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Kathryn J. Boor - One of the best experts on this subject based on the ideXlab platform.
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A practical training program for Fluid Milk defect judging should focus on initial training of panelists.
Journal of dairy science, 2020Co-Authors: N.r. Carey, Kathryn J. Boor, David J Kent, Martin Wiedmann, S.c. Murphy, Nicole H. MartinAbstract:ABSTRACT The sensory quality of Fluid Milk is of great importance to processors and consumers. Defects in the expected odor, flavor, or body of the product can affect consumer attitudes toward the product and, ultimately, willingness to purchase the product. Although many methods of sensory evaluation have been developed, defect judging is one particular method that has been used for decades in the dairy industry for evaluating Fluid Milk. Defect judging is a technique whereby panelists are trained to recognize and rate a standard set of Fluid Milk defects that originate from various sources (e.g., microbial spoilage). This technique is primarily used in processing facilities where identification of sensory defects can alert personnel to potential quality control issues in raw material quality, processing, or good manufacturing practices. In 2014–2016, a preliminary study of defective Milk judging screening and training was conducted by the Milk Quality Improvement Program at Cornell University (Ithaca, NY). The study, which included 37 staff and students from the Cornell community, used prescreenings for common odors and basic tastes, followed by uniform training to select, initially train, and retrain defect judges of unflavored high temperature, short time Fluid Milk. Significant improvements were seen in correct identification of defect attributes following initial training for all defect attributes, with the exception of fruity/fermented. However, following retraining, significant improvements were observed in only 2 defect attributes: cooked and Milk carton. These results demonstrate that initial training is important for panelists to correctly identify Fluid Milk defect attributes, but that subsequent retraining should be tailored toward specific attributes. This study provides a resource for dairy industry stakeholders to use to develop relevant and efficient training methods for Fluid Milk defect judging panels.
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Short communication: Pseudomonas azotoformans causes gray discoloration in HTST Fluid Milk
Journal of dairy science, 2017Co-Authors: Rachel L. Evanowski, Kathryn J. Boor, David J Kent, Nicole H. Martin, Samuel J. Reichler, Martin WiedmannAbstract:Pseudomonas species are well recognized as dairy product spoilage organisms, particularly due to their ability to grow at refrigeration temperatures. Although Pseudomonas-related spoilage usually manifests itself in flavor, odor, and texture defects, which are typically due to production of bacterial enzymes, Pseudomonas is also reported to cause color defects. Because of consumer complaints, a commercial dairy company shipped 4 samples of high temperature, short time (HTST)-pasteurized Milk with distinctly gray colors to our laboratory. Bacterial isolates from all 4 samples were identified as Pseudomonas azotoformans. All isolates shared the same partial 16S rDNA sequence and showed black pigmentation on Dichloran Rose Bengal Chloramphenicol agar. Inoculation of one pigment-producing P. azotoformans isolate into HTST-pasteurized Fluid Milk led to development of gray Milk after 14 d of storage at 6°C, but only in containers that had half of the total volume filled with Milk (∼500 mL of Milk in ∼1,000-mL bottles). We conclusively demonstrate that Pseudomonas can cause a color defect in Fluid Milk that manifests in gray discoloration, adding to the palette of color defects known to be caused by Pseudomonas. This information is of considerable interest to the dairy industry, because dairy processors and others may not typically associate black or gray colors in Fluid Milk with the presence of microbial contaminants but rather with product tampering (e.g., addition of ink) or other inadvertent chemical contamination.
