Influence of presalting and brine concentration on salt uptake by Ragusano cheese

The impact of presalting and nonsaturated brine on salt uptake by Ragusano cheese was determined. The study included four treatments: 1) the traditional method using no presalting and saturated brine, 2) presalting and saturated brine, 3) no presalting and 18% brine for 8 d followed by 16 d in saturated brine, and 4) presalting and 18% brine for 8 d followed by 16 d in saturated brine. Cheese blocks were weighed and sampled before brine salting (time 0) and after 1, 4, 8, 16, and 24 d of brining for each treatment. Presalting delivered 60% of the normal level of salt in the center of the block prior to brine salting without decreasing the rate of uptake of salt from either saturated or 18% brine. Use of 18% salt brine for the first 8 d of 24 d of brine salting increased the rate of salt uptake, compared with 24 d in saturated brine. The increased rate of salt uptake with 18% brine compared with saturated brine was related to the impact of salt brine on the moisture content and porosity of the cheese near the surface of the block. Brine with higher salt content causes a rapid loss of moisture from cheese near the surface of the block. Moisture loss causes shrinkage of the cheese structure and decreases porosity, which impedes moisture movement out and salt movement into the block. The use of 18% salt brine for the first 8 d delayed the moisture loss and cheese shrinkage at the exterior of the block and allowed more salt penetration.     

Influence of the temperature of salt brine on salt uptake by Ragusano cheese

The influence of temperature (12, 15, 18, 21, and 24 degrees C) of saturated brine on salt uptake by 3.8-kg experimental blocks of Ragusano cheese during 24 d of brining was determined. Twenty-six 3.8-kg blocks were made on each of three different days. All blocks were labeled and weighed prior to brining. One block was sampled and analyzed prior to brine salting. Five blocks were placed into each of five different brine tanks at different temperatures. One block was removed from each brine tank after 1, 4, 8, 16, and 24 d of brining, weighed, sampled, and analyzed for salt and moisture content. The weight loss by blocks of cheese after 24 d of brining was higher, with increasing brine temperature, and represented the net effect of moisture loss and salt uptake. The total salt uptake and moisture loss increased with increasing brine temperature. Salt penetrates into cheese through the moisture phase within the pore structure of the cheese. Porosity of the cheese structure and viscosity of the water phase within the pores influenced the rate and extent of salt penetration during 24 d of brining. In a previous study, it was determined that salt uptake at 18 degrees C was faster in 18% brine than in saturated brine due to higher moisture and porosity of the exterior portion of the cheese. In the present study, moisture loss occurred from all cheeses at all temperatures and most of the loss was from the exterior portion of the block during the first 4 d of brining. This loss in moisture would be expected to decrease porosity of the exterior portion and act as a barrier to salt penetration. The moisture loss increased with increasing brine temperature. If this decrease in porosity was the only factor influencing salt uptake, then it would be expected that the cheeses at higher brine temperature would have had lower salt content. However, the opposite was true. Brine temperature must have also impacted the viscosity of the aqueous phase of the cheese. Cheese in lower temperature brine would be expected to have higher viscosity of the aqueous phase and slower salt uptake, even though the cheese at lower brine temperature should have had a more porous structure (favoring faster uptake) than cheese at higher brine temperature. Therefore, changing brine concentration has a greater impact on cheese porosity, while changing brine temperature has a larger impact on viscosity of the aqueous phase of the cheese within the pores in the cheese.     

Lipolysis and proteolysis in Ragusano cheese during brine salting at different temperatures

