What’s cheese cultures all about?
Cheese culture comes in possibly as many varieties as cheese itself. Some cultures are traditional to specific cheese types and cannot or may not be changed, but for the most part we can evaluate a specific method of cheese making and interchange cultures to make it work better in regard to getting more yield, better flavor or a faster process. More yield means that we are getting more kilograms of cheese from the same kilograms of milk. Better flavor can be imparted by more proteolytic and lipolytic cultures. This means that these specific cultures have more enzymes that can break down protein and fat to aromatic and flavor compounds that is characteristic of that cheese variety. When we use fast cultures we usually save on labour as time is money and we should elso get more cheese out, since there is less time for demineralization of the curd.
From the above you can deduct that we can play around with different cultures to optimize a process and I must state that I have never been in a factory where this is not possible and where value could not be added in some way.
When you want to buy cultures it is important to find out which cultures are traditionally used in that cheese type – then have a look at the traditional process and with your cheese making knowledge you can start to make small changes. It is important in the dairy industry or and place where you are experimenting to always change one thing at a time, otherwise you might never know which change made the critical difference.
Cultures can be divided into groups according to the temperatures they work best at like thermophiles are heat loving and operate best between 37-45°C, where mesophiles are more comfortable in room temperatures and operate best at 22-35°C.
Cultures also differ in their handling of stressors in production like heat and salt. Thermophiles are usually much more sensitive to salt, so remember that it is much better to use them when salting cheese lightly and slowly in a brine solution. If you were to use the dry salting process that is traditionally used with cheddar they will be stopped in their tracks and no more or very little lactic acid will be formed after that. So if changing to a predominant mix of thermophiles in a dry salting process you must get them much closer to your final pH, as they will stop quite fast. Mesophiles are much more tolerant of salt and will continue to acidify in the same conditions.
Cheese making cultures in South Africa are usually very traditional – it is only now that people are starting to experiment with different combinations, without changing the general characteristic of a cheese variety too much to make it unrecognizable, but enough to make it different from all the rest.
Suppliers of cheese cultures in South Africa, and surely the rest of the world are picking up on these changing needs and are innovating new mixes to accommodate the cheese makers.
Dairy culture companies are thus becoming part of a rapidly changing dairy industry.
Rennet more about it – a lot more :-)
Rennet is used in the production of cheese as a milk curdling enzyme.
It converts milk casein (protein) from a soluble to an insoluble material and during this process; the rennet separates the milk into solids (curds) and liquid (whey).
The different milk coagulation systems available is natural animal rennet rennet from GMO organisms, coagulating enzymes from plant origin and coagulating enzymes from non-GMO microbial origin.
Animal is the best, but a lot of people prefer not to use it, because of religious views. The closest product is rennet from GMO origin, since chemically it is just like that of natural, animal origin, but here we also have a protesting fraction of people, because they believe this type of product will harm them in some way. They thus do not perceive this as “natural”.
Plant coagulation enzymes are not used commercially, since they are very hard to standardize and usually have a lot of side reactions that can cause off-tastes and other problems in cheese.
Microbial rennet of non-GMO origin has vastly improved and now has very few side- reactions. This rennet is used in large amounts in the world, since it is classified as Halal, Kosher and vegetarian. Technically these are not rennet, but milk coagulating enzyme. Different organisms are used to produce non-GMO microbial rennet.
Microbial rennet is a food grade enzyme system produced by the controlled fermentation for non-genetically modified Rhizomucor miehei . It contains the specific protease activity that makes it effective as a milk clotting enzyme. The rennet have been specially treated to make the enzyme thermal labile sensitive to inactivation by heat at pasteurization temperatures. Rennet can be bought in tablets and as liquid or paste.
As the economical alternative to cloned/ calf rennet, microbial rennet liquid has the same uses, process conditions and clotting time.
When buying rennet, certain characteristics need to be taken into account. This will include activity of 1:50,000 MCU/ml, form which should be a dark brown liquid, solubility (miscible with water), odorless and a specific gravity of approximately 1.14g/ml.