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Identification and characterization of psychrotolerant coliform bacteria isolated from pasteurized Fluid Milk
Journal of Dairy Science, 2016Co-Authors: S.n. Masiello, A. Trmčić, N H Martin, Martin Wiedmann, Kathryn J. BoorAbstract:The presence of coliform bacteria in pasteurized Fluid Milk typically indicates that product contamination occurred downstream of the pasteurizer, but it may also indicate pasteurization failure. Although coliform detection is frequently used as a hygiene indicator for dairy products, our understanding of the taxonomic and phenotypic coliform diversity associated with dairy products is surprisingly limited. Therefore, using Pet-rifilm Coliform Count plates (3M, St. Paul, MN), we isolated coliforms from high-temperature, short-time (HTST)-pasteurized Fluid Milk samples from 21 Fluid Milk processing plants in the northeast United States. Based on source information and initial characterization using partial 16S rDNA sequencing, 240 nonredundant isolates were obtained. The majority of these isolates were identified as belonging to the genera Enterobacter (42% of isolates), Hafnia (13%), Citrobacter (12%), Serratia (10%), and Raoultella (9%); additional isolates were classified into the genera Buttiauxella, Cedecea, Kluyvera, Leclercia, Pantoea, and Rahnella. A subset of 104 representative isolates was subsequently character-ized phenotypically. Cold growth analysis in skim Milk broth showed that all isolates displayed at least a 2-log increase over 10 d at 6°C; the majority of isolates (n = 74) displayed more than a 5-log increase. In total, 43% of the representative isolates displayed lipolysis when incubated on spirit blue agar at 6°C for 14 d, whereas 71% of isolates displayed proteolysis when incubated on skim Milk agar at 6°C for 14 d. Our data indicate that a considerable diversity of coliforms is found in HTST-pasteurized Fluid Milk and that a considerable propor-tion of these coliforms have phenotypic characteristics that will allow them to cause Fluid Milk spoilage.
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A decade of improvement: New York State Fluid Milk quality.
Journal of dairy science, 2012Co-Authors: Nicole H. Martin, Martin Wiedmann, N.r. Carey, S.c. Murphy, Kathryn J. BoorAbstract:The microbiological and sensory qualities of New York State (NYS) Fluid Milk products were assessed as part of an ongoing Fluid Milk quality program. Commercially packaged pasteurized Fluid Milk samples were collected twice a year over the 10-yr period from 2001 to 2010 from 14 NYS dairy processing facilities and analyzed at the Milk Quality Improvement Program (MQIP) laboratory. Each sample was tested throughout refrigerated storage (6°C) on day initial, 7, 10, and 14 for standard plate count (SPC), coliform count (CC), and sensory quality. Over the 10-yr period, the percentage of samples with bacterial numbers below the Pasteurized Milk Ordinance (PMO) limit of 20,000 cfu/mL at d 14 postprocessing ranged from a low of 21.1% in 2002 to a high of 48.6% in 2010. Percent samples positive for coliforms during that same period ranged from a high of 26.6% in 2002 to a low of 7.5% in 2007. Mean d 14 sensory scores ranged from a low of 6.0 in 2002 to a high of 7.3 in 2007. Samples contaminated with coliforms after pasteurization have significantly higher SPC counts and significantly lower sensory scores on d 14 of shelf-life than those not contaminated with coliforms. Product factors such as fat level were not significantly associated with SPC, CC, or sensory quality of the product, whereas the factor processing plant significantly affected overall product quality. This study demonstrates that overall Fluid Milk quality in NYS, as determined by microbiological and sensory analyses, has improved over the last decade, and identifies some challenges that remain.
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tracking spore forming bacterial contaminants in Fluid Milk processing systems
Journal of Dairy Science, 2007Co-Authors: J R Huck, S.c. Murphy, B H Hammond, N H Woodcock, Kathryn J. BoorAbstract:The presence of psychrotolerant Bacillus species and related spore formers (e.g., Paenibacillus spp.) in Milk has emerged as a key biological obstacle in extending the shelf life of high-temperature, short-time pasteurized Fluid Milk beyond 14 d. A recently developed rpoB DNA sequence-based subtyping method was applied to characterize spoilage bacteria present in raw Milk supplies for 2 processing plants, and to assess transmission of these organisms into pasteurized products. Thirty-nine raw Milk samples and 11 pasteurized product samples were collected to represent the processing continuum from incoming truck loads of raw Milk to packaged products. Milk samples were held at 6°C for up to 16 d and plated for bacterial enumeration at various times throughout storage. Among the 88 bacterial isolates characterized, a total of 31 rpoB allelic types representing Bacillus and Paenibacillus spp. were identified, including 5 allelic types found in both raw Milk and finished product samples. The presence of the same bacterial subtypes in raw and commercially pasteurized Milk samples suggests that the raw Milk supply represents an important source of these spoilage bacteria. Extension of the shelf life of high-temperature, short-time pasteurized Fluid Milk products will require elimination of these organisms from Milk-processing systems.
Martin Wiedmann - One of the best experts on this subject based on the ideXlab platform.
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A practical training program for Fluid Milk defect judging should focus on initial training of panelists.
