Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: The objective of the research was to determine the efficacy of a microfiltration (MF) and pasteurization process in extending the shelf life of 2% fat milk. Raw skim milk (ca. 273 kg) from the Cornell University dairy plant was MF at 50 C using a Tetra Alcross M7 Pilot Plant equipped with a ceramic Membralox membrane (pore diameter: 1.4 micron) and collected directly into a sterile containers. Approximately 95 percent of the milk was collected as permeate. The collection container was connected directly to a shell and tube pasteurization system. The 50 C permeate was pasteurized at 72 C for 15 s, and collected directly into another sterile container. The experiment was replicated 3 times. Bacteria counts of raw skim were done by standard plate count. Bacteria counts of MF and pasteurized MF milk were determined using a most probable number (MPN) method. For the MPN method, five containers each with 1, 10, 100 and 500 mL of milk were incubated at 32C for 6 days. Growth or no growth in each container was determined using a Foss BactoScanTM FC. The MPN bacteria count was calculated using a spreadsheet developed by FDA/CFSAN. At 4 C, a 60 to 90 day shelf-life (i.e., bacteria count <20,000 cfu/mL) was achieved. Shelf-life of 90 days at 43F with bacteria count of <20,000 cfu/mL was achieved for milk containing 2% fat. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Consumers, particularly young children prefer the fresh taste of HTST milk to UHT milk. The marketing and distribution system for fluid milk and milk based beverages is changing and the distribution times and distances are longer. Combinations of HTST with other technologies, such as MF, may deliver better tasting fluid milk and milk based beverages with the longer shelf needed in today's modern marketing and distribution systems.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: The objective of the research was to determine the efficacy of a microfiltration (MF) and pasteurization process in extending the shelf life of 2% fat milk. Raw skim milk (ca. 273 kg) from the Cornell University dairy plant was MF at 50 C using a Tetra Alcross M7 Pilot Plant equipped with a ceramic Membralox membrane (pore diameter: 1.4 micron) and collected directly into a sterile containers. Approximately 95 percent of the milk was collected as permeate. The collection container was connected directly to a shell and tube pasteurization system. The 50 C permeate was pasteurized at 72 C for 15 s, and collected directly into another sterile container. The experiment was replicated 3 times. Bacteria counts of raw skim were done by standard plate count. Bacteria counts of MF and pasteurized MF milk were determined using a most probable number (MPN) method. For the MPN method, five containers each with 1, 10, 100 and 500 mL of milk were incubated at 32 C for 6 days. Growth or no
growth in each container was determined using a Foss BactoScanTM FC. The MPN bacteria count was calculated using a spreadsheet developed by FDA/CFSAN. At 4C, a 60 to 90 day shelf-life (i.e., bacteria count <20,000 cfu/mL) was achieved.
PARTICIPANTS: Individuals: Mark Newbold, Zack Caplan Collaborators: Kathryn Boor - Cornell; Pall Corporation.
TARGET AUDIENCES: Dairy Food Processors. Equipment manufacturers. Data presented at the American Dairy Science Association Annual Meeting and Industry Trade Conferences.
Impacts
Consumers, particularly young children prefer the fresh taste of HTST milk to UHT milk. The marketing and distribution system for fluid milk and milk based beverages is changing and the distribution times and distances are longer. Combinations of HTST with other technologies, such as MF, may deliver better tasting fluid milk and milk based beverages with the longer shelf needed in today's modern marketing and distribution systems.
Publications
- Barbano, D. M. and K. J. Boor. 2007. Breaking the 21 to 28 Day Shelf-Life Barrier on Refrigerated HTST Pasteurized Milk. J. Dairy Sci. 90:Supplement 184-185.
- Caplan, Z. P. and D. M. Barbano. 2007. Use of HTST Pasteurization Combined with other Nonthermal Processes to Improve Fluid Milk Shelf-Life. J. Dairy Sci. 90:Supplement 144.
