Description

The subject of the present invention with the introduction of high pressure technology referred to as HPP, used in the production of buffalo milk mozzarella, for the main purpose to extend the shelf life, that is, to delay the structural degradation and the reduction of the microbial load present in the finished product, and at the same time reduce chemical and physical treatments whilst maintaining the integrity of the traditional product.

The market for products that are consumer ready has to deal with a buyer that is increasingly aware in regards to issues such as health, nutrition, diet, obesity and food safety. The demand for less processed products that are not subjected to manipulation, without compromising the nutritional values (vitamins, minerals, antioxidants) by industrial processes without the use of additives or preservatives, and at the same time maximise hygiene and safety.

To meet the demand for food freshness and safety, there is a need for new technology introduced into traditional food processing, in this case the production of mozzarella made entirely from buffalo milk. HPP (High pressure processing) which has been known for some time, allows to _. store food in a state that is very close to their natural state, quality, colour, texture, taste, and nutritional content that extends the shelf-life and renders the food entirely safe and hygienic.

HPP essentially consists of a hydrostatic chamber where pre-packaged products are loaded. The chamber is then pressurised by pumping internal fluid (water), which transmits the pressure to the product according to the principle of Pascal on all points of the product that are stressed by the same pressure, so that the product remains intact. The process is a substantially cold treatment, with the benefit of the sensory characteristics and nutritional food. The inactivation of microorganisms is linked to the action of the high pressure reached, which causes inactivation of the bacterial cells. Because of the considerable high pressures needed, the chamber has a unique design and characteristics that determine the high costs to manufacture the equipment.

There are several known patents that describe the application of this technology of high pressure on food. For example, US Pat. No. 5,213,029 describes a method for subjecting foods to high pressure, but it is a very complicated technique, and temperatures or pressures in use are not specified.

It is not known, however, no application of the use of high pressure, in the production of buffalo milk mozzarella, in particular Mozzarella di bufala campana. How ever there is an example of patent EP 1565059 Al (WO2004045295A1) which describes methods to delay or inhibit the breakdown of casein in cheese with treatments at high pressure, greater than 400MPa. The said patent also speaks of mozzarella, but it is reported in the use for the production of pizza cheese, which has nothing to do with the product fresh mozzarella for consumption, and in particular that of buffalo milk, nor with the buffalo mozzarella niche, where the technological requirements for the application of high pressures are much more stringent.

The same applies to the work of J. J. Sheehan et al. "High pressure treatment of reduced-fat mozzarella cheese: effects on functional and rheological properties" in Innovative Food Science & Emerging Technologies. Vol.3, No.l That use of HPP treatment on a mozzarella with a low fat content, the results of that treatment with HPP had no advantage in terms of improving the consistency and the rheological behavior of mozzarella.

Other work performed by Ciara And, O'Reilly et al., "The effects of high pressure treatment on the rheological and functional properties of Mozzarella cheese" in Innovative Food Science & Emerging Technologies. Vol.6, n ° 1. This uses a mozzarella with a low humidity "Dry" and treated with HPP in the phases of storage at 4 ° C. - As a result, there was an increase in the water retention capacity of the matrix paracasein and an increase in the fluidity of the cheese when heated. At maturation, this type of mozzarella could be used in an industrial application. Which, as mentioned earlier, should be excluded in the present invention.

Taking into account that these works served different purposes from those of the present invention, it is also to be considered that the preparation in production for "mozzarella" used are different; in fact in the first case (Sheehan JJ et al.) used a low- fat mozzarella, in the second case (Ciara And, O'Reilly et Al.) mozzarella with low humidity. Two essential parameters of manufacturing that do not correspond with those used in the buffalo mozzarella. Mozzarella production methods used in the above are notably different to the production methods used for the buffalo mozzarella. Without wishing to make any denigration, the only counterpart is the shape, the color, the presence of milk, and the term "mozzarella". The immense difficulty to adapt industrial technology HPP to increase the shelf-life of a product like buffalo mozzarella, known throughout the world, without depriving it of its organoleptic characteristics is the primary purpose of this patent application.

As we know the technology of production of the Mozzarella di Bufala Campana is defined by a product specification that can be read in

www.agraria.org/prodottitipici/mozzarella. htm ?q=001 ".

According to this Consortium the "Mozzarella di Bufala Campana" is produced exclusively with whole buffalo milk fresh. The milk must:

i. Must possess total minimal fat by 7.2%;

ii. Must have a minimum protein content of 4.2%;

iii. Milk is delivered to the factory, appropriately filtered by conventional means and converted into Mozzarella di Bufala Campana before the 60th hour after the first milking; acidification of the milk and the curd is obtained by adding of natural whey, resulting from previous processing of buffalo milk; coagulation, after heating the milk to a temperature of 65 ° to 90 ° c. By adding natural calf rennet; the maturation of the curd takes place under whey for a variable time in relation to the position of lactic acid present in the natural whey added, but oscillating around five hours from the adding of the rennet (until reaching the pH of level, normally between 4.8 and 4.9). At the end of ripening, after stopping on the drain table, the curd is reduced to strips, chopped and placed in appropriate tubs, also made of steel or spinners. The curd, after mixing not with boiling water, (between 90 and 99 degrees C.) is stretched, and then severed and / or formed (hot) into individual pieces in the forms and dimensions provided. These latter, are placed in clean water for a various times according to the size, up to firming. Salting is done in brine for a various time, depending on the size and concentration of salt brine, which follows immediate packaging, bearing the mark of DOP to be made at place or production. The product must stay in its own salted brine until final consumption.

