Progress 07/01/02 to 09/30/11
Outputs
OUTPUTS: One cheese that seems to be sensitive to milk species differences is eyed-cheeses e.g., Swiss or Emmanthaler cheese. It is reported that curd firmness is closely related to the content of alphas1-casein in milk and alphas1-casein is basic to the formation of the network in the curd. Since goat milk, with low alhas1-casein and high Beta-casein, produces a soft bodied cheese with collapsed eyes, the question then is what would be the possibility for a sheep milk Swiss-type cheese. Previous studies have shown that with the high levels of alphas1-casein, sheep cheese curd is more dense or firmer than cow cheese curd. How might the denser curd impact the potential eye formation in a sheep Swiss-type cheese What would be the flavor of such a cheese To answer these questions, we decided to produce a Baby Swiss cheese from both cow milk and sheep milk to evaluate the potential for eyed cheese from sheep milk. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The primary target audience was members of the Dairy Sheep Assn. of North America (DSANA) and Wisconsin Dairy Sheep Coop (WDSC) along with any cheesemaker interested in the use of sheep milk for cheesemaking. This study was conducted to answer several questions that had arisen with several processors in dealing with sheep milk. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Sheep milk contained twice as much fat and 50% more solids than the cow milk. Casein content of sheep milk was higher than cow but the casein:fat ratio for sheep milk was lower than cow milk. Sheep milk cheese had higher fat and lower moisture than the cow milk cheese. This was the result of having sheep milk with a lower casein:fat ratio. Protein and salt concentrations were not significantly different between the two cheeses. The body of the sheep milk cheeses was much firmer than the cow milk cheeses. This was most likely due to the higher alphas1-casein and higher calcium content in sheep milk. With the denser curd, less salt was able to penetrate into the sheep cheeses during brining. At 1 mo of age, each of the cheeses was evaluated for eye formation. The cow milk Baby Swiss cheese was slightly overset with many dime-sized eyes. The body of the cheese allowed for good eye formation even though it was overset. The sheep milk cheese did not form eyes as the curd was too dense. When CO2 was formed in the cheese in the warm room, it expanded the mechanical openings to form definite slits. With high levels of alphas1-casein, the sheep curd apparently is too dense to allow for good elasticity to the curd that is needed for good eye formation. Flavor scores indicated that the sheep milk cheese never did approach an acceptable Swiss cheese flavor. The sensory panelists criticized the sheep milk cheese as lacking Swiss appearance and character and having too intense "clean barny" flavor. Results of this study have shown that eyed cheeses, e.g., Swiss and Emmenthaler, can not be produced from sheep milk. Sheep milk, with a high percentage of alphas1-casein, forms too firm a curd to allow for good elasticity needed for good eye formation. Final publications summarized the results of the past 2 years of research to complete the project.
Publications
- Wendorff, W.L. 2010. Milk quality for cheesemaking. Proc. of 16th Great Lakes Dairy Sheep Symposium, Nov. 11-13, 2010, Eau Claire, WI, pp. 79-94.
- Wendorff, W.L. 2010. Sheep milk and milk production: Processing and marketing. In Encyclopedia of Animal Science, 2nd Ed. W. Pond and A. Bell, eds., Marcel Dekker, Inc., New York, NY. pp. (in press).
- Wendorff, W.L. 2010. Sheep milk and milk production: Composition. In Encyclopedia of Animal Science, 2nd Ed.. W. Pond and A. Bell, eds., Marcel Dekker, Inc., New York, NY. pp. (in press).
