Effect of liquid whey protein concentrate-based edible coating enriched with cinnamon carbon dioxide extract on the quality and shelf life of Eastern European curd cheese.

Fresh unripened curd cheese has long been a well-known Eastern European artisanal dairy product; however, due to possible cross-contamination from manual production steps, high moisture content (50-60%), and metabolic activity of present lactic acid bacteria, the shelf life of curd cheese is short (10-20 d). Therefore, the aim of this study was to improve the shelf life of Eastern European acid-curd cheese by applying an antimicrobial protein-based (5%, wt/wt) edible coating. The bioactive edible coating was produced from liquid whey protein concentrate (a cheese production byproduct) and fortified with 0.3% (wt/wt, solution basis) Chinese cinnamon bark (Cinnamomum cassia) CO2 extract. The effect of coating on the cheese was evaluated within package-free (group 1) and additionally vacuum packaged (group 2) conditions to represent types of cheeses sold by small and big scale manufacturers. The cheese samples were examined over 31 d of storage for changes of microbiological (total bacterial count, lactic acid bacteria, yeasts and molds, coliforms, enterobacteria, Staphylococcus spp.), physicochemical (pH, lactic acid, protein, fat, moisture, color change, rheological, and sensory properties). The controlled experiment revealed that in group 1, applied coating affected appearance and color by preserving moisture and decreasing growth of yeasts and molds during prolonged package-free cheese storage. In group 2, coating did not affect moisture, color, or texture, but had a strong antimicrobial effect, decreasing the counts of yeasts and molds by 0.79 to 1.55 log cfu/g during 31 d of storage. In both groups, coating had no effect on pH, lactic acid, protein, and fat contents. Evaluated sensory properties (appearance, odor, taste, texture, and overall acceptability) of all samples were similar, indicating no effect of the coating on the flavor of curd cheese. The edible coating based on liquid whey protein concentrate with the incorporation of cinnamon extract was demonstrated to efficiently extend the shelf life of perishable fresh curd cheese, enhance its functional value, and contribute to a more sustainable production process.

Active edible furcellaran/whey protein films with yerba mate and white tea extracts: Preparation, characterization and its application to fresh soft rennet-curd cheese.

Biopolymer films based on furcellaran-whey protein isolate (FUR/WPI) and furcellaran-whey protein isolate incorporated with yerba mate extract (FUR/WPI + YM) and with white tea extract (FUR/WPI + WT) were successfully developed and investigated as active packaging materials for fresh soft rennet-curd cheese. YM improved water vapour permeability, water content, solubility, modulus elasticity, puncture strength and thermal stability of film. Water content and water activity decreased (P ≤ .05) during storage in cheese packed in each kind of the biopolymer films. These parameters did not change (P > .05) in control wrapped in linear low-density polyethylene (LLDPE). Likewise, pH decreased with the exception of the application of LLDPE and FUR/WPI + YM. In those cheese samples pH did not differ (P > .05) during storage. Total bacteria count decreased (P ≤ .05) in the cheese samples wrapped in edible films during storage. However, their levels were not significantly lower than control samples when compared within the storage week. The yeast and mould counts did not differ (P > .05) during storage for the cheese packed in FUR/WPI + WT, whereas it increased in other cheese samples. The coliform bacteria count decreased (P ≤ .05) during storage in all examined cheese samples. Overall organoleptic quality was more often rated as desirable and very desirable in cheese packed in edible films than in LLDPE.

Effect of microencapsulated ferrous sulfate particle size on Cheddar cheese composition and quality.

