Consumer perception of Cheddar cheese color.

The color of Cheddar cheese in the United States is influenced by many factors, primarily the amount of annatto added as a colorant. The US Food and Drug Administration is currently reviewing its definition of the term "natural" on food labels, which may result in the use of colorants being restricted in natural cheeses. The objective of this study was to evaluate how consumers perceive Cheddar cheese color to better understand how changes to legislation surrounding colorants in natural Cheddar cheese may affect consumption. We were also interested in determining if a relationship exists between color and other perceived characteristics of Cheddar cheese. Two online surveys on Cheddar cheese color and flavor attributes (n = 1,226 and n = 1,183, respectively) were conducted, followed by a consumer acceptance test on 6 commercially available Cheddar cheeses (n = 196). Overall, consumers preferred light orange color in Cheddar cheese over dark orange or white Cheddar cheese, but segmentation was observed for Cheddar color preference. Light orange Cheddar and white Cheddar were perceived as approximately equal in terms of "naturalness." White and light orange Cheddars were perceived as more natural than dark orange Cheddars conceptually and in consumer acceptance testing. White Cheddar was considered most natural by 50.3% of n = 1,283 survey participants and 43.4% of n = 196 consumer acceptance test participants, whereas light orange Cheddar was perceived as most natural by 40.6% and 45.9% of these groups, respectively. A bimodal distribution was observed in both the online survey and in consumer acceptance testing for the naturalness of Cheddar cheese color, with a subset of consumers (31.4% of n = 1,183 survey participants and 30.6% of n = 196 consumer testing participants) indicating that white Cheddar was the least natural option. Consumers associated orange color in Cheddar cheese with a sharper flavor both in an online survey format and consumer acceptance testing.

Investigation of the interaction between lactones and ketones in a Cheddar cheese matrix using Feller's additive model, σ-τ plots, U-models, and aroma addition experiments.

The objective of this study was to examine the sensory interactions between lactones and ketones in a Cheddar simulation matrix through perceptual interaction analysis. The olfactory thresholds of 6 key lactones had values ranging from 8.32 to 58.88 µg/kg, whereas those of the 4 key ketones ranged from 6.61 to 660.69 µg/kg. Both Feller's additive model and σ-τ plots demonstrated complex interactions in 24 binary mixtures composed of the 6 lactones and 4 ketones, including synergy, addition, and masking effects. Specifically, we found that 6 binary mixtures exhibited aroma synergistic effects using both methods. Moreover, the σ-τ plot showed a synergistic effect of aroma in 3 ternary mixtures. The U-model further confirmed the synergistic effects of the 6 groups of binary systems and 3 groups of ternary systems on aroma at actual cheese concentrations. In an aroma addition experiment, the combination of δ-octalactone and diacetyl in binary mixtures had the most pronounced effect on enhancing milk flavor. In ternary mixtures, 2 combinations, namely δ-octalactone/δ-dodecalactone/diacetyl and γ-dodecalactone/δ-dodecalactone/acetoin, significantly enhanced the milky and sweet aroma properties of cheese, while also enhancing the overall acceptability of the cheese aroma.

Development and characterization of cellulose nanofiber reinforced hydroxypropyl methylcellulose films functionalized with propolis-loaded zein nanoparticles and its application for cheddar cheese storage.

Cellulose nanofiber (CNF) reinforced hydroxypropyl methylcellulose (HPMC) films were functionalized with propolis-loaded zein nanoparticles (ZNP) to develop active, printable, and heat-sealable films. The films with 0, 0.10, 0.25, 0.50, or 0.75 mg/mL propolis-loaded ZNP, named 0ZNP, 0.10ZNP, 0.25ZNP, 0.50ZNP, and 0.75ZNP, respectively, were characterized for their mechanical, physicochemical, structural, functional and optical properties and antioxidant activity. The addition of propolis-loaded ZNP did not change tensile strength (P > 0.05), but increased elongation at break (from 24.72 to 36.58 %) (P < 0.05) for 0.25ZNP film. A water contact angle increased significantly (P < 0.05) for 0.50ZNP (~45 %) and 0.75ZNP (~137 %) films. The 0.25ZNP and 0.75ZNP films were evaluated for packaging cheddar cheese under refrigerated storage for 30 days, and resulted in comparable water activity, pH, titratable acidity, and lipid oxidation (P > 0.05) with those packaged by LDPE film and vacuum package. The developed films can function as eco-friendly alternatives to single-use plastic food packaging.

