification and coloration of the delicatessen product and an initial removal of water.

Finally, the delicatessen product may be dried, also in a conventional manner, for example at temperatures of between 10 and 15eC for one week to three months and at a relative humidity of between 70 and 80 %. Drying enables the removal of water to be completed. Drying is the stage during which the surface bloom mainly develops. Apart from the advantages mentioned above, the microorganisms according to the invention enable the drying time to be decreased significantly.

In the case where the said delicatessen product is a fresh sausage or a large, ready-to-eat sausage, if the skin is made of runners, it is preferable to incubate with a dispersion chiefly containing a microorganism according to the invention, such as Debarvomvces hansenii CBS 291.90. If the skin consists of fat ends or an artificial casing, it is then preferable to use a combination according to the invention.

The examples which follow are intended as illustrations of the present invention.

EXAMPLE 1: Preparation of a dry fresh sausage by showering a) To prepare the mixture, the following are minced g/kg 0.05 g/kg g/kg g/kg g/kg in a meat grinder: - fat (back bacon) 30 % by weight lean meat (shoulder of pork) 70 % by weight to which there are added: NaCl potassium nitrate - dextrose - sucrose garlic ripening ferments (Lactobacillus and Staphylococcus) b) The mixture is encased in runnings; the mixture is at a temperature of 0*C. c) Inoculation of the surface bloom: An inoculation of the encased mixture is performed by showering by means of a dispersion containing: 1 of potable water x 1010 Debarvomvces hansenii CBS 291.90 cells per litre of potable water g/1 of NaCl d) Incubator treatment and drying: The inoculated delicatessen product is placed in an incubator: at 24*C for 8 hours 25 (relative humidity 95 %) the temperature is then decreased steadily to 15*C in the course of 40 hours - finally, the delicatessen product is dried in an drier for 10 days at 12 °C (relative humidity 76 %) The fresh sausage thereby produced is dry to the touch and does not have spots of colour, thereby demonstrating the absence of contaminants, even three months after its preparation.

The bacterial population present on the skin of the sausage was counted. The results obtained appear in Table I below. These results are expressed as the number of cells per cm2 of skin surface of the delicatessen product.

EXAMPLE 2 (comparative) The procedure is as in Example 1, but the encased mixture is showered by means of a dispersion containing Penicillium nalqiovensis PNT 1, marketed by the company Lacto Labo, in place of Debarvomvces hansenii CBS 291.90.

The fresh sausages thereby prepared have to be dried for 17 days. They are sticky and have blue spots. The count of the bacterial population appears in Table I below.

EXAMPLE 3: Preparation of a dry fresh sausage by dipping The procedure is as in Example 1, but the encased mixture is dipped instead of being showered.

The dipping is carried out in the same dispersion as that used for showering.

The dry fresh sausages obtained exhibit the same features as those of Example 1.

EXAMPLE 4 (comparative) Dry fresh sausages are prepared as in Example 3, but the dispersion contains Penicillium naloiovensis in place of Debaryomyces hansenii CBS 291.90. These sausages are sticky and possess green spots on their surface.

EXAMPLE 5: Preparation of a dry, large, ready-toeat sausage a) To prepare the mixture, the following are minced in a meat mincer: fat (back bacon) pork 40 % by weight 60 % by weight lean meat (shoulder of or horse) 15 to which there are added: - NaCl 28 g/kg - potassium nitrate 0.055 g/kg dextrose 5 g/kg lactose 2.4 g/kg 20 garlic 3 g/kg ripening ferments (Pediococcus and Staphylococcus) b) The mixture is encased in a cellulose casing. c) Inoculation of the surface bloom An inoculation of the encased mixture is performed by showering by means of a dispersion containing: 1 of potable water lx IO10 Debarvomvces hansenii CBS 291.90 cells per litre of potable water - 10 g/1 of NaCl - 0.1 g/1 of lactic acid d) Incubator treatment and drying The inoculated delicatessen product is placed in an incubator for 40 hours at 24°C and then in a dryer for 4 weeks at 12*C at a relative humidity of 78 %.