Iron-fortified Cheddar cheese was manufactured with large microencapsulated ferrous sulfate (LMFS; 700-1,000 µm in diameter) or small microencapsulated ferrous sulfate (SMFS; 220-422 µm in diameter). Cheeses were aged 90 d. Compositional, chemical, and sensory characteristics were compared with control cheeses, which had no ferrous sulfate added. Compositional analysis included fat, protein, ash, moisture, as well as divalent cations iron, calcium, magnesium, and zinc. Thiobarbituric acid reactive species assay was conducted to determine lipid oxidation. A consumer panel consisting of 101 participants evaluated the cheeses for flavor, texture, appearance, and overall acceptability using a 9-point hedonic scale. Results showed 66.0% iron recovery for LMFS and 91.0% iron recovery for SMFS. Iron content was significantly increased from 0.030 mg of Fe/g in control cheeses to 0.134 mg of Fe/g of cheese for LMFS and 0.174 mg of Fe/g of cheese for SMFS. Fat, protein, ash, moisture, magnesium, zinc, and calcium contents were not significantly different when comparing iron-fortified cheeses with the control. Iron fortification did not increase lipid oxidation; however, iron fortification negatively affected Cheddar cheese sensory attributes, particularly the LMFS fortified cheese. Microencapsulation of ferrous sulfate failed to mask iron's distinct taste, color, and odor. Overall, SMFS showed better results compared with LMFS for iron retention and sensory evaluation in Cheddar cheese. Results of this study show that size of the microencapsulated particle is important in the retention of the iron in the cheese and its sensory attributes. This study provides new information on the importance of particle size with microencapsulated nutrients.

Short communication: Physicochemical and antioxidant properties of Cheddar-type cheese fortified with Inula britannica extract.

Cheddar-type cheese was fortified with the antioxidant Inula britannica flower extract (IBE). Cheddar-type cheeses manufactured with varying concentrations of IBE (0, 0.25, 0.5, 0.75, and 1% wt/vol) were analyzed during storage at 4°C, 0, 1, 2, and 3 wk after production. Higher IBE concentrations resulted in higher protein and ash contents, with a concomitant decrease in pH, total solid, and fat content relative to the unfortified control cheese. The total phenolic content also increased with IBE concentration, but decreased over longer storage periods. The antioxidant activities of the cheeses, determined as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and ferric thiocyanate assay results, increased proportionally to the total phenolic content. The highest antioxidant effect was observed in the 1% IBE-fortified cheese, showing 79 and 86% antioxidant effects in the DPPH and ferric thiocyanate assays, respectively. At the 1-wk time point, the 5 cheese preparations underwent sensory evaluation for odor, taste, texture, color, and overall quality, determined using a descriptive analysis by a trained panel (n=20). The addition of IBE resulted in some increases in extract odor and taste. Overall, IBE showed good potential as an antioxidant supplement for dairy products.

Effect of feeding goats with distilled and non-distilled thyme leaves (Thymus zygis subp. gracilis) on milk and cheese properties.

The aim of this study was to evaluate the effect of feeding goats with distilled and non-distilled thyme leaves (Thymus zygis subsp. gracilis) on the physicochemical composition and technological properties of pasteurised goat milk, and on the physicochemical composition, phenolic content, oxidative stability, microbiology, sensory and texture profile of Murcia al Vino goat cheese. One group of goats was fed the basal diet (control), the second and third groups were fed with different levels of distilled (10 and 20%) or non-distilled (3·75 and 7·5%) thyme leaves. Goat milk physicochemical composition was significantly affected by the substitution of 7·5% of basal goat diet with non-distilled thyme leaves (increase in fat, protein, dry matter and PUFA content), while goat milk clotting time was increased significantly by the introduction of 20% distilled thyme leaves, which reduces its technological suitability. Microbiology, sensory and texture profiles were not affected by the introduction of distilled thyme leaves. The introduction of distilled and non-distilled thyme leaves as an alternative feed to diet can lead to an inhibition of lipids oxidation. The introduction of distilled and non-distilled thyme leaves into goat's diet can be successfully adopted as a strategy to reduce feeding costs and to take advantage of the waste from the production of essential oils, minimising waste removing costs and the environmental impact.

The influence of alkaline earth metal equilibria on the rheological, melting and textural properties of Cheddar cheese.