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: One cheese that seems to be sensitive to milk species differences is eyed-cheeses e.g., Swiss or Emmanthaler cheese. It Is reported that curd firmness is closely related to the content of Alpha s1-casein in milk and alpha s1-casein is basic to the formation of the network in the curd. Since goat milk, with low alpha s1-casein and high Beta-casein, produces a soft bodied cheese with collapsed eyes, the question then is what would be the possibility for a sheep milk, Swiss-type cheese. Previous studies have shown that with the high levels of alpha s1-casein, sheep cheese curd is more dense or firmer than cow cheese curd. How might the denser curd impact the potential eye formation in a sheep Swiss-type cheese What would be the flavor of such a cheese To answer these questions, we decided to produce a Baby Swiss cheese from both cow milk and sheep milk to evaluate the potential for eyed cheese from sheep milk. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The primary target audience was members of the Dairy Sheep Assn. of North America (DSANA) and Wisconsin Dairy Sheep Coop (WDSC) along with any cheesemaker interested in the use of sheep milk for cheesemaking. This study was conducted to answer several questions that had arisen with several processors in dealing with sheep milk. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Sheep milk contained twice as much fat and 50% more solids than the cow milk. Casein content of sheep milk was higher than cow but the casein:fat ratio for sheep milk was lower than cow milk. Sheep milk cheese had higher fat and lower moisture than the cow milk cheese. This was the result of having sheep milk with a lower casein:fat ratio. Protein and salt concentrations were not significantly different between the two cheeses. The body of the sheep milk cheeses was much firmer than the cow milk cheeses. This was most likely due to the higher alpha s1-casein and higher calcium content in sheep milk. With the denser curd, less salt was able to penetrate into the sheep cheeses during brining. At 1 mo of age, each of the cheeses was evaluated for eye formation. The cow milk Baby Swiss cheese was slightly overset with many dime-sized eyes. The body of the cheese allowed for good eye formation even though it was overset. The sheep milk cheese did not form eyes as the curd was too dense. When CO2 was formed in the cheese in the warm room, it expanded the mechanical openings to form definite slits. With high levels of alpha s1-casein, the sheep curd apparently is too dense to allow for good elasticity to the curd that is needed for good eye formation. Flavor scores indicated that the sheep milk cheese never did approach an acceptable Swiss cheese flavor. The sensory panelists criticized the sheep milk cheese as lacking Swiss appearance and character and having too intense "clean barny" flavor. Flavor scores indicated that the sheep milk cheese never did approach an acceptable Swiss cheese flavor. The sensory panelists indicated the aged cow milk cheese was a very acceptable aged Baby Swiss cheese with a slightly soft body. They criticized the sheep milk cheese as lacking Swiss appearance and character and having too intense "clean barny" flavor. Results of this study have shown that eyed cheeses, e.g., Swiss and Emmenthaler, can not be produced from sheep milk. Sheep milk, with a high percentage of aplha s1-casein, forms too firm a curd to allow for good elasticity needed for good eye formation.
Publications
- Wendorff, W.L., G. Mode, and J.J. Jaeggi. 2009. You cant make eyed-cheeses from ewes milk. UW Dairy Pipeline, Vol. 21, No. 4, WI Center for Dairy Research, Univ. of Wisconsin-Madison.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Three facets to sheep milk research were conducted throughout this past year. The first involved evaluation of the potential for production of smear-ripened sheep milk cheese. Several cheesemakers had reported to us difficulty in trying to produce a smear-ripened sheep milk cheese. They reported difficulty in getting the smear organisms to properly grow on the surface of sheep milk cheese to produce the desired flavor and aroma of a typical smear-ripened cow milk cheese. We decided to produce traditional smear-ripened Brick cheeses from both cow milk and sheep milk to determine how a sheep milk cheese would compare to a cow milk cheese in a traditional smear-ripening process. The second phase of the research involved the potential temperature abuse of the frozen sheep milk during transit with the possibility of partial thawing and refreezing of the milk. To evaluate the impact of that type of abuse, this study was set up to evaluate that type of abuse on cheesemaking properties of the abused milk. After six weeks of frozen storage, one bag of milk was removed from the freezer and placed in the adjoining cooler at 4.4 C (40 F) for 24 hr and then refrozen. This treatment was to simulate the potential loss of temperature in a refrigerated trailer for short duration before the temperature was brought back in line with freezing temperatures. A second bag of frozen milk was removed from the freezer and placed at the ambient lab temperature of 24.4 C (76 F) for 4 hr. The milk was then placed back in the freezer and refrozen. This treatment was to represent the potential abuse of being placed on a loading dock during transit and not being transferred directly to proper freezing temperatures from the delivery truck. A third bag of frozen milk was kept in the freezer to serve as a control. After 3.5 months of frozen storage, the three bags of frozen milk were placed in a 3.3 C (38 F) cooler for two days to thaw completely and cheesemaking properties were evaluated. The third phase of research evaluated potential procedures for the proper thawing of frozen sheep milk for cheesemaking. The study included rapid and slow thawing procedures and evaluation of their impact on cheesemaking properties of the thawed milk. Results of the research have been provided to the cheese industry through our UW Dairy Pipeline technical quarterly news bulletin along with reports to the members of the Dairy Sheep Assn. of North America (DSANA) at the Annual Great Lakes Dairy Sheep Symposium. PARTICIPANTS: Yves Berger, Asst. Superintendent of the WI Agr. Exp. Station at Spooner , WI was a collaborator in the project along with several staff members of the WI Center for Dairy Research. Myron Olson, Master Cheesemaker at Chalet Cheese Coop in Monroe, WI assisted in eh smear-ripening project. This research was requested by several producer and processor members of the Dairy Sheep Assn. of North America (DSANA) and the WI Dairy Sheep Coop (WDSC). Sheep milk was provided by the WI Dairy Sheep Coop. TARGET AUDIENCES: The primary target audience was members of DSANA and WDSC along with any cheesemaker interested in the use of sheep milk for cheesemaking. The US dairy sheep industry is still in its early days of development and many cheesemakers are still trying to understand the difference in sheep milk in comparison to cow milk for cheesemaking. This study was conducted to answer several of the questions that had arisen with several processors in dealing with sheep milk. PROJECT MODIFICATIONS: This years project was multifaceted to answer several industry questions with one lot of sheep milk. Since supply of sheep milk was short in the Midwest, we were limited to <2000 lb. of milk for our studies.