The adoption of this specification is fine for a product essentially artisanal, with a limited production and consumption in practice and in a limited geographic region, having a limited product freshness with a few days, so little incentive for the products to be sent to places abroad if so at a very high cost.

The problem is aggravated precisely during the period of greatest market demand, which is in the summer months, but also the production of milk is less and therefor the market needs do not correspond with availability of fresh milk. A further limitation arises as part of the DOP or PDO system the ban any use or procurement of buffalo milk from outside the DOP area, while stressing the absolute prohibition of using frozen milk or semi-finished products. Therefore it is necessary for the milk products to come from buffalo reared in the geographical area specified in the permissible areas.

The regulations are designed for production facilities to create a kind of lung at times of surplus raw materials to meet market needs like the production of curd. In practice, the curd needs to be kept at a temperature that will stop the lactic fermentation, thus opening the opportunity to use "frozen curd" which is prohibited by the consortium and contradicts the law that mozzarella must be produced within 60 hours of milking, while the proposal of the frozen curd seems attractive to producers as it no longer needs to be within this limit and can be processed further without any time limit, however would no longer carry the DOP status.

The optimal solution would be to increase the shelf life of the mozzarella over the current 20 days. Except that the extension of shelf life cannot be separated from the reduction of demineralization of the curd and the finished product. It is well known that the conventional technology described in the specification, gives a result of a demineralized product with a tendency to become liquid or creamy as a result of the degradation of proteins that constitute the cheese. These proteins, caseins, are actually protein aggregates stabilized by Calcium Phosphate. A strong acidification of the milk and the curd involves the solubilisatton of phosphates and the

disintegration of the structure typical of Micellar Casein proteins. The kinetics and intensity of this process may affect the structure of the finished product.

Less unstructured proteins are essential for the maintenance of the fibrous structure that is typical of fresh mozzarella.

Moreover, the method of salting and the traditional preservation give a product with a high content of sodium chloride (> 1%) and with the formation of a "crust" on the surface. The two things are opposed to the extension of shelf life since high amounts of sodium in the finished product will replace the native protein to calcium accentuating and accelerating the processes of destabilization of the protein, which has been previously stated.

Regarding the microbiology Mozzarella di Bufala Campana is normally characterized by: heat treated milk at a low temperature, acidification with a culture of thermophilic microorganisms highly acidifying, spinning of the curd with water at high temperature, cooling and salting in brine acid preservation in a liquid brine acid (pH below 4).

In these conditions, the microorganisms represent a constant problem during storage of the mozzarella and are represented by yeasts. The substrate would be also ideal for the growth of mold, but the immersion of the product in a liquid prevents development. Some known protein structures are modified by treatment at high pressures. With regard to milk proteins, the changes undergone by the proteins in cheese are very dependent on the characteristics of the same cheese: cheese made from curds "lactic" undergo very important changes to the structure as opposed to cheeses obtained from curd rennet.

It is also known that the treatment of high pressure favors the liquidification

"Mushy" or "spreadable" and accelerates the ripening of the cheese.

And 'necessary, therefore, to introduce changes in technology to make sure that the structure of the mozzarella cheese is not destroyed by the treatment to high pressure. With the proposed technology, object of the present invention, the casein of the milk, richer in calcium phosphate and with a tertiary structure similar to that naturally present in milk, has characteristics close to that present in rennet-curd cheeses (for example the Burgos) for which the technology of high pressures has given the best results.

So in the proposed technology, object of the present invention, the acidification of the curd will be decreased, bringing it close to zero, and the pH of spinning increased with the aim to obtain a mozzarella with a ratio Ca / casein higher. Furthermore, the salt content is reduced to a maximum of 0.7%. The steering fluid will contain only water and salt from 1.2% to 2%.

However, not using brines and conservation liquid acids, also other bacteria find ideal growth conditions, in particular Enterobacteriacae, Psuedomonaceae and other microaerophilic microorganisms.

The treatment at high pressures must guarantee sterility "technical" essential for prolonging the shelf life is the desired main purpose of the present invention.

In particular, in a first embodiment of the present invention, the process of production of mozzarella will be amended as follows: the whole buffalo milk is heated at a temperature of 65 ° C, cooled to 35 ° C, and inoculated with natural is

with continuous molding at a temperature of 65 " C.