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Progress 01/01/06 to 12/31/06
Outputs
The objective of the research was to determine the efficacy of a microfiltration (MF) and pasteurization process in extending the shelf life of skim milk. Raw skim milk (ca. 273 kg) from the Cornell University dairy plant was MF at 50 C using a Tetra Alcross M7 Pilot Plant equipped with a ceramic Membralox membrane (pore diameter: 1.4 micron) and collected directly into a sterile container. Approximately 95 percent of the milk was collected as permeate. The collection container was connected directly to a shell and tube pasteurization system. The 50 C permeate was pasteurized at 72 C for 15 s, and collected directly into another sterile container. The experiment was replicated 3 times. Bacteria counts of raw skim were done by standard plate count. Bacteria counts of MF and pasteurized MF milk were determined using a most probable number (MPN) method. For the MPN method, five containers each with 1, 10, 100 and 500 mL of milk were incubated at 32 C for 6 days. Growth
or no growth in each container was determined using a Foss BactoScanTM FC. The MPN bacteria count was calculated using a spreadsheet developed by FDA/CFSAN. Bacteria count of the raw milk was reduced from 2400, 3600, and 1475 cfu/mL to 0.2398, 0.9178, and 0.2398 cfu/mL, respectively, by MF. Bacterial counts in the pasteurized MF skim milk for the three trials were 0.0046, 0.0078, and 0.0045 cfu/mL respectively, demonstrating an average 5.6 log reduction from the raw count due to the combination of MF and pasteurization. At 4 C, a sixty day shelf-life was achieved. Further work is being done to refine the process and to adapt the process to milk containing 2 percent fat.
Impacts
Consumers, particularly young children prefer the fresh taste of HTST milk to UHT milk. The marketing and distribution system for fluid milk and milk based beverages is changing and the distribution times and distances are longer. Combinations of HTST with other technologies, such as MF, may deliver better tasting fluid milk and milk based beverages with the longer shelf needed in today's modern marketing and distribution systems.
Publications
- Barbano*, D.M., Ma, Y. and Santos, M.V. 2005. Influence of raw milk quality on fluid milk shelf life. J. Dairy Sci. 88:Supplement 1:77.
- Barbano*, D.M., Elwell, M.W. 2005. Use of microfiltration (MF) to improve fluid milk quality. J. Dairy Sci. 88:Supplement 1:78.
- Barbano, D. M., Y. Ma, and M. V. Santos. 2006. Influence of Raw Milk Quality on Fluid Milk Shelf life. J. Dairy Sci 89: E15-19E.
- Elwell, M. W., and D. M. Barbano. 2006. Microfiltration in the processing of extended shelf life skim milk. J. Dairy Sci. 89: E20-30E.
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Progress 01/01/04 to 12/31/04
Outputs
The objective of the research was to determine the efficacy of a microfiltration and pasteurization process in extending the shelf life of skim milk. Raw skim milk (ca. 273 kg) from the Cornell University dairy plant was microfiltered at 50 degrees C using a Tetra Alcross M7 Pilot Plant equipped with a ceramic Membralox membrane (pore diameter: 1.4 micrometer) and collected directly into a sterile container. Approximately 95 percent of the milk was collected as permeate. The collection container was connected directly to a shell and tube pasteurization system. The 50 degrees C permeate was pasteurized at 72 degrees C for 15 s, and collected directly into another sterile container. The experiment was replicated 3 times. Bacteria counts of raw skim were done by standard plate count. Bacteria counts of microfiltered and pasteurized microfiltered milk were determined using a most probable number (MPN) method. For the MPN method, five containers each with 1, 10, 100 and
500 mL of milk were incubated at 32 degrees C for 6 days. Growth or no growth in each container was determined using a Foss BactoScanTM FC. The MPN bacteria count was calculated using a spreadsheet developed by FDA/CFSAN. Bacteria count of the raw milk was reduced from 2400, 3600, and 1475 cfu/mL to 0.2398, 0.9178, and 0.2398 cfu/mL, respectively, by microfiltration. Bacterial counts in the pasteurized microfiltered skim milk for the three trials were 0.0046, 0.0078, and 0.0045 cfu/mL respectively, demonstrating an average 5.6 log reduction from the raw count due to the combination of microfiltration and pasteurization. The pasteurized microfiltered skim milk was pumped directly from the sterile collection container into 1L sterile sample containers for shelf life tests. Two sample containers were incubated at each of four temperatures (0, 2, 4, and 6 degrees C) and the total bacteria count was determined weekly until the count reached 106 cfu/mL.
Impacts
Consumers, particularly young children prefer the fresh taste of HTST milk to UHT milk. The marketing and distribution system for fluid milk and milk based beverages is changing and the distribution times and distances are longer. Combinations of HTST with other technologies, such as microfiltation, may deliver better tasting fluid milk and milk based beverages with the longer shelf needed in today's modern marketing and distribution systems.
Publications
- Elwell, M. W., and D. M. Barbano. 2004. Extending shelf life of skim milk with microfiltration. J. Dairy Sci. 87:Supplement 1:417.