Rennet requires the availability of calcium ions for activity. Calcium, added as calcium chloride should be in the range of 10 to 100 grams per 100 litres of milk for optimum performance. The effect of calcium chloride concentrates on the activity of various enzyme samples and is superior to animal rennet.
Enzyme use levels are generally dictated by processing conditions, milk composition and calcium chloride concentration. In a general a rate of one half that of regular strength calf rennet can be used, but laboratory or pilot scale tests should be run to optimize dose levels.
Effective working temperature range plays a big role in performance. Calf rennet has a much narrower range of optimum working than most of the new “rennet” systems.
Due to it’s thermal labile nature, extra care should be taken when storing rennet; therefore it should be stored in sealed containers under refrigerated (4?C to 8?C) to minimize the loss of activity.
When using rennet to coagulate milk, always make sure to check the specification sheet of the product that you plan to use, to make sure that you are using it in the rifgt way to get the most out of that specific product.
http://cheesemaking.co.za/shop/10-rennet-south-africa
Rennet
Leon the Milkman
Dairy and Cheese Consultant
Cape Town, South Africa
http://cheesemaking.co.za/shop/cheese-consultancy/25-cheese-consultant.html
Interesting culture post
http://referral.experts.za.net/cheddar-cheese-culture/
Enjoy this info, dairy fans!
Regards,
Leon the Milkman
Need Cheese Consultants?
If you are a commercial cheese maker and need help:
Go have a look at www.cheeseconsultants.com
Regards,
Leon the Milkman
Sacco is Halal Certified!
My favourite culture company in the world has become Halal Certified! Jeyyy for them!!
Especially to QA Emiliano Ambrosini!!
Regards,
Leon the Milkman
Man o’ Mozarella
Leonard Majampa at work
Leonard Majampa showing how mozzarella should stretch when using the right cultures and process.
Aaahhh, job satisfaction!!!
Leonard is from RFG Porto Bello, in South Africa and will be going with four other cheese makers to France in September 2010 for 3 weeks of advanced training.
Rennet types – know them all
Hi, Milk Fans
The different types of “rennet” or milk coagulation enzymes are:
- from animal origin
- from GMO micro-organisms
- Curdling enzymes from plants
- Curdling enzymes from Non-GMO micro-organisms
Animal origin is the “mother” of rennets giving the highest yield and best taste.
Microbial rennet from GMO micro-organisms has the same chemical composition as animal, with some side reactions, but very close. The comparison is basically like artificial vitamin C and natural vitamin C.
The curdling enzymes from plants like, figs, papaya, etc. are suitable for lacto-vegetarians.
Curdling enzymes from Non-GMO organisms are generally, Kosher, Halaal, vegetarian.
South Africa
http://cheesemaking.co.za/shop/10-rennet-south-africa
Rennet
Leon the Milkman
Dairy and Cheese Consultant
Cape Town, South Africa
http://cheesemaking.co.za/shop/cheese-consultancy/25-cheese-consultant.html
Sacco Cheese and Yoghurt Cultures
Clerici-Sacco started out as Caglificio Clerici, a privately owned company manufacturing enzymes for cheese production and was originally established in 1872.
In 1984 the Italian company decided to broaden its product range and markets by purchasing Sacco and creating the Clerici-Sacco Group which is still owned by the founder’s descendants.
Thus Sacco cultures bring a long heritage of cheese production with generations of expertise to the South African Market.
An extensive list of cultures for the dairy and meat markets are available from Sacco, and specifications can be viewed on their website at saccosystem.com under products.
Some of the cheeses that are made from their cultures are Sweet Milk Cheeses like Gouda, Edam, Danbo – Hard Cheeses like Parmesan, Pecorino, Gruyere – Pasta Filata Types like Mozzarella, Provolone and Soft Cheeses like Camembert and Brie.
Many South African Champion cheese makers have found these real Italian Cultures to be superior in every category and have won awards with them.
Alizarol Test
1. ALIZAROL TEST
1.1 OBJECTIVE OF THE ALIZAROL TEST
The Alizarol test, due to its simplicity as well as its suitability to point out more than one defect of milk is a practical and well-suited procedure to test raw milk for acceptability, either on the farm or from the tanker at the factory. The main objective of the test is to indicate milk in which an unaccepted level of acidity has developed.