The cooling is extended until reaching a temperature of 10 ° C in the center of mozzarella.

The packaging in flexible casings of PET or flexible Poly Propylene, welded thermally, without kinks and airtight, it is carried out with minimum air possible and with the addition of fresh water with salt percentage of 1.2%.

The product thus packaged is placed in a chamber for high pressures.

The treatment at high pressures is carried out at "24 hours" from the production, at a pressure of 5000 bars for a time of three minutes. In other preferred forms of this process also the treatment to high pressure is carried out with a mozzarella vacuum packed and always to 24 hours after production. It can also use a pressure of 4000 bars for a time of 5 minutes, or at a pressure of 6000 bar for a time of two minutes. After the packaged mozzarella is kept between + 4 ⁰ C and + 6 ° C constant, whilst keeping consistent temperature and normal conditions of transport and storage. The mozzarella cheese, packaged and treated with the above process, have been subjected the next day and after 10, 20, 30, 40, 50, 60 days to the following evaluations and analyses: Sensory evaluation: a panel of three experts and trained tasters to judge buffalo mozzarella produced with traditional technology, have evaluated surface appearance, shape, color, taste, texture, flavor, which confirmed the full compliance

( ^■

of the mozzarella for all parameters. In particular the excellent results regarding the flavor and texture, taste the last 60 days from the date of manufacture, confirm the validity of the technology used and the treatment at high pressure to extend the preservation of buffalo mozzarella. The possible improvement is relative to the flavor linked to a low salt content, of 0.65% - 0.70%. The salt content can be increased up to 1% so that the flavor can be increased, but does not affect the overall product.

The table 1 shows, according to a score ranging from 5 to 7, the result obtained. Table 1. Organoleptic Valuations

Microbiological analysis has carried out the search of Enterobacteriaceae,

Psudomonaceae, Charging total (including the charge lactic), yeasts and molds. At the time of 0, 30 and 60 days and was carried Salmonella, Listeria, coagulase positive.

The methods used were the following:

Coliforms ISO 4832 2006

Escherichia coli NF ISO 16649-2.2001

Molds NF V 08-059 2002

Yeast NF V 08-059 2002

Pseudomonas ISO 11059 2009 / IDF 225

Salmonella AFNOR BIO 12 / 10-09 / 02

Listeria AFNOR BIO 12 / 2-06 / 94

Staphil NF EN ISO 6888-2-1999

The results are expressed in cfu / g.

The results for Salmonella and Listeria are expressed on 25 g.

The results are consistent with the taste test feedback made by the microbiologists. The absence of coliforms and pseudomonads and a count lower than or close to 1000 cfu / g for all other microorganisms confirm that the binomial time / pressure adopted is sufficient to obtain a reduction of the microbial load functional for the extension to shelf life.

Tables 2 and 3 show in summary these encouraging results.

Table 2. Microbiological Results ^' |0 days lOdays 20days 30days 40days 50days 60days

Coliform <10 <10 <10 <10 <10 <10 <10

Escherichia ;<io <10 <10 <10 <10 <10 <10

CBT 800 1000 1200 1200 1000 1100 1000

Mold ^■ J<10 <10 <10 <10 20 10 <10

Yeast <10 <10 20 10 10 <10 100

Table 3. Results microbiological. Pathogens

Chemical analysis: we analysed the following parameters: Fat Matter, Humidity and Salt.

The chemical and physical parameters (humidity is approx 60% and 55% fat in dry matter) both typical in the production of Mozzarella di Bufala Campana and also in accordance with the specification of the OOP consortium.

Table 4. Results of the chemical / physical

Humidity% 60,1 60,5 61,0 59,8 59,6 59,8 59,5

Salt % 0,65 0,70 0,68 0,70 0,65 0,65 0,65

Final evaluations

The taste test was performed at 60 days after production with the conclusion that the proposed technology, combined with the treatment at high pressure under the above conditions, object of the present invention, is suitable for the production of Mozzarella fresh food ready for consumption for milk mozzarella or even buffalo mozzarella di Bufala Campana, with extended shelf life to 60 days. None of the phenomena of microbiological spoilage has occurred, and the changes to the traditional technology have made it possible to avoid the loss of the structural properties that is normally caused by treatment with high pressure treatment of mozzarella.

The increase from 20 to 60 days of shelf life of Mozzarella di Bufala Campana is a technological innovation and is essential for the expansion of the geographical product sales and logistics costs. The economic impact throughout the supply chain is considerable.

Changes to traditional technology proposed and implemented do not violate the rules contained in the specification and the product obtained is in effect defined as Mozzarella di Bufala Campana.

The same process, with the goal of achieving the increased shelf life to 60 days (or even 90 days) and the absence of treatments that decrease the nutritive value and without the stringent limitations due to the specification of the buffalo mozzarella is applicable the mozzarella made from buffalo milk and cow's milk mozzarella, and also apply the same considerations, but on much larger scale economically.