3. Ambalarea brânzeturilor

1. 3. Ambalarea brânzeturilor 3.1. Introducere Cheese is the most diverse group of dairy products Manufacture and ripening involvea dynamic and synchronized series of biochemical and microbiological processes, leading to aproduct with typical, refined, and desirable aroma and flavors Product defects, with off-flavorsand odors, textural or surface indices of failure, may result if these events are unbalanced due tointernal or external factors Packaging systems or coating solutions applied either throughout theripening period or during storage may overcome most of the unbalanced reactions and deficienciesof cheeses Cheese is not an inert product:it will continue to ripen after packaging, and the packaging should ideally not interfere withthe natural maturation process, and at the same time it should increase the cheese’s shelf life Thebalance between these two requirements, and the complex and naturally changing nature of theproduct, makes cheese packaging design a challenging task.

2. Each variety of cheese has its own packaging requirements regarding barrier properties to gases, moisture, and light, butthey are divided into two categories: • breathable packaging, which plays a criticalrole in controlling the ripening of the cheese through its moisture and gas permeability characteristics; • this packaging is used for cheese varieties with an active surface microflora (e.g., bacterialsurface-ripened or mold-ripened cheeses) that have a relative short shelf life; • (b) barrier packaging(e.g., vacuum packages) used for hard varieties of cheese, which generally ripen for longtimes in an anaerobic environment and have a long shelf life

3. 3.2. Clasificarea si proprietatile fizico-chimice ale branzeturilor • Criterii de clasificare: • Texture - determined by moisture and fat content • ripening indices • method of coagulation, coupled with other factors • However, from the packaging point of view, it is considered more useful to • divide cheeses into hard, soft, and fresh classes • In addition, processed cheese, which is obtainedfrom a blend of natural cheese heated with water and emulsifying salts and packaged while still hot,represents a distinct class. • Hard cheeses include very hard (e.g., Parmesan from Italy) and hard or semihard cheeses (e.g., SaoJorge from Portugal). • Soft cheeses include semi-soft (e.g., Serra da Estrela from Portugal), soft ripened • cheeses (e.g., Brie or Camembert from France), and blue vein mold ripened (e.g., Roquefortfrom France). • Fresh un-ripened cheese (e.g., Cottage), although soft, is considered separately becauseof its very high moisture content.

4. 3.3. Obtinerea branzeturilor FIGURE 6.1 Schematic representation of fresh and ripened cheese manufacture. T: temperature; t: time,p: pressure, RH: relative humidity.

5. 3.4. Reactii degradative si indici de alterare Claims for low fat and low salt content, lowering cholesteroland risk of osteoporosis, contributing to dental health, and so on are associated with cheese Flavor is developed during aging as a consequence of microbial and enzymic changes to residuallactose and to lactate and citrate. Liberation of fatty acids (lipolysis) andpeptides and amino acids (proteolysis) also occurs. The free fatty acids and amino acids undergosubsequent metabolism to volatile flavor compounds Cheese texture is influenced greatly by themoisture content and its calcium, fat, and fat-in-dry-matter levels However, texturalchanges during ripening are due to solubilization of calcium phosphate, hydrolysis of the caseinmatrix, changes to water binding within the curd, and loss of moisture caused by evaporation fromthe cheese surface

6. Most traditional cheeses are produced with un-pasteurized milk The Canadian Food Premises Regulation allows for thesale of unpasteurized cheese provided that it is stored for 60 days above 2oC This holding periodis intended to encourage competitive organisms that will virtually eliminate the pathogens withinthe cheese However, these cheeses are commonly affected by several defects: undesirable color and pigmentations associated with the uncontrolled growth of microorganisms (molds and yeasts on the surface) Cheeses from pasteurized milk are less prone (predispuse) to loss of quality or safety concerns,because pathogens are destroyed via heat treatment and a specific starter culture is added Some spoilageand pathogenic microorganisms may be present both in unpasteurized milk cheese after a 60-dayripening period and even in pasteurized milk cheese

7. Degradarea indusa de microorganisme • Is related to mold and yeast growth that leads to color spots on the cheese surface or inside • Debaryomyces hansenii, Kluyveromycesmarxianus var. lactis, K. marxianus var. marxianus (the perfect state of Candida kefyr), andSaccharomyces cerevisiae • Typical defects caused by spoilageyeasts are: • gas production • yeasty flavor and other off-flavors • Discolorations • changes of texture • Spoilage mold species for hard, semihard, and semisoftcheeses without preservatives added:Penicillium commune and Pe. Nalgiovense, Pe. brevicompactum, Pe. palitans, Pe. solitum, Pe. roqueforti and Geotrichum candidum • Debaryomyces hansenii and Galactomyces geotrichumprevailed in rennet (cheag) cheeses, and Kluyveromyces marxianus and Pichia membranaefaciens were themain species found in acid-cured cheese • Yarrowia lipolytica is responsible for the browning process related to tyrosine transformationin melanoidins