The influence of temperature (12, 15, 18, 21, and 24 degrees C) of saturated brine on lipolysis and proteolysis in 3.8-kg blocks of Ragusano cheese during 24 d of brining was determined. Twenty-six 3.8-kg blocks were made on each day. The cheese making was replicated on 3 different days. All blocks were labeled and weighed prior to brining. One block was sampled and analyzed prior to brine salting. Five blocks were placed into each of 5 different brine tanks at different temperatures. One block was removed from each brine tank after 1, 4, 8, 16, and 24 d of brining, weighed, sampled, and analyzed. Both proteolysis and lipolysis in Ragusano cheese increased with increasing brine temperature (from 12 to 24 degrees C), with the impact of brine temperature on proteolysis and lipolysis becoming progressively larger. Proteolysis was highest in the interior of the blocks where salt in moisture content was lowest and temperature had more impact on proteolysis in the interior position of the block than the exterior position. However, the opposite was true for lipolysis. The total free fatty acid content was higher and temperature had more impact on lipolysis at the exterior position of the block where salt in moisture was the highest. This effect of increased salt concentration on lipolysis was confirmed with direct salted cheeses in a small follow-up experiment. Lipolysis increased with increasing salt in the moisture content of the direct salted cheeses. It is likely that migration of water-soluble FFA from the brine into the cheese and from the interior portion of the cheese to the exterior portion of the cheese also contributed to a higher level of FFA at the exterior portion of the blocks. As brine temperature increased the profile of individual free fatty acids released from triglycerides changed, with the proportion of short-chain free fatty acids increasing with increasing brine temperature. This effect was largest at high salt in moisture content.     

Composition of Ragusano cheese during aging

Ragusano cheese is a brine-salted pasta filata cheese. Composition changes during 12 mo of aging were determined. Historically, Ragusano cheese has been aged in caves at 14 to 16 degrees C with about 80 to 90% relative humidity. Cheeses (n = 132) included in our study of block-to-block variation were produced by 20 farmhouse cheese makers in the Hyblean plain region of the Province of Ragusa in Sicily. Mean initial cheese block weight was about 14 kg. The freshly formed blocks of cheese before brine salting contained about 45.35% moisture, 25.3% protein, and 25.4% fat, with a pH of 5.25. As result of the brining and aging process, a natural rind forms. After 12 mo of aging, the cheese contained about 33.6% moisture, 29.2% protein, 30.0% fat, and 4.4% salt with a pH of 5.54, but block-to-block variation was large. Both soluble nitrogen content and free fatty acid (FFA) content increased with age. The pH 4.6 acetate buffer and 12% TCA-soluble nitrogen as a percentage of total nitrogen were 16 and 10.7%, respectively, whereas the FFA content was about 643 mg/100 g of cheese at 180 d. Five blocks of cheese were selected at 180 d for a study of variation within block. Composition variation within block was large; the center had higher moisture and lower salt in moisture content than did the outside. Composition variation within blocks favored more proteolysis and softer texture in the center.     

Interaction of brine concentration, brine temperature, and presalting on salt penetration in Ragusano cheese

Thirty-one 3.6-kg blocks of Ragusano cheese were made on each of 6 different days (in different weeks) starting with a different batch of milk on each day. On d 1, 3, and 5, the cheeses were not presalted and on d 2, 4, and 6, all cheeses were presalted (PS). One of the 31 blocks of cheese was selected at random for analysis before brine salting (i.e., on d 0). The remaining 30 blocks were randomly divided into 2 groups of 15 blocks each; one group was placed in 18% brine (18%B) and the other group was placed in saturated brine (SB). For the 15 blocks within each of the 2 brine concentrations (BC), 5 blocks were placed in a brine tank at 12° C, 5 at 15° C, and 5 at 18° C, and submerged for 24 d. The research objective was to determine the combined impacts (i.e., interactions) of PS the curd before stretching, BC (SB vs. 18%B), and brine temperature (BT; 12, 15, and 18° C) on salt uptake, moisture content, and yield of Ragusano cheese. Although BC, BT, and PS each had their own separate impacts on salt uptake, there was little interaction of these effects on salt uptake when they were used in combination. The PS most quickly delivered salt to the interior of the cheese and was the most effective approach to salting for controlling early gas formation. There were strong separate impacts of BC, BT, and PS on cheese moisture content, moisture loss, and net weight loss, with BC having the largest separate impact on these parameters. Reducing BT reduced salt content and increased moisture, but the effects were small. The more important effect of reduced BT was to reduce growth of gas forming bacteria. The 18%B produced higher moisture, and less moisture and weight loss than SB. The effect of interactions of BC, BT, and PS on moisture loss and net weight loss were small. To achieve the maximum benefit from the various approaches to salting for controlling early gas formation in Ragusano cheese, PS combined with slightly lower BT (i.e., 15° C instead of 18° C) should be used. Although using 18%B instead of SB did increase salt uptake, the point at which improved salt uptake occurred due to use of 18%B did not provide benefit in prevention of early gas formation, as reported separately. However, use of 18%B instead of SB provided a 9.98% increase in cheese yield due to reduced moisture loss during brining; this would be very attractive to cheese makers. The increase in yield needs to be balanced against the risk of growth of undesirable bacteria in the 18%B and the creation of another cheese quality defect.     