The total calcium content of cheese, along with changes in the equilibrium between soluble and casein (CN)-bound calcium during ripening can have a major impact on its rheological, functional and textural properties; however, little is known about the effect of other alkaline earth metals. NaCl was partially substituted with MgCl2 or SrCl2 (8·7 and 11·4 g/kg curd, respectively) at the salting stage of cheesemaking to study their effects on cheese. Three cheeses were produced: Mg supplemented (+Mg), Sr supplemented (+Sr) and a control Cheddar cheese. Ca, Mg and Sr contents of cheese and expressible serum obtained therefrom were determined by atomic absorption spectroscopy. Addition of Mg2+ or Sr2+ had no effect on % moisture, protein, fat and extent of proteolysis. A proportion of the added Mg2+ and Sr2+ became CN-bound. The level of CN-bound Mg was higher in the +Mg cheese than the control throughout ripening. The level of CN-bound Ca and Mg decreased during ripening in all cheeses, as did % CN-bound Sr in the +Sr cheese. The presence of Sr2+ increased % CN-bound Ca and Mg at a number of ripening times. Adding Mg2+ had no effect on % CN-bound Ca. The +Sr cheese exhibited a higher G' at 70 °C and a lower LTmax than the control and +Mg cheeses throughout ripening. The +Sr cheese had significantly lower meltability compared with the control and +Mg cheeses after 2 months of ripening. Hardness values of the +Sr cheese were higher at week 2 than the +Mg and control cheeses. Addition of Mg2+ did not influence the physical properties of cheese. Supplementing cheese with Sr appeared to have effects analogous to those previously reported for increasing Ca content. Sr2+ may form and/or modify nanocluster crosslinks causing an increase in the strength of the para-casein matrix.

Composition and textural properties of Mozzarella cheese naturally-enriched in polyunsaturated fatty acids.

The effects of adding flaxseed or fish oil to the diet of dairy cows on the chemical and physical profile of Mozzarella cheese production were studied. The experiment involved 24 Friesian cows, divided into 3 groups accordingly fat supplementation: basal diet (CT), diet supplemented with flaxseed (FS) or fish oil (FO). Mozzarella cheeses were manufactured from bulk milk of each group. Bulk milk was analysed for chemical composition and renneting parameters. Mozzarella cheeses were analysed for chemical composition, fatty acid profile, and textural properties. Results suggest that Mozzarella cheese from cows receiving flaxseed supplementation showed a decrease in saturated fatty acids (SFA), an increase in monounsaturated fatty acids (MUFA), and in polyunsaturated fatty acids (PUFA) compared with control Mozzarella cheese. The increased dietary intake of C18:3 in flaxseed supplemented cows resulted in increased levels of trans-11 C18:1, and of CLA cis-9 trans-11 C18:2, and in low Atherogenic and Trombogenic Indexes. FO Mozzarella cheese showed compositional and textural properties quite similar to CT Mozzarella cheese; however, increased levels of n-3 polyunsaturated fatty acids in FO Mozzarella were found.

Effect of flaxseed supplementation rate and processing on the production, fatty acid profile, and texture of milk, butter, and cheese.

Health and nutrition professionals advise consumers to limit consumption of saturated fatty acids and increase the consumption of foods rich in n-3 fatty acids. Researchers have previously reported that feeding extruded flaxseed, which is high in C18:3n-3, improves the fatty acid profile of milk and dairy products to less saturated fatty acids and to more C18:3n-3. Fat concentrations in milk and butter decreased when cows were fed higher concentrations of extruded flaxseed. The objective of this study was to determine the optimal rate of flaxseed supplementation for improving the fatty acid profile without decreasing production characteristics of milk and dairy products. By using a double 5 × 5 Latin square design, 10 mid- to late-lactation Holstein cows were fed extruded (0, 0.91, 1.81, and 2.72 kg/d) and ground (1.81 kg/d) flaxseed as a top dressing for 2-wk periods each. At the end of each 2-wk treatment period, milk and serum samples were taken. Milk was subsequently manufactured into butter and fresh Mozzarella cheese. Increasing supplementation rates of extruded flaxseed improved the fatty acid profile of milk, butter, and cheese gradually to less saturated and atherogenic fatty acids and to more C18:3n-3 by increasing concentrations of C18:3n-3 in serum. The less saturated fatty acid profile was associated with decreased hardness and adhesiveness of refrigerated butter, which likely cause improved spreadability. Supplementation rates of extruded flaxseed did not affect dry matter intake of the total mixed ration, milk composition, and production of milk, butter, or cheese. Flaxseed processing did not affect production, fatty acid profile of milk, or texture of butter and cheese. Feeding up to 2.72 kg/d of extruded flaxseed to mid- to late-lactation Holstein cows may improve nutritional and functional properties of milk fat without compromising production parameters.

