Fluid milk vitamin fortification compliance in New York State

Current US regulations, as specified in the Pasteurized Milk Ordinance, require vitamin A fortification of all reduced fat fluid milk products. The addition of vitamin D is optional in all fluid products. Acceptable vitamin concentrations in fortified milks are 2000 to 3000 International units per quart for vitamin A and 400 to 600 International units per quart for vitamin D. Vitamin A and D levels were analyzed in fortified milk products collected over a 4-yr period in New York State. Samples of whole fat, 2% fat, 1% fat, and nonfat milks were collected twice per year from up to 31 dairy processing plants. For vitamin A, 44.5% of 516 samples were in compliance with current regulations, and 47.7% of 648 samples were within the acceptable range for vitamin D. Most milk samples that were out of compliance were underfortified.     

The effect of vitamin concentrates on the flavor of pasteurized fluid milk

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.     

High temperature, short time pasteurization temperatures inversely affect bacterial numbers during refrigerated storage of pasteurized fluid milk

The grade A Pasteurized Milk Ordinance specifies minimum processing conditions of 72°C for at least 15 s for high temperature, short time (HTST) pasteurized milk products. Currently, many US milk-processing plants exceed these minimum requirements for fluid milk products. To test the effect of pasteurization temperatures on bacterial numbers in HTST pasteurized milk, 2% fat raw milk was heated to 60°C, homogenized, and treated for 25 s at 1 of 4 different temperatures (72.9, 77.2, 79.9, or 85.2°C) and then held at 6°C for 21 d. Aerobic plate counts were monitored in pasteurized milk samples at d 1, 7, 14, and 21 postprocessing. Bacterial numbers in milk processed at 72.9°C were lower than in milk processed at 85.2°C on each sampling day, indicating that HTST fluid milk-processing temperatures significantly affected bacterial numbers in fluid milk. To assess the microbial ecology of the different milk samples during refrigerated storage, a total of 490 psychrotolerant endospore-forming bacteria were identified using DNA sequence-based subtyping methods. Regardless of processing temperature, >85% of the isolates characterized at d 0, 1, and 7 postprocessing were of the genus Bacillus, whereas more than 92% of isolates characterized at d 14 and 21 postprocessing were of the genus Paenibacillus, indicating that the predominant genera present in HTST-processed milk shifted from Bacillus spp. to Paenibacillus spp. during refrigerated storage. In summary, 1) HTST processing temperatures affected bacterial numbers in refrigerated milk, with higher bacterial numbers in milk processed at higher temperatures; 2) no significant association was observed between genus isolated and pasteurization temperature, suggesting that the genera were not differentially affected by the different processing temperatures; and 3) although typically present at low numbers in raw milk, Paenibacillus spp. are capable of growing to numbers that can exceed Pasteurized Milk Ordinance limits in pasteurized, refrigerated milk.     

Effect of fat content on sensory and physico‐chemical properties of laboratory‐pasteurised calcium‐ and vitamin D‐fortified mixture of cow and buffalo milk

The influence of milk fat on physico‐chemical properties of calcium and vitamin D‐fortified milk was investigated. Sensory scores, curd tension, viscosity, rennet coagulation time and TBA value increased with the increase in fat content. Calcium and vitamin D fortification had no effect on sensory scores, whereas a significant increase was observed in curd tension and viscosity. The TBA value of fortified milk was significantly lower than that of the unfortified milk. The rennet coagulation time of milk increased significantly with addition of calcium phosphate, whereas calcium citrate fortification had no significant effect. All milk samples were stable to alcohol.     