- Barbano, D. M. 2004. The role of milk quality in addressing future dairy food marketing opportunities in a global economy. Pages 47-51 in Proceedings of the National Mastitis Council 43rd Annual Meeting.
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Progress 01/01/03 to 12/31/03
Outputs
Our objectives were: (1) to measure the time for pasteurized homogenized 2 percent milk to achieve a level of lipolysis and proteolysis caused by native milk enzymein milks of different somatic cell count (SCC) at 0.5 and 6 C that would be sufficient to produce an off-flavor, (2) to determine if milk fat content (i.e., 1, 2 and 3.25 percent) influences the level of proteolysis or lipolysis caused by native milk enzymes at 6oC, and (3) to determine the time in days for milks containing 2 percent fat with different SCC to undergo sufficient lipolysis or proteolysis to produce an off-flavor due to the combination of the action of native milk enzymes and microbial growth at 0.5 and 6 C. Based on the previous work, an off-flavor due to proteolysis was detected by 50 percent of panelists when the decrease in casein as a percentage of true protein (CN/TP) was greater than 4.76 percent. We estimated (assuming 50 percent of consumers would detect an off-flavor when CN/TP
decreases 5 percent) that pasteurized milk containing 2 percent fat would have an off-flavor at much greater than 61 and 54 d for the low SCC milk, and at about 54 and 19 d for the high SCC, at 0.5 and 6oC, respectively. Previous research reported that 34 percent of panelists could detect an off-flavor in milk containing 2 percent fat due to lipolysis at a (free fatty acid) FFA concentration of 0.25 meq/kg of milk. Based on these results, it can be estimated in the present study that 34 percent of panelists would detect an off-flavor in a 2 percent fat pasteurized milk with low SCC at a time long after 61 and just after 61 d at 0.5 and 6oC, respectively, while for milk with high SCC an off-flavor would be detected by 34 percent of panelist at slightly longer than 61 and 35 d at 0.5 and 6oC, respectively. The combination of low SCC milk and low storage temperature when combined with processing technology to produce very low initial bacteria count in fluid milk can produce fluid milk
that will maintain flavor quality for more than 61 d. The use of carbon dioxide during pasteurization to increase kill of bacteria and inactivation of enzymes associate with somatic cells is being investigated.
Impacts
Previous research in our laboratory demonstrated that as milk SCC increases, cheese yield decreases and the frequency of flavor defects in cheese increases. This research had the direct impact of causing cheese manufacturers to pay dairy farmers premiums for low SCC milk. In New York State alone, this returns approximate 1 to 1.5 million extra dollars per year to dairy farmers. The present research will determine if there are similar negative impacts of high SCC milk on the use value of milk fluid milk products.
Publications
- Santos, M. V., Y. Ma, Z. Caplan, and D. M. Barbano. 2003. Sensory threshold of off-flavors caused by proteolysis and lipolysis in milk. J. Dairy Sci. 86:1601-1607.
- Santos, M. V., Y. Ma, and D. M. Barbano. 2003. Effect of somatic cell count on proteolysis and lipolysis in pasteurized fluid milk during shelf-life storage. J. Dairy Sci. 86:2491-2503.
- Ma. Y. and D. M. Barbano. 2003. Effect of temperature of CO2 injection on the pH and freezing point of milks and creams. J. Dairy Sci. 86:1578-1589.
- Ma. Y. and D. M. Barbano. 2003. Serum Protein and Casein Concentration: Effect on pH and freezing point of milk with added CO2. J. Dairy Sci. 86:1590-1600.
- Ma, Y., and D. M. Barbano. 2003. Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger. J. Dairy Sci. 86:3822-3830.