Does milk treatment before cheesemaking affect microbial and chemical traits of ripened cheese? Grana Trentino as a case study.

The aim of this study was to evaluate the influence of different storage temperatures and delivery system of the milk on the microbiological and physicochemical characteristics of Grana Trentino, a long-ripened hard-cooked Italian cheese. In particular, 3 kinds of milk storage and delivery were studied: milk delivered to the dairy in the traditional manner without temperature control, milk delivered at 18°C, and milk stored at the farm and delivered at 12°C. Milk, natural whey starter, and cheeses after 18 mo of ripening were sampled for microbiological profiles, physicochemical analysis, and proteolysis evaluation, and a study of cheese volatile compounds through a solid-phase microextraction gas chromatography-mass spectrometry technique was performed. Milk microbiota was not affected by any of the treatments. At the end of ripening, free fatty acid and ester contents were significantly higher in cheeses from milk without temperature control. This was probably due to the milk delivery to the dairy in churns causing the fat globule membrane break during transport and, consequently, a greater release of fat and deeper lipolysis. Milk refrigeration at 12°C for 12h before delivery affected the distribution of nitrogen fractions in cheeses. Lower temperatures of milk storage favored a larger soluble nitrogen fraction and greater cheese proteolysis, probably caused by an enhanced plasmin activity. From this work, it is concluded that both milk temperature storage and transport system could affect cheese ripening, leading to significant differences in chemical compounds: if milk was delivered by churns, higher free fatty acid and ester content in cheeses was observed; if milk was stored at 12°C for 12h before delivery, greater cheese proteolysis was induced with consequent faster ripening.

Effect of zinc fortification on Cheddar cheese quality.

Zinc-fortified Cheddar cheese containing 228 mg of zinc/kg of cheese was manufactured from milk that had 16 mg/kg food-grade zinc sulfate added. Cheeses were aged for 2 mo. Culture activity during cheese making and ripening, and compositional, chemical, texture, and sensory characteristics were compared with control cheese with no zinc sulfate added to the cheese milk. Compositional analysis included fat, protein, ash, moisture, zinc, and calcium determinations. The thiobarbituric acid (TBA) assay was conducted to determine lipid oxidation during aging. Texture was analyzed by a texture analyzer. An untrained consumer panel of 60 subjects evaluated the cheeses for hardness, off-flavors, appearance, and overall preference using a 9-point hedonic scale. Almost 100% of the zinc added to cheese milk was recovered in the zinc-fortified cheese. Zinc-fortified Cheddar cheese had 5 times more zinc compared with control cheese. Zinc-fortified cheese had higher protein and slightly higher fat and ash contents, whereas moisture was similar for both cheeses. Zinc fortification did not affect culture activity during cheese making or during the 2-mo aging period. The TBA value of control cheese was higher than that of zinc-fortified cheese at the end of ripening. Although zinc-fortified cheese was harder as determined by the texture analyzer, the untrained consumer panel did not detect differences in the sensory attributes and overall quality of the cheeses. Fortification of 16 mg/kg zinc sulfate in cheese milk is a suitable approach to fortifying Cheddar cheese without changing the quality of Cheddar cheese.

Survival of Listeria monocytogenes, and other food spoilage microbes in vacuum packaged West African soft cheese 'wara'.