Children's perceptions of fluid milk with varying levels of milkfat

Schools participating in federal meal programs are limited to serving skim or low-fat (≤1%) flavored and unflavored milk. Few studies have directly addressed child perceptions and preferences for milk containing different amounts of milkfat. The objective of this study was to determine whether children can differentiate between flavored and unflavored fluid milk containing varying levels of milkfat and whether preferences for certain levels of milkfat exist. Flavored and unflavored milks containing 4 different percentages of milkfat (≤0.5, 1, 2, and 3.25%) were high-temperature, short-time processed, filled into half-gallon light-shielded milk jugs, and stored at 4°C in the dark. Milks were evaluated by children (ages 8–13 yr) following 7 d at 4°C. Acceptance testing and tetrad difference testing were conducted on flavored and unflavored milks with and without visual cues to determine if differences were driven by visual or flavor or mouthfeel cues. Child acceptance testing (n = 138 unflavored; n = 123 flavored) was conducted to evaluate liking and perception of selected attributes. Tetrad testing (n = 127 unflavored; n = 129 flavored) was conducted to determine if children could differentiate between different fat levels even in the absence of a difference in acceptance. The experiment was replicated twice. When visual cues were present, children had higher overall liking for 1% and 2% milks than skim for unflavored milk and higher liking for chocolate milks containing at least 1% milk fat than for skim. Differences in liking were driven by appearance, viscosity, and flavor. In the absence of visual cues, no differences were observed in liking or flavor or mouthfeel attributes for unflavored milk but higher liking for at least 1% milk fat in chocolate milk compared with skim was consistent with the presence of visual cues. From tetrad testing, children could visually tell a difference between all unflavored pairs except 2% versus whole milk and could not detect consistent differences between milkfat pairs in the absence of visual cues. For chocolate milk, children could tell a difference between all milk fat pairs with visual cues and could tell a difference between skim versus 2% and skim versus whole milk without visual cues. These results demonstrate that in the absence of package-related flavors, school-age children like unflavored skim milk as well as milk with higher fat content in the absence of visual cues. In contrast, appearance as well as flavor and mouthfeel attributes play a role in children's liking as well as their ability to discriminate between chocolate milks containing different amounts of fat, with chocolate milk containing at least 1% fat preferred. The sensory quality of school lunch milk is vital to child preference, and processing efforts are needed to maximize school milk sensory quality.     

Stability of vitamins A and C in fortified yogurt

Plain and raspberry flavored low fat yogurt samples were fortified with various commercial forms of vitamins A and C under actual production conditions. Immediately after processing, yogurt samples were kept at 3 degrees C for 6 wk and were analyzed biweekly for pH, titratable acidity, and vitamins A and C. Data revealed that both vitamins decreased gradually in fortified yogurt with vitamin C decreasing at a higher rate than vitamin A. However, a fortification level of 10,000 IU of vitamin A and 300 mg of vitamin C per 227 g container of plain or flavored yogurt provided at least 100% of the US recommended daily allowance of both vitamins after 6 wk storage at 3 degrees C. This level of fortification did not significantly change pH, titratable acidity, or sensory characteristics of yogurt samples.     

Vitamin D content and variability in fluid milks from a US Department of Agriculture nationwide sampling to update values in the National Nutrient Database for Standard Reference

This study determined the vitamin D₃ content and variability of retail milk in the United States having a declared fortification level of 400 IU (10 μg) per quart (qt; 1 qt = 946.4 mL), which is 25% daily value per 8 fluid ounce (236.6 mL) serving. In 2007, vitamin D₃ fortified milk (skim, 1%, 2%, whole, and 1% fat chocolate milk) was collected from 24 statistically selected supermarkets in the United States. Additionally, 2% milk samples from an earlier 2001 USDA nationwide collection were reanalyzed. Vitamin D₃ was determined using a specifically validated method involving HPLC with UV spectroscopic detection and vitamin D₂ as an internal standard. Quality control materials were analyzed with the samples. Of the 120 milk samples procured in 2007, 49% had vitamin D₃ within 100 to 125% of 400 IU (10 μg)/qt (label value), 28% had 501 to 600 IU (12.5-15 μg)/qt, 16% had a level below the label amount, and 7% had greater than 600 IU (15 μg)/qt (>150% of label). Even though the mean vitamin D₃ content did not differ statistically between milk types, a wide range in values was found among individual samples, from nondetectable [<20 IU (0.5 μg)/qt] for one sample to almost 800 IU (20 μg)/qt, with a trend toward more samples of whole milk having greater than 150% of the labeled content. On average, vitamin D₃ in 2% milk was higher in 2007 compared with in 2001 [473 vs. 426 IU (11.8 vs. 10.6 μg)/qt].     