Influence of acidification and re-neutralization on mineral equilibria and physicochemical properties of model cheese feed.

Cheese feed is used as spray-dryer feed in cheese powder production, where there is growing consumer demand to eliminate calcium-chelating salts (ES). To develop ES-free feed production processes, it is essential to investigate the relationship between pH, structural changes, and mineral solubilization. This study investigated the influence of acidification and pH re-neutralization on calcium equilibria and stability of ES-free model cheese feeds. The goal was to increase protein availability by solubilizing colloidal calcium phosphate (CCP) and to assess whether CCP solubilization is reversible upon re-neutralization. The extent of acidification (to pH 4.2 or pH 4.7) significantly affected the irreversibility of calcium solubilization upon re-neutralization. Moreover, re-neutralization treatment seemed to induce changes in protein-fat interactions. Feed viscosity was mainly influenced by the final pH, rather than the re-neutralization history. These results offer new insights into the complex interplay of pH, structural modifications, mineral solubilization, and stability in cheese feed production.

Properties of low-fat Cheddar cheese prepared from bovine-camel milk blends: Chemical composition, microstructure, rheology, and volatile compounds.

Making cheese from camel milk (CM) presents various challenges due to its different physicochemical properties compared with bovine milk (BM). In this study, we investigated the chemical composition, proteolysis, meltability, oiling off, texture profile, color, microstructure, and rheological properties of low-fat Cheddar cheese (LFCC) prepared from BM-CM blends. LFCC was produced from BM or BM supplemented with 15% CM (CM15) and 30% CM (CM30), and analyzed after 14, 60, 120, and 180 d of ripening at 8°C. Except for salt content, no significant differences were observed among LFCC from BM, CM15, and CM30. The addition of CM increased the meltability and oiling off in the resulting cheese throughout storage. With respect to color properties, after melting, LFCC CM30 showed lower L* values than LFCC made from BM and CM15, and a* and b* values were higher than those of BM and CM15 samples. LFCC from CM30 also exhibited lower hardness compared with the other cheeses. Moreover, LFCC made from BM showed a rough granular surface, but cheese samples made from BM-CM blends exhibited a smooth surface. The rheological parameters, including storage modulus, loss modulus, and loss tangent, varied among cheese treatments. The determined acetoin and short-chain volatile acids (C2-C6) in LFCC were affected by the use of CM, because CM15 showed significantly higher amounts than BM and CM30, respectively. The detailed interactions between BM and CM in the cheese matrix should be further investigated.

Identifying Chemical Differences in Cheddar Cheese Based on Maturity Level and Manufacturer Using Vibrational Spectroscopy and Chemometrics.

Cheese is a nutritious dairy product and a valuable commodity. Internationally, cheddar cheese is produced and consumed in large quantities, and it is the main cheese variety that is exported from Australia. Despite its importance, the analytical methods to that are used to determine cheese quality rely on traditional approaches that require time, are invasive, and which involve potentially hazardous chemicals. In contrast, spectroscopic techniques can rapidly provide molecular information and are non-destructive, fast, and chemical-free methods. Combined with partner recognition methods (chemometrics), they can identify small changes in the composition or condition of cheeses. In this work, we combined FTIR and Raman spectroscopies with principal component analysis (PCA) to investigate the effects of aging in commercial cheddar cheeses. Changes in the amide I and II bands were the main spectral characteristics responsible for classifying commercial cheddar cheeses based on the ripening time and manufacturer using FTIR, and bands from lipids, including ß'-polymorph of fat crystals, were more clearly determined through changes in the Raman spectra.

Proteolysis and therapeutic potential of bioactive peptides derived from Cheddar cheese.