'Wara' soft cheese is traditionally produced in Nigeria and has a poor microbial quality. This study assessed the survivability of Listeria monocytogenes and other food spoilage microbes (enterobacteriacea, molds and yeasts) in vacuum packaged soft cheese treated independently with Carica papaya (Vcpc), Terminalia cattapa (Vtcc) crude extracts, nisin (Vnc), and the combination of these three treatments (V+3) stored at 15 degrees C and 28 degrees C for a three week storage period. Vacuum packaging did not suppress Listeria monocytogenes, and there were no significant differences in the L. monocytogenes counts throughout the storage weeks (P > 0.05). The enterobacteriacea counts were suppressed to undetectable levels at 15 degrees C storage temperature by the third week of storage in all treatments except the Vnc and V+3. Molds and yeasts were undetectable in all treatments throughout the storage weeks. Significant differences occurred in the microbial count at the two storage temperatures and storage weeks (P < 0.05). It can therefore be concluded from this work that Vacuum packaging and addition of crude extracts (Carica papaya, Terminalia cattapa) in soft cheese storage can suppress enterobacteriacea, molds and yeasts. Food technologists developing industrialized 'wara should consider including these extracts and vacuum packaging in their production. Therefore, their use in extension of the shelf-life of soft cheese is recommended.

The role of copper in the manufacture of Finnish Emmental cheese.

The effects of added copper in the manufacture of Finnish Emmental cheese were studied. Consequently, cheeses were produced with or without the copper supplement and a facultative heterofermentative strain, Lactobacillus rhamnosus Lc705, which is currently utilized as a protective culture in large-scale manufacture in Finland. Cheeses were examined at 1, 7, 30, 60, and 90 d from the microbiological, chemical, and sensory points of view. Organic acid production was affected by the presence of copper in the cheeses. The addition of copper to cheesemilk increased the level of primary proteolysis and slowed secondary proteolysis as measured by nitrogen content in different extracts after citrate fractionation of cheeses, in pH 4.4-soluble nitrogen and 5% phosphotungstic acid-soluble nitrogen, respectively. The presence of copper appears to positively regulate the sensory characteristics of the cheese produced in our conditions; in particular, consistency was affected significantly. The role of the Lb. rhamnosus Lc705 protective strain has not been shown to have important effects on most of the parameters that influence the final quality of the cheeses. Although the traditional plating systems for revealing bacterial populations during cheese manufacture did not reveal any drastic differences caused by the presence of copper, the results from chemical and sensory analyses suggest that its use plays a significant role in the regulation of bacterial physiological and biochemical activities, which in turn affect the sensory quality of Emmental cheese.

The effect of substitution of NaCl with KCl on chemical composition and functional properties of low-moisture Mozzarella cheese.

The effect of NaCl substitution with KCl on chemical composition, organic acids profile, soluble calcium, and functionality of low-moisture Mozzarella cheese (LMMC) was investigated. Functionality (meltability and browning), organic acids profile, and chemical composition were determined. Chemical composition showed no significant difference between experimental cheeses at same storage period, and same salt treatment. Meltability of LMMC salted with 3NaCl:1KCl, 1NaCl:1KCl, and 1NaCl:3KCl was higher compared with only NaCl (control). The amount of soluble Ca and P increased significantly during storage, with no significant difference between salt treatments. Organic acids profile did not differ between salt treatments at the same storage time.

Effects of copper on germination, growth and sporulation of Clostridium tyrobutyricum.

The effects of copper (Cu(2+)) on spore germination, vegetative growth and sporulation of Clostridium tyrobutyricum, which is capable to causing texture and flavour defects in Emmental cheese, were studied. Spore suspensions of three different strains were used as starting material for two experimental set-ups. The first studied the effects of supplemented (0-30 ppm) copper in RCM medium during spore germination and vegetative growth of C. tyrobutyricum measured by plating. The second set-up studied the effects of copper (0-30 ppm) in RCM medium during growth and sporulation of C. tyrobutyricum as measured by optical density at 550 nm and by platings after heat treatment of the samples respectively. Inhibition of germination, vegetative growth and sporulation processes by copper was strain-dependent. Both sporulation and germination were more sensitive than vegetative growth of C. tyrobutyricum to the inhibitory effects of copper. Copper, at the concentrations investigated in this study, inhibits spore germination of C. tyrobutyricum strains. Consequently copper may reduce the risk of late blowing spoilage from in the germination of C. tyrobutyricum spores during the ripening period of Emmental cheese.