Impacts
Results of the first phase of the study have shown that sheep milk components do not appear to have any significant inhibitory effect on the potential growth of smear ripening organisms on smear-ripened Brick cheese. Growth of yeasts, salt tolerant bacteria, and Brevibacterium linens were comparable on cow and sheep milk throughout the aging of Brick cheeses processed under equivalent environments. Previous reports of difficulty in growth of B. linens on sheep milk cheeses may have been a result of unfavorable environmental growth conditions. From the results of the second phase of research, it appears that some temperature abuse and refreezing of frozen sheep milk during transit may have a significant impact on the cheesemaking potential of that milk. The potential abuse at temperatures below 4 C (38 F) is not as significant as abuse at ambient conditions during transit. Based on these results, we would have the following recommendations when using frozen sheep milk for cheesemaking. For transit of frozen milk during warm weather conditions, we would recommend using that frozen milk within 2-3 months of receipt of that milk. If that frozen milk can be monitored during shipment and temperatures of -18 C (-10 F) can be maintained, quality of that milk should not be compromised. If that frozen milk has any potential for partial thawing and refreezing, we would recommend treating that milk as if it were slow-frozen and limit storage of the frozen milk to no more than 2 months after receipt before using it for cheese manufacture. Results of the third phase of research did not conclusively identify one thawing procedure that was optimum for maximum cheesemaking potential of frozen sheep milk. The slow thawing procedure at 4 C did provide the greatest concentration of soluble calcium in the milk for the most efficient coagulation of the milk and most effective syneresis of whey during the cheesemaking process. However, it did not yield any significant increase in cheese yield over the other thawing procedures. The 54.5 C thawing procedure yielded a comparable cheese yield to the slow thawing procedure but retained significantly more moisture in the final cheese. This was most likely due to partial denaturation of whey proteins in the thawing treatment and greater moisture retention by the denatured proteins. Accordingly, we would not recommend thawing frozen sheep milk in a vat pasteurizer or at process temperatures above 50 C. If a cheesemaker wants to thaw frozen sheep milk quicker than the slow thaw procedure at 4 C, we would recommend thawing the milk at 32 C. At that temperature, the coagulation and syneresis rates were only slightly decreased and the final cheese yield and moisture were not significantly different from the slow thaw procedure. This temperature is also very functional since it is close to the same temperature that would be used for manufacture of raw milk hard cheeses. However, in most cases we would recommend pasteurization of the thawed sheep milk prior to cheesemaking to eliminate potential pathogens and to inactivate the native lipases to control rancidity in the final cheese.
Publications
- Wendorff, W.L., K.B. Houck, Y.M. Berger, and M. Olson. 2008. Producing smear-ripened sheep milk cheese,is it possible UW Dairy Pipeline 20(1): 1, 4-7. Wis. Ctr. for Dairy Research, Madison, WI.
- Wendorff, W.L., M.A. Dufek, J.J. Jaeggi, Y. Peng, Y.M. Berger, and J.A. Lucey. 2008. Impact of handling and thawing on cheesemaking properties of frozen sheep milk. Proc. of 14th Great Lakes Dairy Sheep Symposium, Oct. 30-Nov. 1, 2008, Maryville, TN, pp. 35-44.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Several samples of defective eyed-cheeses were obtained from plants that felt the late blowing defect may be a result of milk from farms feeding distillers grains. All three cheeses had noticeable gas holes throughout the cheese. In all cheese samples received, Clostridium tyrobuytricum was present. Levels ranged from 2.40 X 10 2MPN/ml to > 2.40 X 105 MPN/ml on RCM-lactate broth. A total of ten distillers grain samples were obtained from the five ethanol plants operating in Wisconsin. Wet grains were stored at 7 C until analyzed, while dry grains were stored at 24 C. Only two of ten distillers grain samples contained anaerobic spores, both containing 3 MPN spores/ml. One wet distillers grain and one dried distillers grain sample from different plants contained the positive counts. To determine if possible storage of wet distillers grains under abusive summer conditions would result in potential problems, a sublot of each wet grain sample (250g) was incubated at 37 C for 5
days. This treatment was to replicate potential abusive conditions on-farm. An increase in both anaerobic spore count and confirmed C. tyrobutyricum counts were seen. Three of the five wet abuse (60%) samples had spore counts ranging from 4.00 X 100 MPN/ml and 1.50 X 101 MPN/ml. Two of these same samples (40%) also had positive presumptive results for C. tyrobutyricum, with counts of 7.20 X 100 MPN/ml and 2.40 X 101 MPN/ml.