8. Anaerobic conditions inside packaged cheese must be controlled because Clostridium spp. maygrow and produce gas due to anaerobic fermentation of lactate • Active packagingsystems with antimicrobials and packages with oxygen permeability, maysolve microbial failures • Chemical failures are: • excessive waterloss • rind (crusta) decolorization • due to excessive exudation (transpiratie), off-flavors, and defatted tastes originate fromoxidation (rancidity) or via microbial metabolism (bitterness, rancidity, acidity) • - openings andirregular holes formed by uncontrolled microbial fermentation • These may be prevented via specific andadequate packaging • The water activity, fat and salt contents, and cheese microflora regulate the biochemicalchanges that occur during ripening and determine the flavor, aroma, and texture of the cheese. • The shelf life of the cheese will be mostly affected by temperature, light, O2 and CO2 concentrations,and relative humidity. Temperature is a factor mainly controlled by the distribution chain, butpackaging plays an important role in controlling the effect of light, gases, and humidity. Migrationof packaging components into the cheese must also be considered for food safety reasons.

9. Degradarea indusa de lumina • Light-induced oxidative processes occur when light and from illuminationon retail shelves passes through the packaging material and reaches the cheese surfaceand whensimultaneously there is O2 in the headspace of the package • The sensitivityof dairy products to light depends mainly on the presence of O2 and the photosensitizing agentriboflavin (vitamin B2) • Riboflavin is capable of absorbing energy and initiating an oxidative chainreaction that can leads to the development of off-flavors, the loss of nutrients such as vitamins andamino acids, and the discoloration of pigments • Factors influencing the process: • the amount of light • the amount of O2 present in the package headspace • Light protection offered by packagingmaterials depends on: • Capacitatea de absorbtie • grosime • gradul de cristalizare a materialului de ambalare • Colorarea, pigmentarea, imprimarea si etichetarea ambalajului

10. Degradarea indusa de oxigen Oxygen present in the headspace is available for oxidation reactions, and the amount depends on theinitial atmosphere concentration and on the O2 barrier provided by the packaging material. Vacuum packaging and flushing with a gas or mixture without O2 reduce the O2 content in the headspace. The critical residual levels of O2 depend on the cheese: levels as low as 1% may result in rapidformation of off-flavors for more sensitive cheeses Very low levels of residual O2 can be achievedusing absorbers in addition to modified atmospheres (MAs). The maximum allowable initialamount of O2 also depends on the headspace-volume-to-cheese ratio

11. The longer shelf life of cheeses packaged in MAs is due not only to the exclusion of O2 but alsoto CO2 inhibition of the growth of many spoilage microorganisms Very high concentrations of CO2 can have an adverse effect on cheese taste or aroma, particularlyfor cheeses with higher fat content, therefore, the concentration must be optimized, maximizing the(AM) effect and minimizing any adverse sensory effect. Ineffective packaging processes such as gas flushing and compromised thermoforming or sealingoperations and accidental minor damage during handling or transportation may affect a small fractionof packaged products in MAs, which will undergo spoilage if not repacked Humidityis fundamental for hydrophilic materials, such as polyamide (PA) and ethylene-vinyl alcohol(EVOH) At highertemperatures, more O2 will be available for oxidative processes Suppliers presentpermeability or transmission rate data at standardized conditions (23oC or 38oC) that are not thesame as the storage temperatures used for cheese.

12. Degradarea indusa de umiditate si de pierderea umiditatii At equilibrium, the relative humidity of the surrounding environment inside the package is equal tothe cheese water activity, which influences its microbiological and physico-chemical evolution overtime. Relative humidity has a direct impact on the weight loss and texture of cheese. In unpackagedcheese, water loss depends on the chemical properties of the cheese (particularly salt content)and on the storage conditions, temperature, and relative humidity. In packaged cheese, water loss depends in addition on the permeability to moisture of the packaging material

13. The optimal packaging has a permeability tomoisture that equilibrates the cheese water loss rate with the flux of moisture permeating out of thepackage at a water activity that minimizes the surface-mold growth and simultaneously yields good textural and sensory properties FIGURE 6.3 Water interactions in packaged cheese.