Journal of dairy science, 2020Co-Authors: N.r. Carey, Kathryn J. Boor, David J Kent, Martin Wiedmann, S.c. Murphy, Nicole H. MartinAbstract:ABSTRACT The sensory quality of Fluid Milk is of great importance to processors and consumers. Defects in the expected odor, flavor, or body of the product can affect consumer attitudes toward the product and, ultimately, willingness to purchase the product. Although many methods of sensory evaluation have been developed, defect judging is one particular method that has been used for decades in the dairy industry for evaluating Fluid Milk. Defect judging is a technique whereby panelists are trained to recognize and rate a standard set of Fluid Milk defects that originate from various sources (e.g., microbial spoilage). This technique is primarily used in processing facilities where identification of sensory defects can alert personnel to potential quality control issues in raw material quality, processing, or good manufacturing practices. In 2014–2016, a preliminary study of defective Milk judging screening and training was conducted by the Milk Quality Improvement Program at Cornell University (Ithaca, NY). The study, which included 37 staff and students from the Cornell community, used prescreenings for common odors and basic tastes, followed by uniform training to select, initially train, and retrain defect judges of unflavored high temperature, short time Fluid Milk. Significant improvements were seen in correct identification of defect attributes following initial training for all defect attributes, with the exception of fruity/fermented. However, following retraining, significant improvements were observed in only 2 defect attributes: cooked and Milk carton. These results demonstrate that initial training is important for panelists to correctly identify Fluid Milk defect attributes, but that subsequent retraining should be tailored toward specific attributes. This study provides a resource for dairy industry stakeholders to use to develop relevant and efficient training methods for Fluid Milk defect judging panels.
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rapid detection and characterization of postpasteurization contaminants in pasteurized Fluid Milk
Journal of Dairy Science, 2018Co-Authors: Alexander A Alles, Martin Wiedmann, N H MartinAbstract:Microbial spoilage of pasteurized Fluid Milk is typically due to either (1) postpasteurization contamination (PPC) with psychrotolerant gram-negative bacteria (predominantly Pseudomonas) or (2) growth of psychrotolerant sporeformers (e.g., Paenibacillus) that have the ability to survive pasteurization when present as spores in raw Milk, and to subsequently grow at refrigeration temperatures. While Fluid Milk quality has improved over the last several decades, continued reduction of PPC is hampered by the lack of rapid, sensitive, and specific methods that allow for detection of PPC in Fluid Milk, with Fluid Milk processors still often using time-consuming methods (e.g., Moseley keeping quality test). The goal of this project was to utilize a set of commercial Fluid Milk samples that are characterized by a mixture of samples with PPC due to psychrotolerant gram-negative bacteria and samples with presence and growth of psychrotolerant sporeforming bacteria to evaluate different approaches for rapid detection of PPC. Comprehensive microbiological shelf-life characterization of 105 pasteurized Fluid Milk samples obtained from 20 dairy processing plants showed that 60/105 samples reached bacterial counts >20,000 cfu/mL over the shelf-life due to PPC with gram-negative bacteria. Among these 60 samples with evidence of gram-negative PPC spoilage over the shelf-life, 100% (60/60) showed evidence of contamination with noncoliform, non-Enterobacteriaceae (EB) gram-negative bacteria (e.g., Pseudomonas), 20% (12/60) showed evidence of contamination with coliforms, and 7% (4/60) showed evidence of contamination with noncoliform EB. Among the remaining 45 samples, 28 showed levels of gram-positive bacteria above 20,000 cfu/mL and the remaining 17 samples did not exceed 20,000 cfu/mL over the shelf-life. Evaluation of the same set of 105 samples using 6 different approaches {all possible combinations of 2 different enrichment protocols (13°C or 21°C for 18 h) and 3 different plating media [crystal violet tetrazolium agar, EB Petrifilm (3M, St. Paul, MN), and Coliform Petrifilm]} showed that enrichment at 21°C for 18 h, followed by plating on crystal violet tetrazolium agar provided for the most sensitive, accelerated detection of samples that reached >20,000 cfu/mL due to PPC with psychrotolerant gram-negatives (70% sensitivity). These results show that tests still required and traditionally used in the dairy industry (e.g., coliform testing) are not suitable for monitoring for PPC. Rather, approaches that allow for detection of all gram-negative bacteria are essential for improved detection of PPC in Fluid Milk.