Influence of brine concentration, brine temperature, and presalting on early gas defects in raw milk pasta filata cheese

Thirty-one 3.8-kg blocks of Ragusano cheese were made on each of 6 d starting with a different batch of raw milk on each day. On d 1, 3, and 5, cheeses were not presalted and on d 2, 4, and 6, all cheeses were presalted. Before brine salting, one of the 31 blocks of cheese was selected at random for analysis (i.e., at d 0). The remaining 30 blocks were randomly divided into 2 batches of 15 blocks each, one group was placed in 18% brine, and the other group was placed in saturated brine. For the 15 blocks within each of the 2 brine concentrations, 5 blocks each were placed in brine tanks at 12, 15, and 18 degrees C. Cheese blocks were sampled immediately before brine salting (d 0) and after 1, 4, 8, 16, and 24 d of brine salting. Presalting the curd with 2% added salt before stretching reduced the coliform count in the cheese by 1.41 log and resulted in a major reduction in early gas formation. Across all treatments in the present study, the average reduction in gas formation due to presalting was 75%. Reducing brine temperature had the second largest impact on reducing gas production, but did not reduce the coliform count in the cheese. Reducing brine temperature from 18 to 12 degrees C made a larger reduction in early gas formation in cheeses that were not presalted (from 6.8 to 1.8% gas holes, respectively) than in cheeses that were presalted (from 1.9 to 0.5% gas holes, respectively). To achieve the same absolute level of gas production in the nonpre-salted cheese as was achieved in presalted cheese in combination with 18 degrees C brine, the brine temperature for the nonpresalted cheese had to be lowered from 18 to 12 degrees C. Reducing brine concentration, although effective at increasing the rate of salt penetration into the block, did not have any impact on coliform count and had minimal impact on reducing gas production. The condition where reducing brine concentration was able to make a reduction in gas production was for cheeses that were not presalted and brined at 18 degrees C. Presalting is a very simple and practical approach to reducing the problem of early gas formation in combination with strategies to improve milk quality and cheese making conditions. Further work is needed to understand the impact of different levels of presalting on death of coliforms and gas production in the cheese.     

Effect of brine composition and brining temperature on cheese physical properties in Ragusano cheese

Composition and physical properties of cheeses are influenced by temperature, salt, and calcium concentration of brine. This work aimed to examine conditions of brine under which the cheese matrix contracts or expands in absence of restrictions imposed by surface rind development during overnight block formation. Three experimental 4-kg blocks of Ragusano cheese were produced at 3 different stretching temperatures (70, 80, and 90°C) and cut into pieces weighing approximately 40 to 50 g. One piece from each was chemically analyzed at time 0. All other pieces were measured for weight and volume and placed in plastic bags containing 300 mL of different brine solutions (2% NaCl with 0.1% Ca; 10% NaCl with 0, 0.1, 0.2, or 0.4% Ca; 18% NaCl with 0.1% Ca; and 26% NaCl with 0.1% Ca) at 3 different temperatures (4, 12, and 20°C). After 24h of brining, the cheeses were analyzed for weight, volume, chemical, and microstructural changes. Salt concentration in brine significantly influenced composition, weight, and volume of the cheeses after brining. Salt concentration was inversely related to cheese volume and weight. Changes in weight caused by altering the brining temperature were sufficient to reach statistical significance, and statistically significant volume changes were induced by brining temperature and its interaction with salt content. The highest volume increase (30%) occurred in the cheese stored in the 2% NaCl brine at the coldest temperature, whereas the greatest volume decrease was recorded in cheeses brined in the 26% NaCl brine. Composition was not affected by brining temperature. Calcium concentration did influence weight, volume, and composition, except on a fat-on-dry-basis. When cheeses were brined without added calcium, cheese volume and weight increased at all temperatures. At high calcium levels (0.4%), syneresis occurred and volume decreased, especially at 20°C (-16.5%). Microstructural investigation with porosity measurement confirmed weight and volume changes.     