Cheddar cheese-derived bioactive peptides are considered a potential component of functional foods. A positive impact of bioactive peptides on diet-related chronic, non-communicable diseases, like obesity, cardiovascular diseases, and diabetes, has been observed. Bioactive peptides possess multifunctional therapeutic potentials, including antimicrobial, immunomodulatory, antioxidant, enzyme inhibitory effects, anti-thrombotic, and phyto-pathological activities against various toxic compounds. Peptides can regulate human immune, gastrointestinal, hormonal, and neurological responses, which play an integral role in the deterrence and treatment of certain diseases like cancer, osteoporosis, hypertension, and other health disorders, as described in the present review. This review summarizes the categories of the Cheddar cheese-derived bioactive peptides, their general characteristics, physiological functions, and possible applications in healthcare.

Effect of Moderate Electric Fields on the Physical and Chemical Characteristics of Cheese Emulsions.

Cheese powder is a multifunctional ingredient that is produced by spray drying a hot cheese emulsion called cheese feed. Feed stability is achieved by manipulating calcium equilibrium using emulsifying salts. However, the increased demand for 'green' products created a need for alternative production methods. Therefore, this study investigated the impact of ohmic heating (OH) on Cheddar cheese, mineral balance, and the resulting cheese feed characteristics compared with a conventional method. A full factorial design was implemented to determine the optimal OH parameters for calcium solubilization. Electric field exposure and temperature had a positive correlation with mineral solubilization, where temperature had the greatest impact. Structural differences in pre-treated cheeses (TC) were analyzed using thermorheological and microscopic techniques. Obtained feeds were analyzed for particle size, stability, and viscosity. OH-treatment caused a weaker cheese structure, indicating the potential removal of calcium phosphate complexes. Lower component retention of OH_TC was attributed to the electroporation effect of OH treatment. Microscopic images revealed structural changes, with OH_TC displaying a more porous structure. Depending on the pre-treatment method, component recovery, viscosity, particle size distribution, and colloidal stability of the obtained feeds showed differences. Our findings show the potential of OH in mineral solubilization; however, further improvements are needed for industrial application.

Taxonomy, Sequence Variance and Functional Profiling of the Microbial Community of Long-Ripened Cheddar Cheese Using Shotgun Metagenomics.

Shotgun metagenomic sequencing was used to investigate the diversity of the microbial community of Cheddar cheese ripened over 32 months. The changes in taxa abundance were compared from assembly-based, non-assembly-based, and mOTUs2 sequencing pipelines to delineate the community profile for each age group. Metagenomic assembled genomes (MAGs) passing the quality threshold were obtained for 11 species from 58 samples. Although Lactococcus cremoris and Lacticaseibacillus paracasei were dominant across the shotgun samples, other species were identified using MG-RAST. NMDS analysis of the beta diversity of the microbial community revealed the similarity of the cheeses in older age groups (7 months to 32 months). As expected, the abundance of Lactococcus cremoris consistently decreased over ripening, while the proportion of permeable cells increased. Over the ripening period, the relative abundance of viable Lacticaseibacillus paracasei progressively increased, but at a variable rate among trials. Reads attributed to Siphoviridae and Ascomycota remained below 1% relative abundance. The functional profiles of PMA-treated cheeses differed from those of non-PMA-treated cheeses. Starter rotation was reflected in the single nucleotide variant profiles of Lactococcus cremoris (SNVs of this species using mOTUs2), while the incoming milk was the leading factor in discriminating Lacticaseibacillus paracasei/casei SNV profiles. The relative abundance estimates from Kraken2, non-assembly-based (MG-RAST) and marker gene clusters (mOTUs2) were consistent across age groups for the two dominant taxa. Metagenomics enabled sequence variant analysis below the bacterial species level and functional profiling that may affect the metabolic interactions between subpopulations in cheese during ripening, which could help explain the overall flavour development of cheese. Future work will integrate microbial variants with volatile profiles to associate the development of compounds related to cheese flavour at each ripening stage.

Understanding animal-based flavor generation, mechanisms and characterization: Cheddar cheese and bacon flavors.