The stability of the protein complex in milk is destabilized by acid and therefore a positive alizarol test is also an indication of the heat stability of milk (i.e. the resistance of the protein complex against the denaturation by heat). The test is therefore also popular where the heat stability of milk proteins is of importance during processing, e.g. during the production of milk powder or UHT milk.
By adding the pH-indicator alizarine to the solution an indication of whether the milk is abnormally sour or alkaline can be obtained.
For an online training course on the alizarol test that you can use forever in your dairy business to re-train and train new employees at $45 go to:
1.2 FACTORS AFFECTING THE TEST
1.2.1 Acidity
The presence of lactic acid is the most important cause of a positive alizarol test. At the higher acid level (lower pH ) the protein suspension in milk will be less stable with the result that protein flocculation (coagulation) will occur when acid milk is mixed with alcohol.
Under normal circumstances and if the concentration of the alcohol is 68% (v/v), acidity will influence the test as indicated in Table 1.
TABLE 1 THE ALIZAROL TEST
TYPE OF MILK |
PH | %TA | FLOCCULATIONPROPERTIES | COLOUR |
| Fresh milk | 6.60 – 6.45 | 0.14 – 0.16 | None | Light purple |
| Slightly sour | 6.30 – 6.50 | 0.17 | Possibly small flakes | Brownish-pink |
| Sour | 6.00 – 6.20 | 0.18 – 0.19 | Small flakes | Brownish-pink |
| Very Sour | <6.00 | 0.20 + | Big flakes | Yellow |
| Sweet coagulation | 6.60 – 6.75 | 0.14 – 0.16 | Big flakes | Light purple |
| Mastitis | 6.80 + | N/A | Small flakes | Violet |
| Added alkaline | 6.80 + | N/A | None | Violet |
1.2.2 Mastitis
Mastitic milk differs from normal milk as regards, amongst others, the protein and mineral composition. These differences cause the casein (protein) to flocculate more readily in mastitic milk. As the pH of mastitic milk is normally higher than that of normal milk the alizarine colour will turn violet if such milk is tested.
1.2.3 Sweet curdling
Certain contaminating bacteria are capable of producing rennin like enzymes, which increase the viscosity of the milk and even flocculate casein in the absence of acid. This phenomenon is known as sweet curdling. Such milk can be identified by inoculating aseptically a small quantity there-off into sterilised milk and incubating the inoculated milk at room temperature for a day or more on which the viscosity of the milk will increase at the normal pH of fresh milk.
Large numbers of these bacteria e,g. 800,000 /ml milk was found to create a positive reaction in previously sterilised milk.
1.2.4 Mineral imbalance
Too high or to low a concentration of minerals such as calcium, phosphate and citrate will increase the ease with which casein will flocculate in the presence of alcohol.
This aspect is complex and not well define. It is well known that the addition of very small amounts of Calcium (0.2 ml M/4 Ca-acetate / 25 ml milk = 0.6g / 1 l melk ) and Magnesium (0.1 mlM/4 MgCl2 / /25 mlmilk = 0.95 g / 1l melk ) will normally result in a positive test while the addition of phosphate and citrate salts may alleviate the situation. In more extreme cases excess phosphate and citrate may however be the cause of a positive test.
Small variation e.g. 0.01% in the normal Calcium content of milk may influence the test.
It is claimed that in some instances supplementing a cows ration with mono-calcium phosphate e.g. 20 – 40 g /day / cow may improve the situation.
If a positive reaction is due to mineral imbalance a very slight souring of the milk, causing a portion of the colloidal fraction of the minerals to become soluble, may result in a negative test.
Heating of alizarol positive milk to 60°C for 30 minutes will cause partial precipitation of Ca3(PO4 ) and as result the test may turn negative.
1.2.5 Stage of laction;
The chemical composition of early and late lactation milk differs from that of normal milk
in the sense that it is characterised e,g. by higher levels of albumin, globulin and chloride.