14. Migrarea din ambalaj in branza Migration of monomers (styrene from polystyrene (PS) packages) and additives (plasticizers fromfilms) has been recorded in cheese packaged in plastic polymers. For a given migrant, the rate of migration andthe amount of migrant transferred from the material into the food depend on the contacting material andon the nature of the food Polyolefins, and particularly polyethylene, are amongthe plastics showing highest migration rates for most additives Studies on the migration of diphenylbutadiene,triclosan, and butylated hydroxytoluene (BHT) from low density polyethylene (LDPE) film intocheeses containing different amounts of fat and water showed not only that the fat content influences themigration of lipophilic migrants but also that the ratio of fat to water and the consistency of the cheeseplay an important role

15. 3.5. Ambalarea branzeturilor tari si semitari Hard cheeses such as Parmesan, Mozzarella, Cheddar, Edam, Gouda, and Emmental are ripenedby internal bacteria. These cheeses have a slow rate of ripening because of their low moisture and high salt content. They ripen for very long times in an anaerobic environment, usually in packages with very low permeability, such as coatings, vacuum packaging, or modified atmosphere packaging(MAP) with binary mixtures of CO2 and N2.

16. Filme sintetice depuse pe branzeturi: ceara si dispersii apoase • - Mineral waxes used as coatings - refined hard paraffin, petroleum jelly, and • microcrystalline waxes with various additives • Paraffin wax comprises mostly saturated aliphaticunbranched alkanes with average molecular weights within the range 280–560 Da (carbon chainlength C18–C60), with a branched alkane content of 10–40% (molecular weights 450–800 Da). • Petroleum jelly is a blend of theses waxes and mineral oil • Different colored waxesare used to differentiate cheeses: yellow, orange, black, white, blue, brown, red, purple, and green. • Wax protects the cheese from mold growth and weight loss through moisture evaporation and preventsaerobic ripening because of its barrier to O2. • Mineral waxes present a higher barrier to O2 thanacetoglyceride-based waxes • Water-based dispersions are typically copolymers of ethylene and vinyl acetate. • These coatingsmay be uncolored or pigmented with different colors and are used as carriers for antifungal agentssuch as natamycin (E235), calcium sorbate (E203), and potassium sorbate (E202) • These coatingsare applied in one or several layers and are also applied before the wax layer.

17. Ambalajele vidate si in atmosfera modificata Vacuum packaging and MAP are used particularly for portioned and sliced hard cheese that is more prone to deteriorative changes because of a largersurface area exposed to light and O2, and therefore high-barrier packaging must be used. Multilayerfilms composed of combinations of PA or EVOH as gas barriers and polyolefin-based materialssuch as linear LDPE (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ionomers as moisturebarriers and sealing layers are used. Protection against lipid oxidation is obtained when O2 is excluded byvacuum packaging, even if the cheese is exposed to light Vacuum packaging may have a negative impact on the appearance of some cheeses, particularlythose with typical eyes, such as Emmental (Swiss-type) and Edam or Gouda (Dutch-type), whichmay collapse under reduced pressure. For more resistant cheeses, vacuum skin packaging (VSP) isvery common, with packaging structures with varying O2 barriers.

18. In MAP, the gas mixture should be optimized for each cheese. Some cheeses withstand mixtureswith compositions richer in CO2; others suffer from sensory problems and package collapse MAswhen a higher percentage of CO2 is used. Poly(ethylene terephthalate) (PET) may be used in place of PP for extra mechanical resistance. Gas flushing (inrosirea), among other factors, was found to contribute more than vacuum packaging to the development of calcium lactate crystals (CLCs) in Cheddar cheese after 12 weeks of storage at 7oC. CLCs are a quality and appearance defect detrimental to consumer acceptance.

19. 3.6. Ambalarea branzeturilor moi • Cheeses soft in texture have very variable ripening processes, sensory and physicochemical characteristics,and packaging requirements. • Soft cheeses include: • surface-mold-ripened cheesessuch as Camembert and Brie; • internal-mold-ripened cheeses, also called blue vein type, suchas Roquefort and Gorgonzola; • surface-ripened cheeses such as Havarti and Limburger; • internal-bacteria-ripened cheeses such as Mozzarella • Camembert and Brie are respiring cheeses, and their respiration rate depends strongly on the ageof the cheese and hence the development stage of the surface molds, temperature, and the atmosphereinside the package. • A shelf life can beobtained that ranges from 2 to 3 weeks for cut cheeses to 6 weeks for whole cheeses • These cheeses are packaged in flexible materials, using an outer package of wood • or paperboard. • The permeability of the flexible materials should be tailored to the respiration and • moisture transfer needs of the cheese.