Natural animal-based flavors have great appeal to consumers and have broad applications in the food industry. In this review, we summarized findings related to bacon and Cheddar cheese flavors' components and their precursors, reaction mechanisms, influential factors, and characterization methods. The results show that free sugars, free amino acids, peptides, vitamins, lipids, and nitrites are precursors to bacon flavor. The conditions governing the formation of bacon flavor are thermally dependent, which facilitates the use of thermal food processing to generate such a flavor. For Cheddar cheese flavor, milk ingredients such as lactose, citrate, fat, and casein are reported as precursors. The optimum conditions to generate Cheddar cheese flavor from precursors are quite strict, which limits its application in food processing. As an alternative, it is more practical to generate Cheddar cheese flavor by combining key aroma compounds using thermal food processing. This review provides the food industry the comprehensive information about the generation of bacon and Cheddar cheese flavors using precursor molecules.

The Peptide Fractions of Cheddar Cheese Made with Lactobacillus helveticus 1.0612 Play Protective Effects in H2O2-Induced Oxidative-Damaged Caco-2 Cells Models.

In this study, water-soluble peptide (WSP) fractions of cheddar cheese made with Lactobacillus helveticus 1.0612 were purified into WSP-Ⅰ (<3 kDa), WSP-Ⅱ (3-10 kDa), and WSP-Ⅲ (>10 kDa). The protective effects of WSP, WSP-Ⅰ, WSP-Ⅱ, and WSP-Ⅲ fractions against oxidative stress in Caco-2 cells were assayed, and the cytoprotective mechanism of WSP-Ⅰ on cells oxidative damage was elucidated via metabolomics. The results showed that all four peptide fractions were able to attenuate the decrease in cell viability caused by oxidative stress and also could reduce the production of reactive oxygen species and malondialdehyde caused by oxidative stress, and increased cellular catalase and superoxide dismutase activities, thereby enhancing cellular antioxidant capacity. The WSP-Ⅰ fraction with the highest protective effect was used for metabolomics analysis, and 15 significantly different metabolites were screened. Functional pathway analysis revealed that the protective effect of the WSP-I fraction was related with nine metabolic pathways and weakened the metabolic disorders caused by H2O2 via regulating energy metabolism and amino acid metabolism. All in all, peptide fractions of cheddar cheese showed a cytoprotective effect through improved cellular metabolism.

Analysis of the effect of Tenebrio Molitor rennet on the flavor formation of Cheddar cheese during ripening based on gas chromatography-ion mobility spectrometry (GC-IMS).

This study aimed to evaluate the potential application of Tenebrio Molitor rennet (TMR) in Cheddar cheese production, and to use gas chromatography-ion mobility spectrometry (GC-IMS) to monitor flavor compounds and fingerprints of cheese during ripening. The results indicated that Cheddar cheese prepared from TMR (TF) has fat content significantly lower than that of commercial rennet (CF) (p < 0.05). However, the results of the sensory evaluation showed that there were no statistically significant differences between the two kinds of cheese (p > 0.05). Both cheeses were rich in free amino acids and free fatty acids. Compared to the CF cheese, gamma-aminobutyric acid and Ornithine contents of the TF cheese reached 187 and 749 mg/kg, respectively, during 120 days of ripening. Moreover, GC-IMS provided information on the characteristics of 40 flavor substances (monomers and dimers) in the TF cheese during ripening. Only 30 flavor substances were identified in the CF cheese. The fingerprint of the two kinds of cheese during ripening can be established by GC-IMS and principal component analysis based on the identified flavor compounds. Therefore, TMR has potential application in Cheddar cheese production. GC-IMS might be applied for the quick, accurate and comprehensive monitoring of cheese flavor during ripening.

Improving microbial and lipid oxidative stability of cheddar cheese using cricket protein hydrolysates pre-treated with microwave and ultrasonication.