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Short communication: Pseudomonas azotoformans causes gray discoloration in HTST Fluid Milk
Journal of dairy science, 2017Co-Authors: Rachel L. Evanowski, Kathryn J. Boor, David J Kent, Nicole H. Martin, Samuel J. Reichler, Martin WiedmannAbstract:Pseudomonas species are well recognized as dairy product spoilage organisms, particularly due to their ability to grow at refrigeration temperatures. Although Pseudomonas-related spoilage usually manifests itself in flavor, odor, and texture defects, which are typically due to production of bacterial enzymes, Pseudomonas is also reported to cause color defects. Because of consumer complaints, a commercial dairy company shipped 4 samples of high temperature, short time (HTST)-pasteurized Milk with distinctly gray colors to our laboratory. Bacterial isolates from all 4 samples were identified as Pseudomonas azotoformans. All isolates shared the same partial 16S rDNA sequence and showed black pigmentation on Dichloran Rose Bengal Chloramphenicol agar. Inoculation of one pigment-producing P. azotoformans isolate into HTST-pasteurized Fluid Milk led to development of gray Milk after 14 d of storage at 6°C, but only in containers that had half of the total volume filled with Milk (∼500 mL of Milk in ∼1,000-mL bottles). We conclusively demonstrate that Pseudomonas can cause a color defect in Fluid Milk that manifests in gray discoloration, adding to the palette of color defects known to be caused by Pseudomonas. This information is of considerable interest to the dairy industry, because dairy processors and others may not typically associate black or gray colors in Fluid Milk with the presence of microbial contaminants but rather with product tampering (e.g., addition of ink) or other inadvertent chemical contamination.
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exposure of Fluid Milk to led light negatively affects consumer perception and alters underlying sensory properties
Journal of Dairy Science, 2016Co-Authors: N H Martin, Nancy Carey, Steven Murphy, David J Kent, Jae Bang, Tim Stubbs, Martin Wiedmann, Robin DandoAbstract:Fluid Milk consumption per capita in the United States has been steadily declining since the 1940s. Many factors have contributed to this decline, including the increasing consumption of carbonated beverages and bottled water. To meet the challenge of stemming the decline in consumption of Fluid Milk, the dairy industry must take a systematic approach to identifying and correcting for factors that negatively affect consumers’ perception of Fluid Milk quality. To that end, samples of Fluid Milk were evaluated to identify factors, with a particular focus on light-emitting diode (LED) light exposure, which negatively affect the perceived sensory quality of Milk, and to quantify their relative effect on the consumer’s experience. Fluid Milk samples were sourced from 3 processing facilities with varying microbial postprocessing contamination patterns based on historical testing. The effect of fat content, light exposure, age, and microbiological content were assayed across 23 samples of Fluid Milk, via consumer, descriptive sensory, and instrumental analyses. Most notably, light exposure resulted in a broad negative reaction from consumers, more so than samples with microbiological contamination exceeding 20,000 cfu/mL on days approaching code. The predominant implication of the study is that a component of paramount importance in ensuring the success of the dairy industry would be to protect Fluid Milk from all sources of light exposure, from processing plant to consumer.
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Identification and characterization of psychrotolerant coliform bacteria isolated from pasteurized Fluid Milk
Journal of Dairy Science, 2016Co-Authors: S.n. Masiello, A. Trmčić, N H Martin, Martin Wiedmann, Kathryn J. BoorAbstract:The presence of coliform bacteria in pasteurized Fluid Milk typically indicates that product contamination occurred downstream of the pasteurizer, but it may also indicate pasteurization failure. Although coliform detection is frequently used as a hygiene indicator for dairy products, our understanding of the taxonomic and phenotypic coliform diversity associated with dairy products is surprisingly limited. Therefore, using Pet-rifilm Coliform Count plates (3M, St. Paul, MN), we isolated coliforms from high-temperature, short-time (HTST)-pasteurized Fluid Milk samples from 21 Fluid Milk processing plants in the northeast United States. Based on source information and initial characterization using partial 16S rDNA sequencing, 240 nonredundant isolates were obtained. The majority of these isolates were identified as belonging to the genera Enterobacter (42% of isolates), Hafnia (13%), Citrobacter (12%), Serratia (10%), and Raoultella (9%); additional isolates were classified into the genera Buttiauxella, Cedecea, Kluyvera, Leclercia, Pantoea, and Rahnella. A subset of 104 representative isolates was subsequently character-ized phenotypically. Cold growth analysis in skim Milk broth showed that all isolates displayed at least a 2-log increase over 10 d at 6°C; the majority of isolates (n = 74) displayed more than a 5-log increase. In total, 43% of the representative isolates displayed lipolysis when incubated on spirit blue agar at 6°C for 14 d, whereas 71% of isolates displayed proteolysis when incubated on skim Milk agar at 6°C for 14 d. Our data indicate that a considerable diversity of coliforms is found in HTST-pasteurized Fluid Milk and that a considerable propor-tion of these coliforms have phenotypic characteristics that will allow them to cause Fluid Milk spoilage.