20. Perforated films of oriented polypropylene (OPP) and combinationsof OPP and paper are used with the number, size, and density of perforations varied accordingto the barrier required FIGURE 6.5 OPP/paper packaging material combination for respiring cheeses. Combinations of regenerated cellulose film (RCF) andpaper, wax- or LDPE-coated paper, lacquered aluminum foil, and nonperforated OPP are also usedwhen tighter packs are required.

21. The quality of smear-coated cheeses (branzeturi acoperite cu dtrat de grasime) (Havarti, Limburger, and Munster) is strongly dependenton the vitality of the surface culture (often Brevibacterium linens), which is related to the relative humidity inside the package. A highly controlled humidity inhibits the growth of molds. Packaging barrier to moisture should be well defined in order toallow for equilibrium between the relative humidity surrounding the cheese and the external relativehumidity. Light exposure should also be avoided Packaging in black pigmented laminates [oriented polyamide (OPA)/EVOH/LDPE] provided thebest protection of Havarti cheese MAP has also been used for Mozzarella cheese.

22. 3.7. Ambalarea branzeturilor proaspete Cheeses in the fresh category include Mascarpone, Ricotta, Chevre, Feta, Cream cheese, Quark and cottage cheese, as well as whey cheeses. Due to their high moisture content, low salt concentration,and high pH, fresh cheeses are susceptible to microbial spoilage and consequently have a limited shelf life. They are also very sensitive to dehydration, and, in fact, most fresh cheeses keep drainingslowly. They need to be protected from moisture loss by barrier packages Light(particularly for cheeses with some fat) and O2 can also result in quality deterioration. Someof these cheeses are packed under low O2 conditions in medium-barrier packages with an MA. Typical packages are plastic cups of high density polyethylene (HDPE) or PP, which providea good moisture barrier, and PS.

23. Sealed lids for integrity and snap-on outer lids are common. To provide a higher barrier to O2 and maintain an MA with the correct CO2 level in the headspace tocause its dissolution into the product, the use of high-barrier materials such as PA/LDPE laminatesis essential. The shelf life of Cottage cheese, without chemical preservatives, stored at 3–4oC is 14–21 days. Flushing the headspace (25%) of commercial packages of Cottage cheese with pure CO2 extendedthe shelf life at 8oC by about 150% without altering the sensory properties or causing any othernegative effects.

24. 3.8. Ambalarea branzeturilor procesate Processed cheese is produced by heating a mixture of cheese, water, emulsifying salts (mostlysodium citrates, sodium orthophosphates, or sodium polyphosphates), and further optionalingredients such as butter or spices. Mix constituents and processing conditions are selectedto give the desired structure, appearance, color, flavor, and shelf life at an acceptable cost. Themixture is heated in a batch cooker to 70–120oC under a partial vacuum with constant agitation,until a homogeneous mass is obtained, or in a continuous ultra-high-temperature processat 140oC. Generally the hot processed cheese is filled into the desired packages such as pouchesor polymer-coated aluminum foils. Thereafter, these packages are sealed and the product iscooled. The structure of the processed cheese depends on the type of cheese used, the fat ratio,the dry matter content, and the ability of the emulsifying salt to sequester the calcium The amount of O2 initially dissolved in the product depends on the quantity of O2 introducedinto the product due to the manufacturing process and on the filling methods used.

25. The typical packaging systems used for spreadable processed cheese are: • Squeezable (compresibil) non-barrier tubes made of LDPE, high-barrier tubes made of multilayer materialscontaining EVOH as a barrier layer, or metal tubes. • • Cups made of PP, PET/LDPE, or PS/EVOH/LDPE heat-sealed with alufoil or plasticlaminate. • • Glass cups heat-sealed with an alufoil plastic laminate or with an easy-open tinplate cap. These packaging systems correspond to different amounts of O2 available in the package headspaceand permeating through the package as a consequence of the different barrier properties of theplastic polymers.