The study was carried out to investigate cricket protein hydrolysates' (CPH) potential to enhance the storage stability of cheddar cheese. The cricket protein (CP) samples pre-processed with microwave (T1), ultrasonication (T2) or without pre-treatment (T0) were used for developing the CPH using alcalase enzyme (3%). Freeze-dried CPH were incorporated in the cheese samples (CPH-T1, CPH-T2 and CPH-T0) at the maximum level of 1.5% and were analysed for quality during 3 months of storage (4 ± 1 °C) compared to the control samples without CPH. The pre-treatments significantly improved the antimicrobial and antioxidant potential of the CPH. The CPH exhibited a significant positive effect on antioxidant potential, lipid stability, protein oxidation, microbial growth, and sensory quality of the cheddar cheese during storage. Digestion simulation showed a significant positive impact on the antioxidant activity of the cheddar cheese. Our results indicate the potential of CPH to enhance the quality of fat-rich foods during storage.

Physicochemical, microbial, and functional attributes of processed Cheddar cheese fortified with olive oil-whey protein isolate emulsion.

Olive (Olea europaea L.) has triacylglycerols, phenolics, and other antioxidants in its composition playing significant roles in maintaining health and reducing the onset of diseases. This study aimed to analyze the quality, antioxidant, textural profile, and sensory properties of processed Cheddar cheese fortified with 0%, 5%, 10%, 15%, and 20% (v/w) olive oil-whey protein isolate emulsion during 60 days of storage period. The results showed that processed cheese had significantly higher (p < .05) antioxidant activity, and total phenolic and flavonoids contents, whereas nonsignificant increase (p > .05) in moisture and acidity while decreasing tendencies in pH, fat, protein, and ash contents. Sensory analysis showed that processed Cheddar cheese with 5% emulsion had higher taste, aroma, texture/appearance, overall acceptability scores, and hardness. Conclusively, results indicated that olive oil-whey protein isolate emulsion could be beneficial for manufacturing and commercializing processed cheeses, analogs, or spreads with improved nutritional value and sensory characteristics.

Evaluation of Pediococcus acidilacticiAS185 as an adjunct culture in probiotic cheddar cheese manufacture.

A novel probiotic Pediococcus acidilactici AS185, isolated from traditional Chinese fermented foods, was used as an adjunct culture for probiotic cheddar cheese production. The physicochemical composition, textural, free amino acids (FAAs), short-chain fatty acids (SCFAs) profiles, sensory properties, and microbial survival, was evaluated during the 90-day ripening period. The addition of P. acidilactici AS185 did not influence the physicochemical composition of cheddar cheese but significantly decreased the hardness without affecting its textural profile. During ripening, P. acidilactici AS185 was able to grow and promote the generation of FAAs and SCFAs, but did not alter the overall sensory properties; it rather improved the flavor and taste of cheese. In addition, the cheese matrix protected strain P. acidilactici AS185 during transit throughout the simulated gastrointestinal system. These results demonstrated that P. acidilactici AS185 adjunct cultures might be useful for producing high-quality probiotic cheddar cheese.

Characterization of the key nonvolatile metabolites in Cheddar cheese by partial least squares regression (PLSR), reconstitution, and omission.

Cheddar cheese was desirable by consumers worldwide due to its characteristic taste and aroma, but limited information was available about taste contributors. Therefore, sensory profiles of natural Cheddar cheeses were investigated by quantitative descriptive analysis (QDA). Umami, salty, and brothy attributes were the principal differential attributes. Nonvolatile metabolites were analyzed to decipher their taste contributions, of which free amino acids (FAAs) and organic acids recorded the most considerable differences. The key taste compounds were identified by partial least squares regression (PLSR), reconstitution, and omission tests. NaCl and glutamic acid (Glu) were the primary contributors of salty and umami tastes, respectively. Sourness was synergistically affected by organic acids and Glu. Despite their limited taste impacts, the remaining amino acids intensified sourness and saltiness when mixed with Glu. Organic acids (especially in combination) and NaCl exhibited significant taste enhancements. These results provided deep insight into crucial nonvolatile metabolites promoting Cheddar cheese tastes.

Slower proteolysis in Cheddar cheese made from high-protein cheese milk is due to an elevated whey protein content.