Due to these differences the protein suspension in such milk is usually very
unstable against alcohol
Milk is normally very unstable to alcohol in early lactation, thereafter gradually becoming more stable and remaining at a fairly constant level of stability which is specific for each cow. Towards the end of lactation milks from some cows become more stable but a decrease in stability is more common.
1.2.6. Other factors that may cause alizarol positive reactions include;
- Irritation of the udder tisue.
- Infected uterus and vagina
- Aborsion
For an online training course on the alizarol test that you can use forever in your dairy business to re-train and train new employees at $45 go to:
1.3 PRINCIPLES OF THE TEST
The stability of the protein dispersion in milk is maintained by hydration (combining with water) and by the negative electrical charges on the protein particles. If either of these two factors under goes a change, the proteins will flocculate. Alcohol is a dehydrator and therefore destablises the protein. If the protein is already slightly unstable due to souring of the milk, dehydration with alcohol will lead to the precipitation of the protein in the form of flakes.
1.4 REAGENTS AND APPARATUS:
- Measuring equipment: E.g. 2 – 5ml pippettes, siringes or automatic measuring apparatus for measuring milk and alizarol.
- Test tubes, small containers or other apparatus for mixing milk and alizarol.
- Alizarol-solution: Either 68 % (v/v%) or other specified concentration (see Table 2) of ethanol with alizarin powder dissolved in the alcohol.
Alizarol must be kept in a brown bottle in a cool place.
Either methyl (white spirits ) or ethyl alcohol, standardized with water to specified concentration and containing 0.4g alizarin powder (1.2 – dioxy-anthrquinone – C14H8O4, MM 240.22, colour code: CI 58000, pH-reeks: 11.0 – 13.0). The pH of the mixture should be neutralized to 6.7 and checked regularly.
TABLE 2 APPLICATION OF DIFFERENT ALIZAROL CONCENTRATIONS
| Purpose of test | Concentration of alcohol | % Lactic acid for milk to curdle |
| To determine if milk will curdle without boiling. | 44 | 0.25 – 0.28 |
| Ordinary alcohol test. | 68 | 0.18 – 0.21 |
| More sensitive alcohol test. | 70 | 0.16 – 0.18 |
| To determine if milk can withstand high temperatures of condensing. | 75 | Milk will endure temperature treatment of 100 °C – 112 °C without curdling. |
1.5 THE PROCEDURE FOR DETERMINING PROTEIN STABILITY (ALIZAROL TEST)
(i) Equal volumes e.g. 2 or 5 ml of milk and alizarol of prescribe concentration, e.g. 70%, is mixed in a suitable container e.g. a test tube. (Equal volumes is critical for the accuracy of the test).
(ii) Mix carefully by inverting the tube once of twice.
(iii) Evaluate: – degree of flocculation, if any
– colour change
(iv) Interpretation
– If the colour remains light purple and no flocculation occurs, accept the milk.
– If the colour remains light purple and slight flocculation occurs, confirm acidity/ bacterial activity by performing one or more of the following tests:
- Clot-on-boiling
- pH and/or titratable acidity
- Resazurin test
– If the colour turns brownish-pink and flocculation occurs, reject the milk.
– If the milk has a brownish-pink colour but no flocculation occurs, determine the pH or %TA. If the results are unacceptable, that is, if they do not fall within the prescribed limits, reject the milk.
– If the colour of the milk varies from brownish-yellow to yellow, reject the milk.
– If the colour of the milk is violet but no flocculation occurs, determine the pH or %TA. If the results are unacceptable, that is, if they do not fall within the prescribed limits, reject the milk.
– NB! Take care not to interpret fat granules in cold milk for protein flocculation.
For an online training course on the alizarol test that you can use forever in your dairy business to re-train and train new employees at $45 go to:
Alizarol Test Kit Video
What is good about this alizarol test kit?
- Very small and handy
- only 400 microlitres of alizarol used per test
- Spring-loaded syringe makes sample taking easy
- Flip-cap bottle, so that cap cannot fall into milk or onto floor
- Can be washed and re-used few times to lower cost
Follow me on 