Shelf life of pasteurized microfiltered milk containing 2% fat

The goal of this research was to produce homogenized milk containing 2% fat with a refrigerated shelf life of 60 to 90 d using minimum high temperature, short time (HTST) pasteurization in combination with other nonthermal processes. Raw skim milk was microfiltered (MF) using a Tetra Alcross MFS-7 pilot plant (Tetra Pak International SA, Pully, Switzerland) equipped with Membralox ceramic membranes (1.4 μm and surface area of 2.31 m²; Pall Corp., East Hills, NY). The unpasteurized MF skim permeate and each of 3 different cream sources were blended together to achieve three 2% fat milks. Each milk was homogenized (first stage: 17 MPa, second stage: 3 MPa) and HTST pasteurized (73.8°C for 15 s). The pasteurized MF skim permeate and the 3 pasteurized homogenized 2% fat milks (made from different fat sources) were stored at 1.7 and 5.7°C and the standard plate count for each milk was determined weekly over 90 d. When the standard plate count was >20,000 cfu/mL, it was considered the end of shelf life for the purpose of this study. Across 4 replicates, a 4.13 log reduction in bacteria was achieved by MF, and a further 0.53 log reduction was achieved by the combination of MF with HTST pasteurization (73.8°C for 15 s), resulting in a 4.66 log reduction in bacteria for the combined process. No containers of MF skim milk that was pasteurized after MF exceeded 20,000 cfu/mL bacteria count during 90 d of storage at 5.7°C. The 3 different approaches used to reduce the initial bacteria and spore count of each cream source used to make the 2% fat milks did not produce any shelf-life advantage over using cold separated raw cream when starting with excellent quality raw whole milk (i.e., low bacteria count). The combination of MF with HTST pasteurization (73.8°C for 15 s), combined with filling and packaging that was protected from microbial contamination, achieved a refrigerated shelf life of 60 to 90 d at both 1.7 and 5.7°C for 2% fat milks.     

Vitamin D2 stability in milk during processing,packaging and storage

Stability of vitamin D2 in milk was determined in vitamin D2 fortified milk. Reverse phase high pressure liquid chromatography was used to determine the vitamin D₂ loss during processing, packaging and under light. The percentage losses during pasteurization, boiling and sterilization were demonstrated to be statistically insignificant. Milk was stored for seven days in both glass and plastic bottles under refrigerated temperature, non significant loss of vitamin D₂ was observed, whereas, when stored in polyethylene pouches significant loss was observed as vitamin D₂ decreased from 596.66 to 548.04 IU. This clearly indicated that vitamin D₂ was sorbed up by polyethylene material during storage resulting in its loss. Milk samples were stored for 32 h under three different light intensities (14,852,970 and 4455 lux). Non significant loss of vitamin D₂ was observed in glass packaging, whereas significant loss was observed in polyethylene pouches. In milk fortified with both calcium and vitamin D₂, non significant effect of calcium was observed on the loss of vitamin D₂.     

Concentration of furfuryl alcohol in fluid milk,dried dairy ingredients,and cultured dairy products

Maillard reactions occur in dairy products during heat treatment. Furfuryl alcohol (FA) may be found in dairy products as a result of Maillard reactions. The recent posting in California Proposition 65 indicates that FA may be carcinogenic, and for this reason it is crucial to accurately measure FA concentrations in dairy products. The objective of this study was to identify an extraction and quantitation method for FA from dairy products and to determine FA concentrations in milk, dairy powders, and cultured dairy products. Solvent-assisted flavor extraction, solid-phase microextraction, stir bar sorptive extraction with gas chromatography-mass spectrometry and triple quadrupole mass spectrometry were compared for recovery of FA. Internal standards for the quantitation of FA (2-methyl-3-heptanone, furfuryl-d₅ alcohol, 2,5-dimethylphenol, 5-methyl-2-furfuryl alcohol, and 5-methyl furfural) were also compared. Subsequently, fluid milk [high temperature, short time (HTST) and ultrapasteurized], whey protein isolates (3 mo–4 yr), whey protein concentrates (3 mo–4 yr), whole milk powders (1 yr), high and low heat skim milk powders (SMP; 0–8 yr), milk protein isolates (3 mo–3 yr), milk protein concentrates (3 mo–3 yr), Cheddar cheese (mild, medium, sharp, and extra sharp), mozzarella cheese (whole and part skim), cottage cheese (nonfat, low fat, and full fat), sour cream (nonfat, low fat, and full fat), traditional yogurt (nonfat, low fat, and full fat), and Greek-style yogurt (nonfat; n = 139 products total) were evaluated. Furfuryl alcohol was extracted from products by headspace solid-phase microextraction followed by gas chromatography-triple quadrupole mass spectrometry using a ZB-5ms column (30 m × 0.25 mm × 0.25 µm; Phenomenex Inc., Torrance, CA). Furfuryl-d₅ alcohol was used as an internal standard. Each food was extracted in triplicate. Ultrapasteurized milks had higher levels of FA than HTST milks (122.3 vs. 7.350 µg/kg). Furfuryl alcohol concentrations ranged from 0.634 to 26.55 µg/kg in whey protein isolates, 2.251 to 56.19 µg/kg in whey protein concentrates, 11.99 to 121.9 µg/kg in milk protein isolates, and 8.312 to 49.71 µg/kg in milk protein concentrates, and concentrations increased with powder storage. High heat SMP had higher concentrations of FA than low heat SMP (11.8 vs. 1.36 µg/kg) and concentrations increased with storage time. Concentrations of FA in Cheddar and mozzarella cheese ranged from 2.361 to 110.5 µg/kg and were higher than FA concentrations in cottage cheese or sour cream (0.049–1.017 µg/kg). These results suggest that FA is present at higher levels in dairy products that have been subjected to higher temperatures or have been stored longer. Sour cream and cottage cheese had lower levels of FA. Compared with other studies on food products with reported levels of FA, such as coffee (200–400 µg/g), dairy products have very low levels of FA.     

