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String Cheese - Why do yellow/clear tough veins appear in string cheese?

The yellow/clear veins are caused by overheating resulting in loss of fat. Using rework can cause this (because of double heating). Also, if some cheese hangs up somewhere in your cooker/stretcher and then lets loose, it will also cause this. Either way, it’s an issue of low fat, often overheated cheese somewhere in the system.

If some of the cheese is exposed to too hot water (much over 160°F) for any length of time, or if the curd temperature gets too hot (much over 140°F) for too long, this might happen as well.

Annatto Cheese Color Carryover - Do you know of any cheese coloring products that don't carry over into the whey?

Both Chr. Hansens and Socius have cheese colors that don't affect the whey. One product is called White Whey (Chr. Hansens) the other Clear Whey (Socius). In both cases the Cheese color stays in the curd, and not in the whey.

Cheese with Crystals - Is it worth knowing if the calcium lactate crystals are is D or L?

It does not matter if it is L or a mix of L and D. We have seen crystals in Cheddar at 1 month of age and only the L form. There is too much calcium lactate in whatever form and the cheese is sweating due to low pH (<5.1) and or heat abuse. Any loose package (or roughed up surface) leaves a space at the package contact area to the cheese that will attract serum under those conditions and crystals will form if there is enough calcium lactate.

Can we claim that a cheese is "lactose free"?

A. Our labeling consultants formerly with FDA provided this information:

"I don't know that this approach is an agency-wide policy, but it sounds rational. What 'free' means is always a problem when there is not an established definition for 'zero' for the substance. The expectation is that none is present. I don't know that FDA has determined what 'lactose free' means, and until a definition is established, the claim could be risky. A regulator could insist that the amount of lactose present is detectable and therefore not 'zero'. It is not likely that CFSAN would support the initial position unless it was actually analytically sound, but even if the level of lactose present was acceptable under the claim, the manufacturer might have to deal with enforcement procedures until headquarters denied the request for action".

The difference between "lactose free" and "naturally lactose free" typically means this:

Lactose free- the food (milk) contained lactose (milk sugar) but the lactose was hydrolyzed to glucose and galactose so there is no detectable lactose in the food/beverage

Naturally lactose free- the food (cheese) is processed in a manner that lactose is removed in the cheese making process so there is no detectable lactose in the food/cheese

There is some risk associated with using the claim. Here is some additional information to consider.

B. Whether a "lactose free" claim can be viewed as misleading.

Whether a "lactose free" claim can be viewed as misleading would depend on many of the issues raised in Section II(A) about whether a "lactose free" claim is false. Another issue is whether labeling a particular cheese "lactose free" would imply that other brands of cheese of the same variety have lactose, when they in fact do not. This issue can be addressed by including the additional information on the label or modifying the "lactose free" claim. An example follows:

  • "Lactose free- all X (e.g. aged cheddar) cheese is lactose free"
  • "X Cheese is lactose free"

Another issue is whether labeling cheese "lactose free" may be misleading because the product is naturally "lactose free". By way of example, 21 C.F.R. § 101.62(b)(1)(i) states that products may be labeled as "fat free" if the food contains less than 0.5 grams of fat per reference amount. However, if the food contains less than that amount of fat without benefit of special processing, alteration, formulation, or reformulation, it must be labeled to disclose that fat is not usually present in the food (e.g., "broccoli, a fat free food"). This precedent suggests that if cheese contains less than 0.5 grams of fat per reference amount without benefit of special processing, alteration, formulation, or reformulation, then "lactose free" may not be a proper label. Instead, a label that states "X cheese, a lactose free food" may be more appropriate. As noted above, an additional (and more conservative) step would be to include the actual level of lactose in the cheese.

The actual amount of lactose is important for another reason: if a manufacturer relies on the fact that lactose-intolerant consumer can nevertheless tolerate 0.5 grams of lactose, he should be certain that his product does, in fact, contain this amount or less. Although USDA's Nutrient Database lists cheddar as containing only 0.07 grams of lactose per 28-gram serving [1], a table in the third edition of Handbook of Dairy Foods and Nutrition states that the same serving size contains 0.4-0.6 grams, i.e., potentially above the 0.5 gram level. [2] Thus, it is important to establish not only the amount of lactose in a particular product, but the amount in a standard or reference quantity of the product generally.