Maryanne Drake - One of the best experts on this subject based on the ideXlab platform.
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Validation of Fluid Milk consumer segments using qualitative multivariate analysis.
Journal of dairy science, 2020Co-Authors: W.s. Harwood, Maryanne DrakeAbstract:ABSTRACT Consumption of Fluid Milk in the United States has declined in recent years. To increase appeal and meet ever-changing consumer demands, several product features have been introduced to the Fluid Milk market. As such, it is imperative to assess consumer sentiments from both quantitative and qualitative perspectives to better understand the effect of various product offerings. The objectives of this study were to identify Fluid Milk consumer segments that were characterized by preference for specific product features and to verify those sentiments using qualitative multivariate analysis (QMA). An adaptive choice-based conjoint survey (n = 719) was designed to explore consumer desires regarding the fat content, package type, shelf life, label claims, and prices of commercial Milks. Part-worth utilities from the conjoint task were subsequently clustered, revealing 4 unique consumer segments. Representative consumers from each cluster (n = 18 total) were selected to participate in a 4-wk QMA study, consisting of a home-usage test followed by focus groups and projective mapping. Nine commercial Milks representing various pasteurization methods, label claims, and packaging types were used within the study. When analyzed by segment, significant differences in conjoint utilities for specific product features were identified. Overall, price was the largest differentiator of segments, followed by fat content, shelf life, and Milk designation. Several of the segmental differences were confirmed in the QMA study, with sentiments regarding price and Milk type (i.e., conventional, organic, local) consistent between conjoint survey and QMA for each consumer group. Within the projective mapping exercise, intrinsic sensory properties, price, and quality perception were the primary differentiators for Fluid Milks. Comments from QMA journal entries and focus groups revealed that consumer segments with preferences for nonconventional Milk types were primarily motivated by the belief that organic, local, or pasture-raised Milks were superior in sensory quality and congruent with personal values. Overall, QMA was an effective means for verifying conjoint-derived consumer groups and provided a contextual support for conjoint insights. Joint conclusions drawn from the components of this study may serve to guide marketing campaigns and new product development for Fluid Milk processors.
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Identification and characterization of Fluid Milk consumer groups
Journal of dairy science, 2018Co-Authors: W.s. Harwood, Maryanne DrakeAbstract:ABSTRACT Consumption of Fluid Milk has steadily declined over the last few decades. Understanding the attributes of Fluid Milk products that are attractive to specific consumer groups may provide a sound basis for education and marketing to encourage increased dairy consumption and reverse the downward trend. The objective of this study was to identify the attributes of Fluid Milk that specific consumer groups find attractive and attributes that suggest a higher purchase likelihood. An adaptive choice-based conjoint (ACBC) survey was designed to assess attributes of Fluid Milk. The ACBC survey included Kano, importance, labeling identification, and beliefs questions to determine the key attributes that dictated consumer purchase and consumption. Self-reported purchase habits and attitudes for organic food products were also collected. Attributes in the ACBC exercise included fat content, package type, shelf life, and label claims. Maximum difference scaling was used to rank the importance of attributes in Fluid Milk that affected purchase. Maximum difference scaling was also used to rank qualities and issues associated with organic Milk that were most motivating for those who identified as organic Milk consumers. Results were analyzed by univariate and multivariate statistics. A total of 1,163 Fluid Milk consumers completed the survey, and of those, 434 were regular purchasers of organic Milk. The ideal Fluid Milk from conjoint analysis was 2% Milkfat, organic, packaged in a plastic jug, conventionally pasteurized, and contained no additives or label claims. The belief that “organic Milk is healthier” was the most important motivator for purchases of organic Milk, followed by the beliefs that “organic Milk production encourages ethical treatment of animals” and “organic Milk production supports local farms and farmers.” Conjoint importance scores of all Fluid Milk consumers showed that Milkfat content was the most important attribute, followed by flavor, package size, and price. For all Milk consumers, designation as organic was ranked as the 8th most important of 14 attributes. Evaluation of these results on both aggregate and individual levels suggest that Fluid Milk consumers are not a homogeneous consumer group and that underlying consumer groups are led to purchase decisions by specific product features or expectations.