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Progress 01/01/02 to 12/31/02
Outputs
Our objectives were: (1) to measure the time for pasteurized homogenized 2 percent milk to achieve a level of lipolysis and proteolysis caused by native milk enzymes in milks of different somatic cell count (SCC) at 0.5 and 6 degrees C that would be sufficient to produce an off-flavor, (2) to determine if milk fat content (i.e., 1, 2 and 3.25 percent) influences the level of proteolysis or lipolysis caused by native milk enzymes at 6 degrees C, and (3) to determine the time in days for milks containing 2percent fat with different SCC to undergo sufficient lipolysis or proteolysis to produce an off-flavor due to the combination of the action of native milk enzymes and microbial growth at 0.5 and 6 degrees C. Based on the previous work, an off-flavor due to proteolysis was detected by 50 percent of panelists when the decrease in casein as a percentage of true protein (CN/TP) was greater than 4.76 percent. We estimated (assuming 50 percent of consumers would detect an
off-flavor when CN/TP decreases 5 percent) that pasteurized milk containing 2 percent fat would have an off-flavor at much greater than 61 and 54 d for the low SCC milk, and at about 54 and 19 d for the high SCC, at 0.5 and 6 degrees C, respectively. Previous research reported that 34 percent of panelists could detect an off-flavor in milk containing 2percent fat due to lipolysis at a (free fatty acid) FFA concentration of 0.25 meq/kg of milk. Based on these results, it can be estimated in the present study that 34 percent of panelists would detect an off-flavor in a 2 percent fat pasteurized milk with low SCC at a time long after 61 and just after 61 d at 0.5 and 6oC, respectively, while for milk with high SCC an off-flavor would be detected by 34 percent of panelist at slightly longer than 61 and 35 d at 0.5 and 6 degrees C, respectively. The combination of low SCC milk and low storage temperature when combined with processing technology to produce very low initial bacteria count in
fluid milk can produce fluid milk that will maintain flavor quality for more than 61 days.
Impacts
Previous research in our laboratory demonstrated that as milk SCC increases, cheese yield decreases and the frequency of flavor defects in cheese increases. This research had the direct impact of causing cheese manufacturers to pay dairy farmers premiums for low SCC milk. In New York State alone, this returns approximate 1 to 1.5 million extra dollars per year to dairy farmers. The present research will determine if there are similar negative impacts of high SCC milk on the use value of milk fluid milk products.
Publications
- Barbano, D. M. 2002. Effect of somatic cell count on pasteurized fluid milk quality. Pages 27-30 in the Proceedings of the National Mastitis Council, Northeast Regional Meeting. National Mastitis Council. Madison, WI.
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Progress 01/01/01 to 12/31/01
Outputs
Milk was collected and processed, and sensory evaluation was done on pasteurized 2% fat milk at 1, 7, 14, and 21 days of refrigerated shelf-life. The rate of proteolysis and lipolysis were faster in the high SCC milk during refrigerated storage. The flavor quality of the milks were comparable for the first 14 days, however after 14 days the flavor quality of the high SCC milk decreased rapidly, while the flavor quality of the low SCC milk remained high even at 21 days. A follow-up study was done in 2001 to determine the number of days until fluid milk shelf-life failure occurs due to lipolysis and proteolysis when milk SCC varies from under 100,000 to approximately 1,000,000 cells per ml.
Impacts
Previous research in our laboratory demonstrated that as milk SCC increases, cheese yield decreases and the frequency of flavor defects in cheese increases. This research had the direct impact of causing cheese manufacturers to pay dairy farmers premiums for low SCC milk. In New York State alone, this returns approximate 1 to 1.5 million extra dollars per year to dairy farmers. The present research will determine if there are similar negative impacts of high SCC milk on the use value of milk fluid milk products. If this is demonstrated, then it may provide a basis for fluid milk processors to pay bonuses to dairy farmers that produce low SCC milk and it will reduce flavor defects in fluid milk products.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs
Milk was collected and processed, and sensory evaluation was done on pasteurized 2% fat milk at 1, 7, 14, and 21 days of refrigerated shelf-life. The rate of proteolysis and lipolysis were faster in the high SCC milk during refrigerated storage. The flavor quality of the milks were comparable for the first 14 days, however after 14 days the flavor quality of the high SCC milk decreased rapidly, while the flavor quality of the low SCC milk remained high even at 21 days. A follow-up study was done in 2000 to determine the number of days until fluid milk shelf-life failure occurs due to lipolysis and proteolysis when milk SCC varies from under 100,000 to approximately 1,000,000 cells per ml.
Impacts
Previous research in our laboratory demonstrated that as milk SCC increases, cheese yield decreases and the frequency of flavor defects in cheese increases. This research had the direct impact of causing cheese manufacturers to pay dairy farmers premiums for low SCC milk. In New York State alone, this returns approximate 1 to 1.5 million extra dollars per year to dairy farmers. The present research will determine if there are similar negative impacts of high SCC milk on the use value of milk fluid milk products. If this is demonstrated, then it may provide a basis for fluid milk processors to pay bonuses to dairy farmers that produce low SCC milk and it will reduce flavor defects in fluid milk products.