Influence of brine concentration and temperature on composition, microstructure, and yield of feta cheese

The protein matrix of cheese undergoes changes immediately following cheesemaking in response to salting and cooling. Normally, such changes are limited by the amount of water entrapped in the cheese at the time of block formation but for brined cheeses such as feta cheese brine acts as a reservoir of additional water. Our objective was to determine the extent to which the protein matrix of cheese expands or contracts as a function of salt concentration and temperature, and whether such changes are reversible. Blocks of feta cheese made with overnight fermentation at 20 and 31°C yielded cheese of pH 4.92 and pH 4.83 with 50.8 and 48.9 g/100 g of moisture, respectively. These cheeses were then cut into 100-g pieces and placed in plastic bags containing 100 g of whey brine solutions of 6.5, 8.0, and 9.5% salt, and stored at 3, 6, 10, and 22°C for 10 d. After brining, cheese and whey were reweighed, whey volume measured, and cheese salt, moisture, and pH determined. A second set of cheeses were similarly placed in brine (n = 9) and stored for 10 d at 3°C, followed by 10 d at 22°C, followed by 10 d at 3°C, or the complementary treatments starting at 22°C. Cheese weight and whey volume (n = 3) were measured at 10, 20, and 30 d of brining. Cheese structure was examined using laser scanning confocal microscopy. Brining temperature had the greatest influence on cheese composition (except for salt content), cheese weight, and cheese volume. Salt-in-moisture content of the cheeses approached expected levels based on brine concentration and ratio of brine to cheese (i.e., 4.6, 5.7 and 6.7%). Brining at 3°C increased cheese moisture, especially for cheese with an initial pH of 4.92, producing cheese with moisture up to 58 g/100 g. Cheese weight increased after brining at 3, 6, or 10°C. Cold storage also prevented further fermentation and the pH remained constant, whereas at 22°C the pH dropped as low as pH 4.1. At 3°C, the cheese matrix expanded (20 to 30%), whereas at 22°C there was a contraction and a 13 to 18 g/100 g loss in weight. Expansion of the protein matrix at 3°C was reversed by changing to 22°C. However, contraction of the protein matrix was not reversed by changing to 3°C, and the cheese volume remained less than what it was initially.     

Salting and drying of yellowtail (Trachurus mccullochi Nichols)

Wet salting of low-fat yellowtail ( Trachurus mccullochi Nichols) using three brine solutions (15%, 21% and saturated salt) and drying of salted fish at 35°C and 50% RH, 45°C and 30% RH, or 55°C and 18% RH was carried out and assessments made of salt and moisture contents, water activity ( a_w ), and sensory properties of dried-salted fish. Brine concentration during salting and the drying conditions had a significant effect on the drying rate. Brining in saturated brine gave the most rapid rate of reduction in moisture content and the lowest final moisture content during brining, but produced a slower rate of reduction of moisture and higher final moisture content during drying. Fish brined in saturated salt and dried at 55°C was of lower sensory quality.     

Production of brine-salted Mozzarella cheese with different ratios of NaCl/KCl

Mineral and moisture concentrations, proteolysis, bacterial counts and hardness were assessed in the centre and edge portions of unmelted and melted pizza cheeses, brine-salted with four mixtures of NaCl/KCl. Bacterial counts and proteolysis were not affected by brine solutions. Moisture and Ca were lower at the edge than in centre, whereas an opposite trend was observed for Na and K. This gradient between edge and centre was different for brine solutions with KCl. After 28 d, equilibrium between the edge and the centre was obtained for moisture only. The evolution of hardness between the edge and the centre of the unmelted cheeses could mainly be attributed to the lower moisture in the edge, whereas that of the melted cheeses could be attributed to the K concentration. Further investigation is needed to understand the role that K plays in regard to all functional properties of pizza cheese brine-salted with NaCl/KCl mixtures.     