[Experimental rationale for approaches to the development and evaluation of new functional foodstuffs].

This comprehensive experimental study had the objective to determine the optimum ratio of calcium and vitamin D used as additives in food compositions and provide an experimentally-based rationale for the use of new functional dairy products and evaluation of their nutritional value. Experimental medico-biological assessment was conducted using growing male Wistar rats by balance and biochemical methods. It was shown that the calcium/vitamin D ratio in foodstuffs determines their functional efficiency. High nutritive and biological value was documented for some new cottage cheese products rich in calcium (240 mg%) and vitamin D (1 mg%). Results of the study were used to develop guidelines for the enrichment of various food compositions with calcium and vitamin D and substantiate methods for the assessment of their real functional effectiveness.

Effects of extruded linseed supplementation on n-3 fatty acids and conjugated linoleic acid in milk and cheese from ewes.

The objective of this study was to assess the effects of dietary supplementation of extruded linseed on animal performance and fatty acid (FA) profile of ewe milk for the production of n-3 FA- and conjugated linoleic acid-enriched cheeses. A Manchega ewe flock (300 animals) receiving a 60:40 forage:concentrate diet was divided into 3 groups supplemented with 0, 6, and 12 g of extruded linseed/100 g of dry matter for the control, low, and high extruded linseed diets, respectively. Bulk and individual milk samples from 5 dairy ewes per group were monitored at 7, 14, 28, 45, and 60 d following supplementation. Manchego cheeses were made with bulk milk from the 3 treatment groups. Milk yield increased in dairy ewes receiving extruded linseed. Milk protein, fat, and total solids contents were not affected by linseed supplementation. Milk contents of alpha-linolenic acid increased from 0.36 with the control diet to 1.91% total FA with the high extruded linseed diet. Similarly, cis-9 trans-11 C18:2 rose from 0.73 to 2.33% and its precursor in the mammary gland, trans-11 C18:1, increased from 1.55 to 5.76% of total FA. This pattern occurred with no significant modification of the levels of trans-10 C18:1 and trans-10 cis-12 C18:2 FA. Furthermore, the high extruded linseed diet reduced C12:0 (-30%), C14:0 (-15%) and C16:0 (-28%), thus significantly diminishing the atherogenicity index of milk. The response to linseed supplementation was persistently maintained during the entire study. Acceptability attributes of n-3-enriched versus control cheeses ripened for 3 mo were not affected. Therefore, extruded linseed supplementation seems a plausible strategy to improve animal performance and nutritional quality of dairy lipids in milk and cheese from ewes.

Short communication: Effects of milk fat depression induced by a dietary supplement containing trans-10, cis-12 conjugated linoleic acid on properties of semi-hard goat cheese.

Dietary supplements of conjugated linoleic acid (CLA) containing trans-10, cis-12 CLA reduce milk fat synthesis in lactating goats. This study investigated effects of milk fat depression induced by dietary CLA supplements on the properties of semi-hard goat cheese. Thirty Alpine does were randomly assigned to 1 of 3 groups and fed diets with lipid-encapsulated CLA that provided trans-10, cis-12 CLA at 0 (control), 3 (CLA-1), and 6 g/d (CLA-2). The experiment was a 3 x 3 Latin square design. Periods were 2 wk in length, each separated by 2-wk periods without CLA supplements. Bulk milk was collected on d 3 and 13 of each of 3 periods for cheese manufacture. The largest decrease (23.2%) in milk fat content, induced by the high dosage (6 g/d per doe) of trans-10, cis-12 CLA supplementation at d 13 of treatment, resulted in decreases of cheese yield and moisture of 10.2 and 10.0%, respectively. Although CLA supplementation increased the hardness, springiness, and chewiness, and decreased the cohesiveness and adhesiveness of cheeses, no obvious defects were detected and no significant differences were found in sensory scores among cheeses. In conclusion, milk fat depression induced by a dietary CLA supplement containing trans-10, cis-12 CLA resulted in changes of fat-to-protein ratio in cheese milk and consequently affected properties of semi-hard goat cheese.