26. 3.9. Sisteme noi de ambalare Filme antimicrobiene (AM) • In recent years, AM packaging has attracted much attention because ofthe increase in consumer demand for minimally processed, preservative-free products. • The preservative agents must be applied to packaging in such a way that only low • levels of preservatives come into contact with the food • Probably thefirst application of AM food packaging was in 1954 by Smith and Rollin, who demonstrated thata moisture-proof RCF (regennerated cellulose film) film coated with sorbic acid was effective in prolonging the shelf life ofnatural and processed cheeses by retarding surface-mold growth • AM films can be divided into two types: • those that contain an AM agent that migrates to the surface of the food • those effective against surface growth without the migration of the active agents to the food • Chemical preservatives that can be used in active AM-releasing systems include organic acidsand their salts (primarily sorbates, benzoates, and propionates), parabens, sulfites, nitrites, chlorides,phosphates, epoxides, alcohols, ozone, hydrogen peroxide, diethyl pyrocarbonate, antibiotics,and bacteriocins

27. New AM packaging materials are continually being developed. The enzyme lysozyme is asingle-peptide protein that possesses activity against components of the cell wall of both gram-positiveand gram-negative bacteria. Hydrolysis of the cell wall by lysozyme can damage the structuralintegrity of the cell wall and result in the lysis of bacterial cells Lisozymeand Na2-ethylenediaminetetraacetic acid (EDTA) were effective in prolonging the shelf life of traditionalMozzarella cheese. These AM compounds were incorporated into the typical conditioningbrine of the cheese and significantly inhibited the growth of coliforms and Pseudomonadaceae duringthe first 7 days of storage at 4oC The bacteriocin nisin produced by the lactic acid bacterium Lactococcus lactis is most effectiveagainst lactic acid bacteria and other gram-positive organisms. Nisin is a peptide composed of 34amino acid residues, with a molecular mass of 3.5 kDa and a highly surface-active molecule capableof binding to different compounds, such as fatty acids of phospholipids. This feature makesit suitable for adsorption to solid surfaces and for killing bacterial cells that subsequently adhere

28. For example, inserts of greaseproof, wet-strength paperimpregnated with nisin were placed between portions of sliced Cheddar cheese packaged underMAP Natamycin (or pimaricin) is a polyene antifungal antibiotic produced by Streptomyces natalensis,commonly used to control fungus growth on the surface of many cheeses. Films with a cellulosepolymeric base impregnated with natamycin at concentrations of 2% and 4% inhibited growth ofPenicillium roqueforti in Gorgonzola cheese Antimicrobials based on silver ion zeolites are in use for several applications and have been proposedby AgPolymer as a nonedible cheese coating applied mixed with polyvinyl acetate. Silver hasbeen used throughout history as a means of preventing the transmission of diseases and infections. Silver ions react with negative charges on the bacterial cell wall leading to its destruction and stop the cell enzymic respiratory processes and cause cell metabolism to cease. Silver zeoliteA (silver zinc sodium ammonium aluminosilicate) is approved for food contact use.

29. Many AM systems exploit natural agents. The natural AM compound allyl isothiocyanate (AITC)found in mustard oil is claimed to be effective against cheese-related fungi. It was tested on DanishDanbo cheese, which increases the shelf life from 4 to 13 or 28 weeks, depending on the amount ofAM applied and despite an unacceptable mustard flavor that tends to disappear later in the storageperiod LDPE-based films containing linalool or methyl chavicol (theprincipal components of basil) have been used to retard microbial growth on Cheddar cheese. Bothcompounds retained their AM activity against Escherichia coli after the film was extrusion-blown.

30. Absorbatii de oxigen Active packaging technologies offer the food industry new opportunities for the preservation offoods, and dairy is no exception. For cheese, applications of active packaging currently used are O2 scavengers and moisture absorbers. Oxygen-absorbing systems provide an alternative to vacuum and gas-flushpackaging. Typicalsystems are based on the oxidation of iron powder by chemical means or scavenging of O2 throughthe use of enzymes. Moisture-absorbing substances: silica gel, molecular sieves, natural clays, calcium oxide, calcium chloride, modified starch. The Humidipak system, typically used to control humidity in cigarcases, was adapted and tested to control the relative humidity inside a package of semihard cheese. This technology allows for two-way humidity control by continuously responding to and adjusting the relative humidityby either adding or removing water to maintain a predetermined humidity level. The productconsists of a gelled, saturated solution that is filled into a small sachet made of a material with veryhigh permeability, but that does not allow liquid water to pass through or leak into the package

31. Biomaterialele Biopolymer-based packages contain raw materials originating fromagricultural and marine sources. Polylactate (PLA) is a material made from lactic acid producedby fermentation of starch from corn. It has gained increasing interest as a food packaging materialfor environmental reasons and is particularly studied for use in cheese packaging PLA does not provide a sufficient barrier to O2 and water vapor to prevent lipid oxidationand moisture loss in many cases. If light can be avoided and low storage temperaturesused, this material can be a viable option.