Major advances in concentrated and dry milk products, cheese, and milk fat-based spreads

Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have anticancer, anti-atherogenic, antidiabetic, and antiobesity effects for human health. Separating milk fat into fractions has been accomplished to provide specific fractions to improve butter spreadability, modulate chocolate meltability, and provide texture for low-fat cheeses.     

Increasing retention of vitamin D3 in vitamin D3 fortified ice cream with milk protein emulsifier

This study aimed to develop vitamin D₃ fortified ice cream by incorporating vitamin D₃ in an emulsified form using milk protein as emulsifier. Physicochemical stability of vitamin D₃ emulsions using different milk protein emulsifiers including nonfat dry milk, sodium caseinate (Na-Cas), and whey protein isolate was investigated. Emulsion using Na-Cas had the smallest oil droplet size and the lowest creaming index throughout the storage time (P < 0.05) and was selected to fortify in full-fat, reduced-fat, and low-fat ice creams at 250 IU per serving. Vitamin D₃ retention in each ice cream was determined after 0, 7, 14, 28 and 56 d of storage at −20 °C. The results indicated that the emulsified form of vitamin D₃ remarkably improved vitamin D₃ stability in all ice cream formulations.     

Ultra-high-temperature processing of chocolate flavoured milk

Chocolate milk with different carrageenans (κappa and lambda) and sugar concentrations was heat treated indirectly at 145 °C for 6 s using a bench-top UHT plant. The temperature of the milk in the preheating and sterilizer sections, and the milk flow rate were determined to evaluate the overall heat transfer coefficient (OHTC) for monitoring fouling during UHT processing. Kappa-carrageenan was more effective than lambda-carrageenan in providing stability against fouling during UHT processing. By optimizing concentrations of κ-carrageenan and sugar, fouling could be minimized during UHT processing. The apparent viscosity and sedimentation of UHT-processed chocolate milk increased with increasing concentration of carrageenan and sugar.     

Effects of milk powders in milk chocolate

The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products.     

Influence of packaging information on consumer liking of chocolate milk

Chocolate milk varies widely in flavor, color, and viscosity, and liking is influenced by these properties. Additionally, package labels (declared fat content) and brand are some of the extrinsic factors that may influence consumer perception. The objective of this study was to evaluate the effects of packaging labels and brand name on consumer liking and purchase intent of chocolate milk. A consumer acceptance test, conjoint analysis survey, and Kano analysis were conducted. One hundred eight consumers evaluated 7 chocolate milks with and without brand or package information in a 2-d crossover design. A conjoint analysis survey and Kano analysis were conducted after the consumer acceptance test. Results were evaluated by 2-way ANOVA and multivariate analyses. Declared fat content and brand influenced overall liking and purchase intent for chocolate milks to differing degrees. A subsequent conjoint analysis (n = 250) revealed that fat content was a driver of choice for purchasing chocolate milk followed by sugar content and brand. Brand name was less important for purchase intent of chocolate milk than fat or sugar content. Among fat content of chocolate milk, 2 and 1% fat level were most appealing to consumers, and reduced sugar and regular sugar were equally important for purchase intent. Kano analysis confirmed that fat content (whole milk, 1, or 2% fat chocolate milk) was an attractive attribute for consumer satisfaction, more so than brand. Organic labeling did not affect the purchase decision of chocolate milk; however, Kano results revealed that having an organic label on a package positively influenced consumer satisfaction. Findings from this study can help chocolate milk producers as well as food marketers better target their product labels with attributes that drive consumer choice of chocolate milk.     