Effect of Nonuniform Cooling on Moisture,Salt, and pH Distribution in 290-Kilogram Blocks of Stirred-Curd Cheddar Cheese

Cheese samples representing six positions in each of 12 290-kg stirred curd Cheddar cheese blocks in stainless steel hoops were analyzed for salt, pH, and moisture after the blocks had been held at 6 or 22°C for 7 d after pressing. Analysis of variance was used to determine differences between vats, filling sequences, cooling treatments, and positions within cheese blocks. Temperature during cooling had a significant effect on pH, salt, and moisture distribution within the cheese. Mean differences between the centers and sides of all cheese blocks cooled at 5°C were .1% salt, .12 pH units, and 5.73% moisture. Differences between the centers and sides of cheese blocks cooled at 22°C were 0% salt, .03 pH units, and .96% moisture. After filling the hoops, moisture transferred from high temperature to low temperature areas in the cheese. Moisture differences in large cheese blocks were minimized when temperature differences within blocks were reduced.     

Influence of salting procedure on the composition of Muenster-type cheese

Muenster-type cheeses were salted with a traditional saturated brine solution or by direct addition of salt to the curd. Cheeses were evaluated at 0, 30, 60, 90, 120, and 180 d of age for numbers and type of microflora, casein hydrolysis, and amounts of free fatty acids. No significant differences were found in the populations of starter, lactobacilli, or yeast for the brine- and direct-salted cheeses. The amounts of free fatty acids liberated were similar for both cheeses. The hydrolysis of alpha s1-casein was complete at 90 d of age, whereas only 40% of the beta-casein was hydrolyzed at 180 d of age. The inner layer of the brine-salted cheeses had the highest number of starter microorganisms, followed by the middle and outer layers, respectively. The salt concentrations were similar in the three layers after 4 mo of age. Results of this study showed that comparable Muenster-type cheese could be produced with either of the salting procedures. With direct salt addition to curd, a 59% reduction was observed in salt emissions from the Muenster manufacturing process.     

Monitoring the chemical and textural changes during ripening of Iranian White cheese made with different concentrations of starter

The effect of the concentration of starter inoculated to milk on the composition, free tyrosine-tryptophan content, microstructure, opacity, and fracture stress of Iranian White cheese (IWC) was studied during 50 d of ripening in brine. Three treatments of cheese were made using 1-fold (IWC1S), 2-fold (IWC2S), and 4-fold (IWC4S) concentrations of a direct-to-vat mesophilic mixed culture containing Lactococcus lactis ssp. cremoris and Lactococcus lactis ssp. lactis as starter. As ripening progressed, moisture and protein contents of the treatments continuously decreased, whereas their total ash, salt, and salt in moisture contents increased. Fat content and pH of cheeses remained stable during ripening. The pH of cheese milk at the time of renneting, which decreased by increasing the concentration of starter (6.57, 6.49, and 6.29 for IWC1S, IWC2S, and IWC4S, respectively), significantly affected most of the chemical characteristics and opacity of cheese. Lower pH values at renneting decreased moisture and ash contents, whereas cheese protein content increased. The concentration of free tyrosine-tryptophan in curd increased at first 29 d but decreased between d 29 and 49 of aging. The changes observed in cheese whiteness followed the changes in moisture content of the treatments. As the concentration of starter inoculated to milk increased, the value of fracture stress at a given ripening time significantly decreased, leading to a less resistant body against applied stress. A similar trend was also observed for fracture strain during cheese ripening. The micrographs taken by scanning electron microscopy provided a meaningful explanation for decrease in the value of fracture stress. As the cheese ripening progressed or the concentration of starter increased, the surface area occupied by the protein fraction in cheese microstructure decreased, leading the way to lower the force-bearing component in cheese texture.     