Publications
- Ma, Y., C. Ryan, D. M. Barbano, D. M. Galton, M. A. Rudan, and K. J. Boor. 2000. Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk. J. Dairy Sci. 83:264-274.
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Progress 01/01/99 to 12/31/99
Outputs
Milk was collected and processed, and sensory evaluation was done on pasteurized 2% fat milk at 1, 7, 14, and 21 days of refrigerated shelf-life. The milks were tested for bacteria counts (SPC, coli, psychrotrophic bacteria, ADV, protein, casein, and flavor). A group of eight Holstein cows was sampled four times during a two week control period while they were producing milk with a SCC under 100,000 cells/ml. The milk collected within each of four different days from the 8 cows was commingled, processed. This produced four batches of control milks for evaluation. After the two week control period, two quarters for each of the same 8 cows were infected with Strep. ag. During the infection period, milk from the 8 cows was collected on four different days (approximately 800,000 SCC/ml). Again this produced four different batches of milk that were processed and evaluated to determine the impact of high milk SCC on shelf-life and quality of pasteurized, homogenized, 2% fat
milk. The rate of proteolysis and lipolysis were faster in the high SCC milk during refrigerated storage. The flavor quality of the milks were comparable for the first 14 days, however after 14 days the flavor quality of the high SCC milk decreased rapidly, while the flavor quality of the low SCC milk remained high even at 21 days. A follow-up study will be done in 2000 to determine the number of days until fluid milk shelf-life failure occurs due to lipolysis and proteolysis when milk SCC varies from under 100,000 to approximately 1,000,000 cells per ml.
Impacts
Our previous work on milk SCC had the direct impact of causing cheese manufacturers to pay dairy farmers premiums for low SCC milk. In NY State alone, this returns approx. 1 to 1.5 million extra dollars per year to dairy farmers. The present research will determine if there are similar negative impacts of high SCC milk on the use value of milk fluid milk products. If this is demonstrated, then it may provide a basis for fluid milk processors to pay bonuses to dairy farmers that produce low SCC milk and it will reduce flavor defects in fluid milk products.
Publications
- Ma, Y., C. Ryan, D. M. Barbano, D. M. Galton, M. A. Rudan, and K. J. Boor. 2000. Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk. J. Dairy Sci. 83:(in press).
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Progress 01/01/98 to 12/31/98
Outputs
Milk has been collected, processed, and sensory evaluation was be done on pasteurized 2% fat milk at 1, 7, 14, and 21 days of refrigerated shelf-life. The milks were tested for bacteria counts (SPC, coli, psychrotrophic bacteria, ADV, protein, casein, and flavor). A group of eight Holstein cows was sampled four times during a two week control period while they are producing milk with a SCC under 100,000 cells/ml. The milk collected within each of four different days from the 8 cows was commingled, processed. This produced four batches of control milks for evaluation. After the two week control period, two quarters for each of the same 8 cows were infected with Strep. ag. During the infection period, milk from the 8 cows was collected on four different days (approximately 800,000 SCC/ml). Again this produced four different batches of milk that were processed and evaluated to determine the impact of high milk SCC on shelf-life and quality of pasteurized, homogenized, 2%
fat milk. The rate of proteolysis and lipolysis were faster in the high SCC milk during refrigerated storage. The flavor quality of the milks were comparable for the first 14 days, however after 14 days the flavor quality of the high SCC milk decreased rapidly, while the flavor quality of the low SCC milk remained high even after 21 days.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 01/01/95 to 12/31/95
Outputs
Preliminary work is complete. A sensory analysis panel has been trained to evaluate milk flavor. Cows have been selected and milk processing technology has been tested for use under the conditions of the study. Milk will be collected, processed, and sensory evaluation will be done on pasteurized 2% fat milk at 1, 7, and 14 days of refrigerated shelf-life. The milks will be tested for bacteria counts (SPC, coli, psychrotrophic bacteria, ADV, protein, casein, and flavor). A group of eight Holstein cows will be sampled four times during a two week control period while they are producing milk with a SCC under 100,000 cells/ml. The milk collected within each of four different days from the 8 cows will be commingled, processed. This will produce four batches of control milks for evaluation. After the two week control period, two quarters for each of the same 8 cows will be infected with Strep. ag. During the infection period, milk from the 8 cows will be collected on four
different days (approximately 750,000 SCC/ml). Again this will produce four different batches of milk that will be processed and evaluated to determine the impact of high milk SCC on shelf-life and quality of pasteurized, homogenized, 2% fat milk.
Impacts
(N/A)
Publications
- No publications reported this period
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