A growing number of companies within the cheese-making industry are now using high-protein (e.g., 4-5%) milks to increase cheese yield. Previous studies have suggested that cheeses made from high-protein (both casein and whey protein; WP) milks may ripen more slowly; one suggested explanation is inhibition of residual rennet activity due to elevated WP levels. We explored the use of microfiltration (MF) to concentrate milk for cheese-making, as that would allow us to concentrate the casein while varying the WP content. Our objective was to determine if reducing the level of WP in concentrated cheese milk had any impact on cheese characteristics, including ripening, texture, and nutritional profile. Three types of 5% casein standardized and pasteurized cheese milks were prepared that had various casein:true protein (CN:TP) ratios: (a) control with CN:TP 83:100, (b) 35% WP reduced, 89:100 CN:TP, and (c) 70% WP reduced, 95:100 CN:TP. Standardized milks were preacidified to pH 6.2 with dilute lactic acid during cheese-making. Composition, proteolysis, textural, rheological, and sensory properties of cheeses were monitored over a 9-mo ripening period. The lactose, total solids, total protein, and WP contents in the 5% casein concentrated milks were reduced with increasing levels of WP removal. All milks had similar casein and total calcium levels. Cheeses had similar compositions, but, as expected, lower WP levels were observed in the cheeses where WP depletion by MF was performed on the cheese milks. Cheese yield and nitrogen recoveries were highest in cheese made with the 95:100 CN:TP milk. These enhanced recoveries were due to the higher fraction of nitrogen being casein-based solids. Microfiltration depletion of WP did not affect pH, sensory attributes, or insoluble calcium content of cheese. Proteolysis (the amount of pH 4.6 soluble nitrogen) was lower in control cheeses compared with WP-reduced cheeses. During ripening, the hardness values and the temperature of the crossover point, an indicator of the melting point of the cheese, were higher in the control cheese. It was thus likely that the higher residual WP content in the control cheese inhibited proteolysis during ripening, and the lower breakdown rate resulted in its higher hardness and melting point. There were no major differences in the concentrations of key nutrients with this WP depletion method. Cheese milk concentration by MF provides the benefit of more typical ripening rates.

Identification of aroma-active compounds in Cheddar cheese imparted by wood smoke.

Cheddar cheese is the most popular cheese in the United States, and the demand for specialty categories of cheese, such as smoked cheese, are rising. The objective of this study was to characterize the flavor differences among Cheddar cheeses smoked with hickory, cherry, or apple woods, and to identify important aroma-active compounds contributing to these differences. First, the aroma-active compound profiles of hickory, cherry, and apple wood smokes were analyzed by solid-phase microextraction (SPME) gas chromatography-olfactometry (GCO) and gas chromatography-mass spectrometry (GC-MS). Subsequently, commercial Cheddar cheeses smoked with hickory, cherry, or apple woods, as well as an unsmoked control, were evaluated by a trained sensory panel and by SPME GCO and GC-MS to identify aroma-active compounds. Selected compounds were quantified with external standard curves. Seventy-eight aroma-active compounds were identified in wood smokes. Compounds included phenolics, carbonyls, and furans. The trained panel identified distinct sensory attributes and intensities among the 3 cheeses exposed to different wood smokes (P < 0.05). Hickory smoked cheeses had the highest intensities of flavors associated with characteristic "smokiness" including smoke aroma, overall smoke flavor intensity, and meaty, smoky flavor. Cherry wood smoked cheeses were distinguished by the presence of a fruity flavor. Apple wood smoked cheeses were characterized by the presence of a waxy, green flavor. Ninety-nine aroma-active compounds were identified in smoked cheeses. Phenol, guaiacol, 4-methylguaiacol, and syringol were identified as the most important compounds contributing to characteristic "smokiness." Benzyl alcohol contributed to the fruity flavor in cherry wood smoked cheeses, and 2-methyl-2-butenal and 2-ethylfuran were responsible for the waxy, green flavor identified in apple wood smoked cheeses. These smoke flavor compounds, in addition to diacetyl and acetoin, were deemed important to the flavor of cheeses in this study. Results from this study identified volatile aroma-active compounds contributing to differences in sensory perception among Cheddar cheeses smoked with different wood sources.