PARTICIPANTS: Bob Kaiser of the Dept. of Dairy Science and Extension Agent for Dodge County and Kristen Houck of the Center for Dairy Research.
TARGET AUDIENCES: Dairy producers feeding distillers grains and cheesemakers using milk supplied by farmers feeding distillers grains.
Impacts
C. tyrobutyricum spores in raw milk do represent a potential problem for manufacturers of eyed cheeses. Those spores may be present in poor quality silage or contaminated grains fed to milking animals and may gain access during the milking procedure. However, with good management practices in handling feed materials, e.g., distillers grains and good sanitation procedures during the milking process, the potential for C. tyrobutyricum spores in raw milk for cheesemaking should be greatly reduced or eliminated.
Publications
- Houck, K.B., W.L. Wendorff, and R.M. Kaiser. 2007. Distillers grains can add nutrition and spores. UW Dairy Pipeline 19(1): 1, 4-6. Wis. Ctr. for Dairy Research, Madison, WI.
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Progress 01/01/06 to 12/31/06
Outputs
Progress report: Salty whey accounts for 2-5% of the whey generated during cheese manufacture. Since relatively little information is available on the composition of salty whey, this study was conducted to determine the range of analyses from commercial cheese plants. Total solids, fat, and salt content were significantly greater in the salty whey as compared to the corresponding sweet whey. True protein was significantly reduced in salty whey. Salty whey showed an increase in lactoferrin content and a decrease in -lactalbumin and -lactoglobulin content when compared to sweet whey.
Impacts
Salty whey may be a source of lactoferrin, potentially increasing its value to whey processors. However, the wide compositional variation shows salty whey is still a variable waste stream from the cheesemaking process.
Publications
- Blaschek, K., W. Wendorff, and S. Rankin. 2006. Compositional differences between industrial sources of salty and sweet whey. J.Dairy Sci. 89 (Suppl. 1): 312.
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Progress 01/01/05 to 12/31/05
Outputs
Study evaluated the effects of different pasteurization processes on the microbial populations in fluid milk. Samples pasteurized with HTST (72 or 76 C) significantly increased the amount of Bacillus spore activation over that of vat pasteurization. The majority of isolates in pasteurized milk were characterized as Bacillus mycoides and not Bacillus cereus, suggesting that this organism might be more a cause of sweet curdling of fluid milk than previously reported.
Impacts
We concluded that there was a difference in teh amount of Bacillus spp. spores that were activated at different pasteurization conditions. This study also indicated that proper refrigeration temperatures are important to extend the shelf life of milk products because rraditional pasteurization will activate Bacillus spores and allow for growth at abusive temperatures.
Publications
- Hanson, M.L., W.L. Wendorff, and K.B. Houck. 2005. Effect of heat treatment of milk on activation of Bacillus spores. J. Food Protect. 68: 1484-1486.
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Progress 01/01/04 to 12/31/04
Outputs
Studies were conducted on the shelf life of whole, 2 percent, and skim milk to determine rate of spoilage. There was no significant difference in rate of spoilage between the different milk products produced from the same load of raw milk.
Impacts
Previous reports had indicated that skim milk spoiled faster than whole milk. Current study shows that the type of milk product did not show any significant difference in spoilage pattern. This shows that good refrigeration is the key to extended shelf life of fluid milk products.
Publications
- Hanson, M.L., and W.L. Wendorff. 2004. Sitting on the shelf - skim vs. 2 percent vs. whole milk. UW Dairy Pipeline 16(3): 2-5, 9.
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Progress 01/01/03 to 12/31/03
Outputs
No additional progress to report at this time.
Impacts
Fat, casein and solids retention factors have been determined and can now be used to predict hard cheese yield from sheep milk. This will allow for improved payment programs to producers and improved effiencies within the processing plants.
Publications
- No publications reported this period
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