Processing FAQs

What is the Processing Group at CDR?

The Processing Group at CDR is relatively new, and was formed by CDR Director John Lucey in 2012. The function of this group is to serve as a resource both internally for CDR staff and Food Science graduate students as well as externally for industry support in the broad area of dairy product processing operations, equipment selection and functioning, and guidance in new and novel product production procedures.

Who at CDR are in the Processing Group and what are their areas of expertise?

The chair of this group is Dean Sommer, Cheese and Food Technologist, who brings industry expertise in the areas of cheese manufacturing, general whey processing, and cheese shredding and packaging. CDR Director Prof. John Lucey brings international experience including specific expertise in areas including dairy protein separation technologies and functionality, process cheese manufacture, and cream cheese manufacture. Mike Molitor, the Dairy Ingredients Pilot Plant Manager, brings industry expertise in milk and whey separation technologies, membrane operation, evaporation, drying, pasteurization, manufacture of Greek yogurt, soft cheeses and soft dairy products, and general dairy process engineering. Dr. Karen Smith, Dairy Processing Technologist, brings industry experience in the areas of milk and whey separation and processing operations, including membrane fractionation, evaporation and drying, and has developed numerous technical sheets on milk and whey separation processes and mass balances.

What processing abilities does the CDR Pilot Plant have?

Processing abilities include a wide variety of membrane separations technologies including Reverse Osmosis, Nano Filtration, Ultra Filtration and Micro Filtration. Additionally, we have a pilot scale evaporator and spray dryer. Other processing functions include a pilot scale pasteurization unit, homogenizers, power blenders, and various other support equipment all designed with versatility and flexibility in mind..

How does the Processing Group support industry activities?

The pilot plant and staff are available to the industry to perform industry research trials on dairy processing activities related to membrane separation, evaporation, drying, and new and novel dairy product manufacturing processing such as concentrated yogurts. The staff are also available to the industry for troubleshooting activities, including answering industry questions by phone or e-mail, or for on-site visits to troubleshoot or generally support industry processing activities. The staff are available for on-site scale up support following proof of concept pilot plant trials.

What are some of the current areas of interest for the Dairy Processing Group?

Our staff are keenly aware of many current industry opportunities and challenges and typically work closely with industry to turn these opportunities into industry reality. Currently we have ongoing research in the area of fractionation of various types of acid whey to turn a troublesome byproduct into some potentially valuable products. We continue to work on new and novel dairy protein separation technologies including the isolation and manufacture of native whey proteins (milk derived whey proteins). Furthermore, we continue work on novel concentrated yogurt and soft dairy product manufacturing techniques.

What does it mean for a dairy product to be kosher?

Kosher products conform to the rules of kashrut or Jewish dietary law. Products that treif, or not allowed, include pork, shellfish, mixtures of meat and dairy and animal blood. Kosher milk products must be derived from kosher animals and may not be mixed with milk from a nonkosher animal. Cows, goats and sheep are kosher animals while camels and pigs are not. Several rabbinical organizations give kosher approval. Their symbol along with the letter “D” designates the product as kosher dairy.

What does it mean for a dairy product to be halal?

Halal refers to things that are permitted under Islamic law. Items that are forbidden are referred to as haram. Products that are haram include pork and pork products, alcohol and meat from improperly slaughtered animals. Milk is considered halal regardless of the animal that produced it. Enzymes from properly slaughtered animals. The symbol for a product that is halal is the crescent moon.

My products are certified both kosher and halal. What should I be looking out for to be sure that I maintain both certifications?

Although kosher and halal have many similar requirements there a couple significant differences and one important area of conflict. Both groups consider milk/whey from cows, sheep and goats acceptable. Camel and horse milk/whey are unacceptable for kosher certification. Alcohol is not acceptable for halal certification so milk/whey containing alcohol based components (such as a flavoring) are not permitted. Meat and dairy may not be mixed for milk/whey to be considered kosher. Enzymes from nonanimal sources, such as chymosin produced by cloned microbial fermentation, are generally permitted by both. An area of significant conflict are enzymes produced through slaughter of animals. An example would be a lipase extracted from a slaughtered kid or goat. Enzymes from animals are permitted by both groups as long as the animal has been properly slaughtered. Unfortunately kosher and halal slaughter process differ and are not mutually compatible, therefore, animal based enzymes may be either kosher or halal but not both. ADD IMAGE

What is involved with certifying a product as organic?