The dry, large, ready-to-eat sausage thereby obtained has a cream-colored, adherent, even, powdery surface bloom. It does not have spots of colour, even after three months of storage in ambient air.

EXAMPLE 6: (comparative) The procedure is as in Example 5, but the showering is carried out by means of a dispersion containing 10 1 of water in which a mixture containing 1 χ 1010 Penicillium nalqovensis spores and 5 χ 1010 cells of a conventional strain (not falling within the scope of the present invention) of Debarvomvces hansenii is suspended. Such a mixture is marketed by the company Lacto Labo under the brand name LEM. The said dispersion also contains 10 g/1 of NaCl.

The large, ready-to-eat sausage obtained has an uneven, thick surface bloom whose appearance Is sticky.

The sausage has blue spots.

Table I Population/cm2 Surface bloom Consisting of of surface Debarvomvces hansenii Penicillium naleiovensis CBS 291.90 PNT 1 Coliforms less than 10 less than 10 Enterococci 70 750 Psychro trophic less than 10 600 bacteria Kicrococcaceae 24 x 103 18 X 106

Claims (20)

1. Yeast whose identification features are essentially those of Debarvomvces hansenii strain CBS 291.90. 5

2. Yeast according to claim 1, characterised in that it is a yeast of the species Debarvomvces hansenii deposited with the CBS under number 291.90, one of its mutants or one of its recombinants.

3. Yeast according to one of claims 1 and 2, 10 characterised in that it is in the form of a pure culture.

4. Process for manufacturing a yeast according to one of claims 1 to 3, characterised in that a fermentation medium containing at least one assimilable 15 carbon source and one assimilable nitrogen source is inoculated by means of an inoculum, in that the fermentation medium is fermented and in that the said yeast is recovered.

5. Application of a yeast according to one of 20 claims 1 to 3 to the formation of surface bloom on skins of delicatessen products and for inhibiting the formation of flora contaminating the said surface bloom.

6. Application according to claim 5, 25 characterised in that the said contaminant flora contains or essentially consists of moulds.

7. Application according to one of Claism 5 and 6, characterised in that the inhibition of the formation of contaminant flora is observed for at least one month, and generally more than three months, after an inoculation of the said yeast onto the skin of a delicatessen product. 5

8. Combination of a yeast according to one of claims 1 to 3 with at least one other microorganism suited to the formation of a surface bloom of the skin of a delicatessen product.

9. Combination according to claim 8,

10. Characterised in that the said other microorganism is a mould, preferably a mould belonging to the genus Penicillium and more preferably to the species Penicillium nalqiovensis. Penicillium chrvsoqenum and Penicillium candidum. 15 10. Use of yeast according to one of claims 1 to 3 or of a combination according to one of claims 8 and 9 for the manufacture of delicatessen products, and preferably delicatessen products covered with skin.

11. Process for manufacturing delicatessen 20 products, characterised in that a primary delicatessen product is inoculated, in particular by dipping, showering or spraying in or by means of an agueous suspension of a yeast according to one of claims 1 to 3 or of a combination according to one of claims 8 and 9, 25 and the said delicatessen product is then, where appropriate, treated in an incubator and dried.

12. Process according to claim 11, characterised in that the said aqueous suspension contains, in addition, an edible salt such as sodium chloride and/or an edible organic acid such as lactic acid.

13. A yeast according to claim 1, substantially as hereinbefore described.

14. A process for manufacturing a yeast according to claim 1, substantially as hereinbefore described and exemplified.

15. A yeast according to claim 1, whenever manufactured by a process claimed in claim 4 or 14.

16. An application according to claim 5, substantially as hereinbefore described.

17. A combination according to claim 8, substantially as hereinbefore described.

18. Use according to claim 10, substantially as hereinbefore described.

19. A process according to claim 11 for manufacturing delicatessen products, substantially as hereinbefore described and exemplified.

20. A delicatessen product whenever manufactured by a process claimed in any one of claims 11, 12 or 19.