Reduction of pasteurization temperature leads to lower bacterial outgrowth in pasteurized fluid milk during refrigerated storage: a case study

Bacterial numbers over refrigerated shelf-life were enumerated in high-temperature, short-time (HTST) commercially pasteurized fluid milk for 15 mo before and 15 mo after reducing pasteurization temperature from 79.4°C (175°F) [corrected] to 76.1°C (169°F). Total bacterial counts were measured in whole fat, 2% fat, and fat-free milk products on the day of processing as well as throughout refrigerated storage (6°C) at 7, 14, and 21 d postprocessing. Mean total bacterial counts were significantly lower immediately after processing as well as at 21 d postprocessing in samples pasteurized at 76.1°C versus samples pasteurized at 79.4°C. In addition to mean total bacterial counts, changes in bacterial numbers over time (i.e., bacterial growth) were analyzed and were lower during refrigerated storage of products pasteurized at the lower temperature. Lowering the pasteurization temperature for unflavored fluid milk processed in a commercial processing facility significantly reduced bacterial growth during refrigerated storage.     

Effects of dietary vitamin D3 on concentrations of vitamin D and its metabolites in blood plasma and milk of dairy cows

To determine the effect of supplemental dietary vitamin D3 on concentration of vitamin D and its metabolites in milk, 20 Holstein cows were assigned to four groups and fed either 0, 10,000, 50,000, or 250,000 IU of vitamin D3/d beginning approximately 2 wk prepartum and continuing through wk 12 of lactation. Samples of blood plasma and milk were assayed for concentrations of vitamin D, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D. Only the daily dosage of 250,000 IU caused significant increases of concentrations of vitamin D or 25-hydroxyvitamin D in plasma. Concentrations of vitamin D and 25-hydroxyvitamin D in milk were approximately equal and averaged .2 ng/ml. Little 1,25-dihydroxyvitamin D and no 24,25-dihydroxyvitamin D could be detected in milk from any of the four treatment groups. Cows fed 250,000 IU of vitamin D3/d produced milk containing 54 IU of vitamin D activity per liter, whereas unsupplemented cows produced milk containing 17 IU/L. Oral supplementation with up to 250,000 IU of vitamin D3/d does not increase effectively vitamin D activity of milk.     

Flavor and flavor chemistry differences among milks processed by high-temperature,short-time pasteurization or ultra-pasteurization

Typical high-temperature, short-time (HTST) pasteurization encompasses a lower heat treatment and shorter refrigerated shelf life compared with ultra-pasteurization (UP) achieved by direct steam injection (DSI-UP) or indirect heat (IND-UP). A greater understanding of the effect of different heat treatments on flavor and flavor chemistry of milk is required to characterize, understand, and identify the sources of flavors. The objective of this study was to determine the differences in the flavor and volatile compound profiles of milk subjected to HTST, DSI-UP, or IND-UP using sensory and instrumental techniques. Raw skim and raw standardized 2% fat milks (50 L each) were processed in triplicate and pasteurized at 78°C for 15 s (HTST) or 140°C for 2.3 s by DSI-UP or IND-UP. Milks were cooled and stored at 4°C, then analyzed at d 0, 3, 7, and 14. Sensory attributes were determined using a trained panel, and aroma active compounds were evaluated by solid-phase micro-extraction or stir bar sorptive extraction followed by gas chromatography-mass spectrometry, gas chromatography-olfactometry, and gas chromatography-triple quad mass spectrometry. The UP milks had distinct cooked and sulfur flavors compared with HTST milks. The HTST milks had less diversity in aroma active compounds compared with UP milks. Flavor intensity of all milks decreased by d 14 of storage. Aroma active compound profiles were affected by heat treatment and storage time in both skim and 2% milk. High-impact aroma active compounds were hydrogen sulfide, dimethyl trisulfide, and methional in DSI-UP and 2 and 3-methylbutanal, furfural, 2-heptanone, 2-acetyl-1-pyrroline, 2-aminoacetophenone, benzaldehyde, and dimethyl sulfide in IND-UP. These results provide a foundation knowledge of the effect of heat treatments on flavor development and differences in sensory quality of UP milks.