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Vitamin Fortification of Fluid Milk.
Journal of food science, 2017Co-Authors: Eileen B. Yeh, David M. Barbano, Maryanne DrakeAbstract:Vitamin concentrates with vitamins A and D are used for fortification of Fluid Milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified Milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of Fluid Milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in Fluid Milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of Fluid Milk.
David M. Barbano - One of the best experts on this subject based on the ideXlab platform.
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the effect of vitamin concentrates on the flavor of pasteurized Fluid Milk
Journal of Dairy Science, 2017Co-Authors: E B Yeh, David M. Barbano, A N Schiano, M A DrakeAbstract:ABSTRACT Fluid Milk consumption in the United States continues to decline. As a result, the level of dietary vitamin D provided by Fluid Milk in the United States diet has also declined. Undesirable flavor(s)/off flavor(s) in Fluid Milk can negatively affect Milk consumption and consumer product acceptability. The objectives of this study were to identify aroma-active compounds in vitamin concentrates used to fortify Fluid Milk, and to determine the influence of vitamin A and D fortification on the flavor of Milk. The aroma profiles of 14 commercial vitamin concentrates (vitamins A and D), in both oil-soluble and water-dispersible forms, were evaluated by sensory and instrumental volatile compound analyses. Orthonasal thresholds were determined for 8 key aroma-active compounds in skim and whole Milk. Six representative vitamin concentrates were selected to fortify skim and 2% fat pasteurized Milks (vitamin A at 1,500–3,000 IU/qt, vitamin D at 200–1,200 IU/qt, vitamin A and D at 1,000/200–6,000/1,200 IU/qt). Pasteurized Milks were evaluated by sensory and instrumental volatile compound analyses and by consumers. Fat content, vitamin content, and fat globule particle size were also determined. The entire experiment was done in duplicate. Water-dispersible vitamin concentrates had overall higher aroma intensities and more detected aroma-active compounds than oil-soluble vitamin concentrates. Trained panelists and consumers were able to detect flavor differences between skim Milks fortified with water-dispersible vitamin A or vitamin A and D, and unfortified skim Milks. Consumers were unable to detect flavor differences in oil-soluble fortified Milks, but trained panelists documented a faint carrot flavor in oil-soluble fortified skim Milks at higher vitamin A concentrations (3,000–6,000 IU). No differences were detected in skim Milks fortified with vitamin D, and no differences were detected in any 2% Milk. These results demonstrate that vitamin concentrates may contribute to off flavor(s) in Fluid Milk, especially in skim Milk fortified with water-dispersible vitamin concentrates.
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Vitamin Fortification of Fluid Milk.
Journal of food science, 2017Co-Authors: Eileen B. Yeh, David M. Barbano, Maryanne DrakeAbstract:Vitamin concentrates with vitamins A and D are used for fortification of Fluid Milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified Milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of Fluid Milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in Fluid Milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of Fluid Milk.
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Influence of raw Milk quality on Fluid Milk shelf life.