Organic milk/whey must meet regulations for organic products as defined by the United States Department of Agriculture (USDA) in the Code of Federal Regulations (CFR). Auditors are used to ensure compliance to prescribed practices. Practices are designed to ensure segregation of organic and nonorganic product within a plant and use of organic ingredients (such as defoamer) in organic milk/whey production.

ADD Image What is the difference between sweet and acid wheys?

The composition and therefore type of whey is determined when whey is removed from the curd during cheese production. Whey that drawn from the curd at a higher pH is referred to as sweet whey. Most types of cheese, including Cheddar, Mozzarella, Swiss and Brick, produce sweet whey. Whey drawn from curds that have a lower pH is known as acid whey. The acid may be from fermentation of lactose by cheese cultures or direct addition of acid to milk. Cheeses that result in acid whey include Cottage, ricotta and cream. Manufacture of industrial casein also produces acid whey. The most significant differences in the composition of sweet versus acid whey is the higher calcium and lactic acid content of acid whey.

What is involved with designating a product as “grass fed”?

The Food and Drug Administration (FDA) and United States Department of Agriculture (USDA) which oversee labeling of dairy products have no definition for grass fed and currently do not set standards for producers who make a grass fed label claim. Several other groups have established programs and standards for grass fed products. Some of these programs also require adherence to organic and non GMO standards. Among these other programs are Pennsylvania Certified Organic (PCO), American Grassfed Association (AGA), Animal Welfare Approved (AWA) and Northeast Organic Farming Association of New York (NOFA-NY).

What is whey cream?

Whey cream is the fat that is present in whey. Whey cream has a different composition as compared to the fat in milk. Whey cream actually is composed of group of lipids and often is responsible for flavor related problems in whey powders. Whey cream is the milkfat the escapes from the cheese curds and is carried away with the whey as it drains from the curds. The process of cheese manufacture favors the loss of fats that are softer, that is, fats that have a lower melting point. Whey cream also will not contain casein, has a lower ash (mineral) content and a lower viscosity as compared to milkfat. In addition, only a small percentage of the fat in whey cream is encased in milkfat globular membrane. Because milkfat globular membrane is missing the fat in whey cream will be more susceptible to oxidation and off flavor development.

Are there compositional requirements for whey that is to be processed into whey protein concentrates (WPC)?

Yes, there are requirements from the standpoint of both product quality and composition. The two most important requirements concern cheese fines and whey cream. Cheese fines are small pieces of curd that have broken away from or did not attach to the larger curds during production of the cheese. Because these particles can block the surface of the membranes used to process whey into WPC there is an upper limit for cheese fines present in the initial whey. In addition, cheese fines are not soluble in water and often will have cheese flavor both of which are undesired in WPC. A limit of less than 100 ppm cheese fines is typical. There also is an upper limit on the amount of fat that can be present in the initial whey. If too much fat is present it will not be possible to produce a WPC with the required protein content. Some typical maximum fat contents are <0.08% for 34WPC, <0.04 for 80WPC and <0.01 for WPI.

Why are thicker spacers used for spiral wound elements in some applications?

Proper operation of membrane systems centers on crossflow. Crossflow creates the turbulence that is needed during both production and cleaning. As a feed material becomes more viscous, it more difficult to maintain appropriate turbulence to limit fouling of the membrane surface. One option would be to increase the rate at which product flows across the membrane, however, this approach is limited by the increase in pressure drop across the element. Damage to the membrane due to excessive crossflow also is possible. Use of thicker spacers are one solution to the problem. The increased thickness of the spacer results in more turbulence in the product as it tumbles over the mesh. The thicker mesh is less flexible as compared to thinner mesh thereby making the thicker mesh more resistant movement and possible damage to the element. Cross flow therefore can be higher with elements having thicker retentate mesh. The negative to use of thicker spacers is there is less actual membrane area in the element because of the increased space taken up the thicker mesh as compared to thinner mesh. The reduced membrane area is offset by the increased flux that results from higher turbulence.