A multi-component approach to salt and water diffusion in cheese

A theoretically based model was developed using the Maxwell–Stefan equation to predict the salt gain and moisture loss of cheese during brine salting. The model was used to predict changes in the salt and moisture profile, and dimensions of the cheese. The best solutions were obtained when the diffusivities were made functions of porosity and salt concentration. For Gouda cheese the predicted moisture and salt/moisture profiles were within 0.6% moisture and 0.3% salt/moisture of published experimental data. The model predicted an overall gain in salt of 1.55% by weight, an overall reduction in moisture from 43.4 to 41.0%, a mass loss of 1.5% and a volume reduction of 2.6% after 8 days of brining.     

Effect of salt on structure-function relationships of cheese

Our objective was to determine the effect of salt on structural and functional properties of cheese. Unsalted Muenster cheese was obtained on 1 d, vacuum packaged, and stored for 10 d at 4 degrees C. The cheese was then cut into blocks that were vacuum packaged. After 4 d of storage at 4 degrees C, cheese blocks were high-pressure injected one, three, or five times, with a 20% (wt/wt) sodium chloride solution. Successive injections were performed 24 h apart. After 40 d of storage at 4 degrees C, cheese blocks were analyzed for chemical, structural, and functional attributes. Injecting sodium chloride increased the salt content of cheese, from 0.1% in the control, uninjected cheese to 2.7% after five injections. At the highest levels, salt injection promoted syneresis, and, after five injections, the moisture content of cheese decreased from 41 to 38%. However, the increased salt content caused a net weight gain. Cheese pH, soluble nitrogen, and total and soluble calcium content were unaffected. Cheese injected five times had a 4% increased area of cheese occupied by protein matrix compared with uninjected cheese. Hardness, adhesiveness, and initial rate of cheese flow increased, and cohesiveness decreased upon salt injection. However, the final extent of cheese flow, or melting was unaffected. We concluded that adding salt to cheese alters protein interactions, such that the protein matrix becomes more hydrated and expands. However, increasing the salt content of cheese did not cause an exchange of calcium with sodium. Therefore, calcium-mediated protein interactions remain a major factor controlling cheese functionality.     

Fate of Aflatoxin M1 during Manufacture and Storage of Feta Cheese

ABSTRACT:  The effect of feta cheese manufacture on aflatoxin M₁ (AFM₁) content was studied using an enzyme immunoassay technique. Feta cheese was made from milk spiked with 1 and 2 μg AFM₁ per kilogram milk. Pasteurization at 63 °C for 30 min caused <10% destruction of AFM₁. During cheese making, the remaining AFM₁ in milk was partitioned between curd and whey with two-thirds retained in the curd and one-third going into the whey. Cheeses were then stored for 2 mo in 8%, 10%, and 12% brine solutions at 6 and 18 °C. There was a 22% to 27% reduction of AFM₁ during the first 10 d of storage, with slightly more loss as salt concentration increased and when the cheese was stored at 18 °C. Further storage caused only slight decrease in AFM₁ and after 30 d of brining there was no difference in AFM₁ content of the cheese based upon salt concentration of the brine. At 18 °C, no further losses of AFM₁ occurred after 30 d, and at 6 °C, there was continued slight decrease in AFM₁ levels until 50 d. After 60 d of brining, there was a total loss of 25% and 29% of the AFM₁ originally present for cheese brined at 6 and 18 °C, respectively. Thus, the combination of pasteurization, conversion of milk into feta cheese, and at least 50 d storage of cheese in brine caused a total loss of about 50% of the AFM₁ originally present in the raw milk.     