Can high salt or specialty cheeses be frozen?

Samples of various specialty cheese were purchased in triplicate from a local retail store. Two of the samples were frozen in the Babcock Dairy ice cream hardening freezer, while the third sample was held at 40F. One of each of the frozen sample varieties was taken out of the freezer after 3 weeks and thawed at 40F for about a day and a half. Then the thawed sample was compared to the refrigerated sample. Here are some things we saw:

Blue Cheese: The texture of the frozen blue cheese was noticeably different from the refrigerated sample. The frozen sample was very crumbly compared to the refrigerated blue cheese sample. Additionally, the mold color in the frozen and thawed sample was a sickly green color compared to the robust blue color of the refrigerated sample.

Blue Cheese

Feta Cheese: The frozen and thawed Feta sample was extremely crumbly. The chunk of cheese itself exhibited cracks after thawing, and even a slight handling of the thawed Feta resulted in a crumbling of the chunk.

Feta Cheese

Ricotta: The frozen and thawed tub of Ricotta exhibited a high degree of watering off, a cracking of the surface, and an undesirable and unpalatable mealy texture and mouthfeel.

Ricotta Cheese

Brie: The interior texture of frozen/thawed Brie cheese seemed to be similar to that of the refrigerated Brie. However, the white mold appearance on the surface of the frozen Brie was significantly disrupted, and appeared to have collapsed and become much thinner and spottier on the surface.


Mozzarella: Fresh mozzarella appeared not to be affected much by freezing, although the color of the frozen/thawed fresh mozzarella was slightly whiter and the flavor slightly sweeter than the refrigerated sample.

Muenster: Muenster cheese that was frozen appeared to be the least affected compared to the refrigerated Muenster.

Conclusion: In this snapshot uncontrolled look at the effects of freezing on the texture and flavor of varieties of cheese, it appears that freezing impacts some varieties dramatically while having little impact on other varieties. More controlled experimentation may need to be done to document the impacts of freezing on different varieties of cheese and to discover means of reducing the detrimental impacts on texture and flavor imparted by freezing on sensitive specialty cheese varieties.

Mozzarella and Salt Content - What is the typical range for salt to get to the desired flavor? How can we control salt so that it's consistent for every batch?

1. What is the typical range for salt to get to the desired flavor? For LMPS and WM Mozzarella loafs most plants would target a salt range of 1.5-1.7% salt. You can go a bit lower than this but once you are under 1.3% the cheese typically tastes like it lacks salt, which sometimes may cause a "flat" flavor. In a well-controlled plant, you should be able to keep your salt levels in Mozzarella cheeses like LMPS and WM within a range of +/- 0.1% of your target. Thus, if your target salt is 1.6% you should be able to achieve the vast majority of your vats with a salt content between 1.5-1.7% salt.

2. How can we control salt so that it's consistent for every batch? Let's assume that you generally get all your salt from brining. (i.e., no presalting of curd prior to the cooker stretcher). Assuming that is the case, most plants would control salt consistency by the following: Making sure the salinity of your brine is as consistent as possible throughout the day and from day to day (remember, the cheese is constantly up taking salt from the brine, so you need to replace this to keep the salinity in the brine constant). The smaller volume of bring per lb. of cheese the more important this becomes because the brine salinity will change rapidly when the cheese is introduced into the brine. Secondly, control the time the cheese blocks are in the brine. The longer the time in the brine, the more salt is taken up by the cheese. these are the 2 most important factors.

3. There are some other factors as well. I would recommend a brine salinity of approximately 85% saturation. Less than that and salt uptake is slowed. If the brine salinity is higher than 90%, you may form a hard layer on the surface of the cheese blocks which slows salt uptake. I recommend a brine temperature of 45 degrees F. I also recommend keeping some brine movement at all times. If the brine is totally quiescent, a thin layer of water forms at the surface of the cheese which slows salt uptake. So physical brine movement around the blocks of cheese will increase the rate of salt uptake. The problem most plants run into is they simply do not have enough residence time for the cheese in the brine. But if you hold the brine salinity constant, the residence time of the cheese constant, and the cheese is uniform in moisture and pH, you will achieve consistent salt levels in your cheese.