Microbial and chemical composition of Cheddar cheese supplemented with prebiotics from pasteurized milk to aging.

Microbial and chemical properties of cheese is crucial in the dairy industry to understand their effects on cheese quality. Microorganisms within this fat, protein, and water matrix are largely responsible for physiochemical characteristics and associated quality. Prebiotics can be used as an energy source for lactic acid bacteria in cheese by altering the microbial community and provide the potential for value-added foods, with a more stable probiotic population. This research focuses on the addition of fructooligosaccharides (FOS) or inulin to the Cheddar cheese-making process to evaluate the effects on microbial and physicochemical composition changes. Laboratory-scale Cheddar cheese produced in 2 replicates was supplemented with 0 (control), 0.5, 1.0, and 2.0% (wt/wt) of FOS or inulin using 18 L of commercially pasteurized milk. A total of 210 samples (15 samples per replicate of each treatment) were collected from cheese-making procedure and aging period. Analysis for each sample were performed for quantitative analysis of chemical and microbial composition. The prevalence of lactic acid bacteria (log cfu/g) in Cheddar cheese supplemented with FOS (6.34 ± 0.11 and 8.99 ± 0.46; ± standard deviation) or inulin (6.02 ± 0.79 and 9.08 ± 1.00) was significantly higher than the control (5.84 ± 0.27 and 8.48 ± 0.06) in whey and curd, respectively. Fructooligosaccharides supplemented cheeses showed similar chemical properties to the control cheese, whereas inulin-supplemented cheeses exhibited a significantly higher moisture content than FOS and the control groups. Streptococcus and Lactococcus were predominant in all cheeses and 2% inulin and 2% FOS-supplemented cheeses possessed significant amounts of nonstarter lactic acid bacteria found to be an unidentified group of Lactobacillaceae, which emerged after 90 d of aging. In conclusion, this study demonstrates that prebiotic supplementation of Cheddar cheese results in differing microbial and chemical characteristics.

Effect of midday pasteurizer washing on thermoduric organisms and their progression through Cheddar cheese manufacturing and ripening.

Thermoduric bacteria are known to affect the quality of Cheddar cheese, with manifested defects including slits, weak body, and blowing. Thermoduric bacteria are likely to increase in numbers during cheese-making, as in-process conditions are conducive to proliferation. The present study was conducted to track thermoduric bacterial progression during an 18- to 20-h Cheddar cheese production run and during ripening when the pasteurizer was washed at midway through the production day. This study also correlated a broad range of chemical changes to the growth of thermoduric bacteria during ripening. Three independent cheese trials were performed at 3.5- ± 0.5-mo intervals. Samples were drawn in duplicates at 4 different times of the day: at the start of the run (vat 1), prior to a midday wash of the pasteurizer (vat 20), after the midday wash of the pasteurizer (vat 21), and at the end of the run (vat 42) for raw milk, pasteurized milk, and cheese. Cheeses were also tested during ripening for 6 mo. Results showed that raw milk total bacterial counts comprised 0.24% thermoduric mesophiles (TM) and 0.12% thermoduric thermophiles (TT). The thermoduric thermophilic bacterial counts increased by log10 1.23 during the pasteurizer run of 9 to 10 h, indicating a buildup of thermoduric thermophilic bacteria during the pasteurization process itself. Midday washing reduced thermophilic counts by log10 1.36, as evident by pre- and post-midday wash counts. However, a thermophilic buildup during post-midday wash was again noticed near the end of the 20-h run. We found that TT bacteria decreased in the first 60 d of ripening, whereas TM bacteria increased during the same period. However, TT bacteria increased later during 60 to 180 d of ripening. Bacillus licheniformis was the most frequently isolated bacteria in this study and was recovered at all production stages sampled during the cheese-making and ripening. We observed a significant increase in the level of orotic and uric acids in the vat made at the end of the day. No significant difference in the overall chemical composition, proteolysis, sugar, or other organic acids was observed in cheese made at the start versus the end of the production run.