Effects of salting method and storage time on composition and quality of feta cheese

Feta cheese was manufactured by using five different salting methods (dry salting for one day followed by addition of 6% NaCl brine, dry salting for 1,2 or 3 days followed by addition of 7% NaCl brine and dry salting for 3 days followed by addition of 8% NaCl brine). The effects of salting method and storage time on the composition, physicochemical, organoleptic and rheological properties of feta cheese were studied. It was found that moisture was not affected by salting method or storage time. The salting method but not the storage time had a significant effect on salt content. As the salt content of cheeses increased or the storage time was prolonged the moisture decreased. pH and cheese yield were not influenced by salting method but did decrease with storage time. Protein content was not affected by salting method or storage time, whereas fat content was affected by both factors. Proteolysis, lipolysis, organoleptic and rheological properties of cheeses were not influenced by the salting methods applied. On the other hand, storage time had a significant effect on proteolysis, lipolysis, cheese appearance, fracturability and percentage compression at the yield point. Dry salting of cheese for one day and preservation in 7% NaCl brine was considered as the most appropriate salting method for practical application.     

Hot Brine Stretching and Molding of Low Moisture Mozzarella Cheese Made from Retentate-Supplemented Milks

Low moisture Mozzarella cheese curd was made from cheese milks supplemented to 1.2:1 and 1.4:1 fat and protein with 4.5:1 retentates of ultrafiltration stretched and molded in hot 10% brine.Retentate supplementation improved cheese yield and yield efficiencies. Retentate-supplemented cheese had higher protein and fat and lower moisture than controls. Maximum total solids and yields were obtained from cheese stretched in hot brine. Such cheese showed more uniform salt distribution but slightly lower salt concentration than controls. More loss of fat occurred in whey in control cheese stretched in hot water. Hot brine stretching of low moisture Mozzarella cheese made from retentate-supplemented milk suggests savings in time, space, equipment, and labor without detrimental effects on cheese color and meltability.     

Influence of milk centrifugation, brining and ripening conditions in preventing gas formation by Clostridium spp. in Gouda cheese

This study examined milk centrifugation, increased salt concentration, and low ripening temperature as potential strategies to prevent late blowing caused by gas-forming Clostridium spp. in Gouda cheese. The survival of clostridia spores in cheese brine and their ability to enter Gouda cheese during brining was also evaluated. Centrifugation (3000 x g for 30 s) of contaminated milk resulted in > 60% spore reduction, with increased spore reduction at greater centrifugal forces. Low levels of C. tyrobutyricum and C. sporogenes spores survived in saturated (23%, w/v) brine with 2% (v/v) added whey at 15 degrees C for 63 days, while C. beijerinckii and C. butyricum spores were not detectable on days 4 and 35, respectively. Spores of C. tyrobutyricum in brine infiltrated Gouda cheese during 2 h of brining at 13 degrees C resulted in production of small gas holes during ripening. In Gouda cheese slurry stored at 13 degrees C, three C. tyrobutyricum strains plus one of three C. sporogenes strains germinated in the slurry with no added salt. Of three C. tyrobutyricum strains stored at 13 degrees C in slurries with higher water-phase salt concentrations of 2.4 and 3.6%, two strains and one strain germinated, respectively. No germination of spores was detected in any cheese slurry stored at 5 or 8 degrees C. Milk centrifugation, increased percent water-phase salt, absence of spores in brine, and decreased ripening temperature are all potentially important measures against gas production by Clostridium spp. in Gouda cheese.     

The effect of sodium chloride substitution with potassium chloride on texture profile and microstructure of Halloumi cheese

The effect of partial substitution of NaCl with KCl on texture profile and microstructure of Halloumi cheese was investigated. Four batches of Halloumi cheese were made and kept in 4 different brine solutions (18%, wt/wt), including A) NaCl only, B) 3NaCl:1KCl, C) 1NaCl:1KCl, and D) 1NaCl:3KCl and then stored at 4°C for 56 d. The texture profile was analyzed using an Instron universal machine, whereas an environmental scanning electron microscope was used to investigate the effect of NaCl substitution on the microstructure of cheeses. No significant difference was found in hardness, cohesiveness, adhesiveness, and gumminess among experimental cheeses at the same storage day. Hardness, cohesiveness, and gumminess decreased significantly during storage period with the same salt treatment, whereas adhesiveness significantly increased. Environmental scanning electron microscope micrographs showed a compact and closed texture for cheeses at the same storage period. The microstructure of all cheeses became more closed and compact with storage period. Calcium content negatively correlated with hardness and Na and K contents during storage with the same salt treatment.