4. Again, I can’t visualize your system, but if there is too much free fat in the brine, fat can coat the surface of the cheese blocks and impede salt uptake, so that can be a problem. I’m a big advocate of UF brine cleaning systems.

5. Presalting of the curd on a table prior to cooking/stretching does work, I did this for many years at the Alto Dairy plant where I worked. If you presalt the curd you will need sufficient residence time for the salt to penetrate the curd or else, it will just wash off in the cooker stretcher. If you presalt, you must be careful and replace some of the water in the cooker stretcher with fresh water constantly or else the salt level in the stretching water gets too high and the curd will float, not a good situation. Some people put salt in their cooker stretcher, but I think it is difficult to achieve consistent cheese salt levels that way. I know of two companies that have salting units that add some salt to the curd after stretching but before molding, Johnson Industries (now part of Tetra Pack) , and Sulbana (now part of ALPMA). I have seen both units in action. They will achieve higher salt levels in your cheese, but in my opinion neither of them currently will achieve a consistent salt level within a block of cheese, instead there are pockets of high salt cheese and low salt cheese within individual blocks, so I'm not sold on these options. As you mentioned the performance of your Mozzarella is great, and I would caution you that the best performance mozzarella in my opinion is achieved without presalting. Presalting just seems to toughen the curd and negatively affect cheese functionality/pizza bakes to some extent. Don't get me wrong though, it can and is commonly done, but the best performing Mozzarella in my opinion is made without presalting.

6. At the end of the day, the most important factor in both consistency and achieving the desired level of salt in your cheese is your ability to brine the cheese for as long as is needed. If you can do this, then through controlling other factors such as I mentioned will result in consistent salt levels. If you can’t give the cheese necessary time, then you have to get creative with presalting, salting after stretching, or some other measure. But in any case, you should be able to achieve consistent salt levels in your cheese even now. They may be consistently low if you don’t have enough time, but there is no reason you shouldn’t be able to achieve consistency.

High Temperature, Non-Melting Natual Cheese - How do we make a cheese with this functionality?

When they talk about high temperature natural cheese, they really mean a non-melting cheese. As they said, they don't want the cheese to melt and flow and disappear during heating. There are 3 categories of natural cheese that typically don't melt"

1. High pH Latin American cheese such as Queso Fresco, Queso Panela, Queso Para

Freír, Queso Ranchero. Also, Juustoleipa would also fit in this category.

2. Very low pH cheeses such as Feta and Cottage Cheese.

3. Cheeses made with acid and heat, such as Ricotta, or Caribbean style Queso Blanco, or Paneer.

There are a few “tricks” that can be used to make a cheese that typically melts well to become non-melting. The most common technique is homogenization. If you homogenize you cheese milk the resultant cheese won’t melt.

It is possible to restrict, but not eliminate melt, through some other techniques. One technique is to pasteurize your milk at a high temperature, probably around 170F. This denatures some whey proteins which helps restrict melt.

Another is to make a cheese with a significantly higher pH than normal, say a Cheddar at a pH of 5.6-5.7. This will help restrict melt. Of course, all these techniques have other repercussions on the cheese body, texture and flavor.

Another is to use extremely young cheese. This cheese won’t have had much proteolysis so the melt will be restricted, but the flavor will be mild. Also, you could reduce the amount of rennet used and increase the amount of calcium chloride used to retard proteolysis and restrict melt (for a while at least).

Mark Johnson wrote a Pipeline article on this topic that may be useful.

Adding cheese into sausage adds another potential complicating factor. It is called cold melt. Typically, the moisture content (or water activity) of the meat is higher than the cheese, so when cheese is incorporated into sausage moisture migrates from the meat to the cheese causing excessive softening, called cold melt. Bill Wendorff did a lot of work on this in the past and wrote a Pipeline article on this topic.

Process cheese manufacturers historically have made melt restricted process cheeses (they term them high melt, which in this case means they don’t melt at high temperatures) for various applications. In their case, they accomplish this through their choice of emulsifying salts.

Are some cultures derived from any wheat products?