Fortification of reduced-fat Cheddar cheese with n-3 fatty acids: effect on off-flavor generation.

The objective of this study was to fortify 50% reduced fat Cheddar cheese with n-3 fatty acids and evaluate whether this fortification generated specific off-flavors in the cheese. Docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids were added to the cheese to obtain 3 final fortification levels [18, 35, and 71 mg of DHA/EPA per serving size (28 g) of cheese] representing 10, 20, and 40% of the suggested daily intake level for DHA/EPA. The presence of oxidized, rancid, and fishy flavors as a function of fortification level and cheese aging (6 mo) was evaluated using a sensory descriptive panel. No differences were found in the oxidized and rancid flavors as a consequence of DHA/EPA fortification, with only slight intensities of these flavors. The presence of fishy off-flavor was dependent on the fortification level. Cheeses with low fortification levels (18 and 35 mg of DHA/EPA per serving size) did not develop significant fishy off-flavor compared with the control, whereas at the highest fortification level (71 mg of DHA/EPA per serving size) the fishy off-flavor was significantly stronger in young cheeses. The fishy flavor decreased as a function of age and became nonsignificant compared with the control at 3 mo of storage. Even though fishy flavors were detected in the fortified cheeses, the DHA/EPA content during storage remained constant and complied with the suggested values for food fortification. Results obtained from this research indicate that 50% reduced-fat Cheddar cheese aged for 3 mo can be used as a vehicle for delivery of n-3 fatty acids without generation of off-flavors.

Effect of mesophilic lactobacilli and enterococci adjunct cultures on the final characteristics of a microfiltered milk Swiss-type cheese.

The effect of four associations of adjunct cultures composed of mesophilic lactobacilli and enterococci, either solely or combined, on the microbiological, biochemical and sensory characteristics of Swiss-type cheese made using microfiltered cows' milk and supplemented with propionibacteria was studied. The global pattern of growth was similar to that generally observed in raw milk cheese and interactions between microflora were highlighted during ripening. Enterococci, which negatively affected the survival of streptococci starters, seemed to play a limited role in the formation of volatile compounds, probably due to their low levels throughout ripening. On the contrary, mesophilic lactobacilli, which affected the evolution of propionibacteria, enterococci and L. delbrueckii subsp. lactis starter counts, modified free amino acid content, production of volatile compounds and organoleptic properties of mature cheese. This population appeared to be of major importance in the formation of cheese flavor as it was positively related to numerous potential flavor compounds such as alcohols and their corresponding esters, acetaldehyde and 4-methyl-4-heptanone. The original mesophilic lactobacilli present in milk could play an important role in the sensorial diversity of raw milk Swiss-type cheeses such as Comte.

Effects of natural compounds on microbial safety and sensory quality of Fior di Latte cheese, a typical Italian cheese.

This work presents a preliminary study to assess the efficiency of plant essential oils as natural food preservatives in Fior di Latte cheese. Selected compounds were directly dissolved into Fior di Latte brine. Packaged Fior di Latte samples were stored at 10 degrees C for about 6 d. The cell loads of spoilage and useful microorganisms were monitored to calculate the microbial acceptability limit. Results show that some tested compounds were not acceptable by the panel from a sensorial point of view. Most compounds did not affect the microbial acceptability limit value to a great extent, and only a few such as lemon, sage, and thyme markedly prolonged the microbial acceptability limit of the investigated fresh cheese. Moreover, the above active agents exerted an inhibitory effect on the microorganisms responsible for spoilage without affecting the dairy microflora.