Journal of dairy science, 2006Co-Authors: David M. Barbano, Y Ma, M V SantosAbstract:Pasteurized Fluid Milk shelf life is influenced by raw Milk quality. The microbial count and somatic cell count (SCC) determine the load of heat-resistant enzymes in Milk. Generally, high levels of psychrotrophic bacteria in raw Milk are required to contribute sufficient quantities of heat-stable proteases and lipases to cause breakdown of protein and fat after pasteurization. Sanitation, refrigeration, and the addition of CO2 to Milk are used to control both total and psychrotrophic bacteria count. It is not uncommon for total bacterial counts of raw Milk to be < 10,000 cfu/mL. In the past, Fluid Milk processors have not focused much attention on Milk SCC. Increased SCC is correlated with increased amounts of heat-stable protease (plasmin) and lipase (lipoprotein lipase) in Milk. When starting with raw Milk that has a low bacterial count, and in the absence of microbial growth in pasteurized Milk, enzymes associated with high SCC will cause protein and fat degradation during refrigerated storage, and produce off-flavors. As the ability to kill, remove, or control microbial growth in pasteurized refrigerated Milk continues to improve, the original Milk SCC will be the factor limiting the time of refrigerated storage before development of an off-flavor in Milk. Most healthy cows in a dairy herd have a Milk SCC < 50,000 cell/mL. Bulk tank SCC > 200,000 cell/mL are usually due to the contribution of high SCC Milk from a small number of cows in the herd. Technology to identify these cows and keep their Milk out of the bulk tank could substantially increase the value of the remaining Milk for use in Fluid Milk processing. To achieve a 60- to 90-d shelf life of refrigerated Fluid Milk, Fluid processors and dairy farmers need to work together to structure economic incentives that allow farmers to produce Milk with the SCC needed for extended refrigerated shelf life.
M V Santos - One of the best experts on this subject based on the ideXlab platform.
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influence of raw Milk quality on Fluid Milk shelf life
Journal of Dairy Science, 2006Co-Authors: D M Arbano, M V SantosAbstract:Pasteurized Fluid Milk shelf life is influenced by raw Milk quality. The microbial count and somatic cell count (SCC) determine the load of heat-resistant enzymes in Milk. Generally, high levels of psychrotrophic bacteria in raw Milk are required to contribute sufficient quantities of heat-stable proteases and lipases to cause breakdown of protein and fat after pasteurization. Sanitation, refrigeration, and the addition of CO2 to Milk are used to control both total and psychrotrophic bacteria count. It is not uncommon for total bacterial counts of raw Milk to be 200,000 cell/mL are usually due to the contribution of high SCC Milk from a small number of cows in the herd. Technology to identify these cows and keep their Milk out of the bulk tank could substantially increase the value of the remaining Milk for use in Fluid Milk processing. To achieve a 60- to 90-d shelf life of refrigerated Fluid Milk, Fluid processors and dairy farmers need to work together to structure economic incentives that allow farmers to produce Milk with the SCC needed for extended refrigerated shelf life.
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Influence of raw Milk quality on Fluid Milk shelf life.
Journal of dairy science, 2006Co-Authors: David M. Barbano, Y Ma, M V SantosAbstract:Pasteurized Fluid Milk shelf life is influenced by raw Milk quality. The microbial count and somatic cell count (SCC) determine the load of heat-resistant enzymes in Milk. Generally, high levels of psychrotrophic bacteria in raw Milk are required to contribute sufficient quantities of heat-stable proteases and lipases to cause breakdown of protein and fat after pasteurization. Sanitation, refrigeration, and the addition of CO2 to Milk are used to control both total and psychrotrophic bacteria count. It is not uncommon for total bacterial counts of raw Milk to be < 10,000 cfu/mL. In the past, Fluid Milk processors have not focused much attention on Milk SCC. Increased SCC is correlated with increased amounts of heat-stable protease (plasmin) and lipase (lipoprotein lipase) in Milk. When starting with raw Milk that has a low bacterial count, and in the absence of microbial growth in pasteurized Milk, enzymes associated with high SCC will cause protein and fat degradation during refrigerated storage, and produce off-flavors. As the ability to kill, remove, or control microbial growth in pasteurized refrigerated Milk continues to improve, the original Milk SCC will be the factor limiting the time of refrigerated storage before development of an off-flavor in Milk. Most healthy cows in a dairy herd have a Milk SCC < 50,000 cell/mL. Bulk tank SCC > 200,000 cell/mL are usually due to the contribution of high SCC Milk from a small number of cows in the herd. Technology to identify these cows and keep their Milk out of the bulk tank could substantially increase the value of the remaining Milk for use in Fluid Milk processing. To achieve a 60- to 90-d shelf life of refrigerated Fluid Milk, Fluid processors and dairy farmers need to work together to structure economic incentives that allow farmers to produce Milk with the SCC needed for extended refrigerated shelf life.