The answer is no. Historically, the only cultures that potentially had some gluten/wheat in the, were blue mold spores because they were propagated on bread. But the makers of blue mold spores switched to other media/non-gluten based to avoid this issue. So there should be no issues for cheeses made in the United States. European cheeses are a bit different in that a very few do have some gluten in them, but not from the cultures.

Clostridia- What are common sources of clostridia and how can it be avoided?

Clostridia species are spore forming bacteria that can come from your raw milk supply. They are heat tolerant, they survive pasteurization, and they can cause blowing in your cheese if their numbers get high enough. The Europeans worry about these types of bacteria in many of their aged, PDO cheeses like Parmesan because they cause late blowing in the cheese. To combat the spore formers, some PDO cheeses prohibit the feeding of silage to cows. Silage, especially moldy silage, is a prime source of Clostridia on the farm. The way it happens is if there are high numbers Clostridia in the silage, there will be high levels of Clostridia in the manure, and any contamination of manure from the udder/teats into the milk during milking will load the raw milk up with Clostridia. The other thing Europeans do is add lysozyme to their aged cheeses, which is an enzyme found in egg whites that inhibits Clostridia from growing and reproducing in cheese. However, the use of lysozyme is not legal in the U.S. for cheese. Plus, it introduces the whole egg allergen issue.

Normally the counts on Clostridia in raw milk are relatively low. However, the possibility exists that the Clostridia issue could be coming from just one of your farms. The other possibility, as Mark suggested, is that you could have a biofilm formed somewhere in your plant that is shedding Clostridia into your milk. A potential area for this is in your pasteurizer. Normally I worry about the regen areas of the pasteurizer. I know you have a tube pasteurizer, so I'm not as familiar with exactly how the heat from the pasteurized milk is regened/transferred back to your raw milk. I don't know if you have any cow water generated and used in your plant, but I would be concerned with contact of cow water with any product contact surface.

What would cause a positive test of be a root cause for Staphylococcus, Listeria, or Salmonella? Does it have anything to do with cleanliness of equipment?

That's a huge question. I'll try and give you a brief overview, but I could write a book on this topic. Also, if you are having trouble with any of these organisms, I would recommend you let us know so we can help you, these are nothing to fool around with.

First of all, all three of these are considered human pathogens, Staphylococcus aureus (but not other Staph species), Listeria monocytogenes and Listeria ivanovii (but not other Listeria species), and all Salmonella species. The FDA has a zero tolerance for either of the Listeria species or any Salmonella species, meaning if even one of any of these organisms is detected in product the product is considered adulterated and unsafe for human consumption and will need to be recalled. On the other hand, the FDA has a tolerance for Staphylococcus aureus (see below) of 10,000 CFU/g. The reason there is a tolerance for Staphylococcus aureus is that this organism does not cause an infection in humans like Listeria or Salmonella. In the case of bacteria that cause infections, it often takes just a few bacteria, and sometimes only one bacterium, to cause the infection. Conversely, Staph aureus produces a toxin in the food which makes people sick. This toxin is called a heat stable enterotoxin, which means it is not easily destroyed by heat, and it attacks people's gastrointestinal system, resulting in massive diarrhea and vomiting. And it turns out it takes about 100,000 Staph bacteria in a food to begin to produce significant amounts of this toxin, thus the FDA limit, with a built-in safety margin of 10,000 Colony Forming Units of Staph aureus per gram of food.

Prevention Methods:

1. Having appropriate foot sanitation baths

2. Having a well-designed plant (floor, walls, drains, etc.) and equipment (no hollow legs; no bad welds, no cracks in the walls of processor tanks, no rubber gaskets with cracks and splits for bacteria to live in, no equipment that isn't totally cleanable) so there aren't harborages for these bad bacteria to live and grow in

3. Isolation of the raw milk areas from the cheese production and finished product areas

4. Good filtered air flow through the plant to keep the air dry and low humidity

5. Keep the floors in the production areas as dry as possible, which keeps bacteria (and phage) from living and growing in the production environment

6. Maintaining an overall really sound good manufacturing program

7. Making certain your pasteurizer is operating correctly, with no pinholes in the plates, etc.