Leon the Milkman

Anything dairy-related

UHT Milk Problems

Hi, Milkfans

UHT milk translates to “Ultra High Temperature” Milk and is also known as long-life milk.

It is made by pasteurizing at something like 132-150 degrees Celsius for a second up to 15 seconds.

To prevent problems it is important that the milk is not going sour, that it has the right salt balance and that there is not too much serum proteins ( colostrum ) in the milk.

Put into practice you should get an analysis of salts in “normal” milk and what variance is allowed to test the milk against. Also make sure the farmer does not have too many cows calving at the same time to prevent high colostrum in the milk.

It is a good idea to do an Alcohol Test on the milk with an alcohol strength of 72-75% alcohol. This will give a fast and accurate indication of the heat tolerance of the particular milk.

Leon the Milkman

Density vs. Specific Gravity of Milk

By determining the specific gravity (SG) of milk the following information can be obtained.

• An indication of adulteration of milk with added water.
• If the fat percentage is available the solids-non-fat (or total solids content) of the milk can be calculated.


Specific gravity is the relationship of the mass of a specific volume of a substance to the mass of an equal volume of water at the same temperature.

Density is measured as mass per volume (g/ml) at a specific temperature.

The specific gravity of milk at 20 °C is ± 1.030 and is determined by the relative proportions of fat (SG = 0.93), water (SG = 1.0) and solids-non-fat (SG = 1.614).

Kind regards,
Leon the Milkman

Article on Yahoo, Google

Hi, Milkfans

Be sure to check out my newest article on this blog by typing “Even the milkman blogs” into either Google.com or Yahoo.com.

Be sure to claim your free Dairy Dictionary from this site or go directly to www.dairy-info.org to register and get it there.

Feel free to use it in your local publication.

Kind regards,
Leon the Milkman

2% Milk and all that…

Hi, Milkfans

The 2% in 2% milk is a measurement of the fat component by weight – 20 grams per 1 liter is fat.

Cheating to express it that way some consumers say, but we express most other food components in the same way – don’t we? 🙂
Full Cream Milk has about 3.5% fat by weight, so you save about half the calories drinking 2 %.
What you must keep in mind is that 1 liter of full cream milk has about 620 Calories – only about a 5th of what a rather sedentary male of about 175 Pounds needs to maintain his bodyweight! So drinking a liter of milk a day – and I don’t know many people that do that – does not contribute as many calories as people think.

Kind regards,
Leon the Milkman

Clean Cooperative Dairy Milk Production

Hi, Milkfans

When supplying milk to a cooperative it is of vital importance that the cooperative has a milk payment scheme according to which the farmers are paid. This is not only advantageous to the farmers, but also to the cooperative and to the consumers.

For the farmers the results of the test being done help them in managing their business and for the cooperative it means that they get what they pay for. Nobody can make an excellent product from bad raw material.

Meetings have to be held so that there can be agreement on what the specific tests will be and how much each component will impact the milk price. Usually these tests consist of Total Plate Count, Somatic Cell Count(Mastitis test) , Solids ( Fat, Protein and Lactose). Benchmarking to another dairy is of course a good idea.

Other non-qualitative factors that influence the milk price the farmers get are the distance the tankers have to drive to pick up the milk and the volume of milk supplied by the specific farmer.

This is the basics of management of paying for clean cooperative dairy milk production.

Kind regards,
Leon the Milkman

P.S. See the previous post for more on cleaning dairy equipment.

Cleaning Dairy Equipment

Hi, Milkfans

Like in life – so it is with dairy – always remember the basics!

When cleaning dairy equipment always give a cold water rinse until the water runs clear, then hot water alkaline, rinse, acid, rinse and finally sanitiser.
I still see hot water being used initially and that will definitely leave a protein deposit. Ask your mom about this – any protein stain must get as little heat as possible.

Some additional points: Clean all milk contact surfaces – If milking more than once per day; go through the whole cleaning process every time.

Bacteria come from many sources on the farm – animals, air, water, equipment, people and feed.

Check absolutely everything.

Kind regards,
Leon the Milkman

Cheesemaking Nuns!

Hi, Milkfans

Today and tomorrow I am teaching four nuns from Uganda, Africa to make Feta and Mozarella cheese!

They are a real treat to be with and are enjoying the course tremendously. Will see if I can get it right to post some pictures after the weekend. Will want to put some audio on the site as well sometime in next week.

Kind regards,


Home Cheese Making: Recipes for 75 Homemade Cheeses

Calorie vs. calorie

Hi, Milkmen and Milkmaidens

Have to do a calorie count for a product label?

Here in South Africa we use kiloJoules and the conversionfactor to get that to Calories is to devide by 4.2.
Thus 100 Cal amount to 420 kJ.

Check this difference though: calorie is the energy it takes to heat one gram of water one degree Celsius, and a Calorie(used in Food Industry) is actually a kiloCalorie(1000 Cal.) that has no relation to a calorie. :-), but is equal to 4.2 kJ.

Got it all figured,
Leon the Milkman

The Calorie King\'s 2006 Calorie, Fat & Carbohydrate Counter NutriGenie Calorie Counter for Windows

The case of Psychrotrophic bacteria

Psychrotrophic bacteria seem to be becoming the newest thorn in the side of the dairy industry. Scary bit is that we are helping them along.
“How?” do you ask?
Because of economic factors the pre-processing time of raw milk has been extended to an average of 4 days. This allows ample time for psychrotrophic, proteolytic bacteria to grow, and form heat stable enzymes. Although the psychrotrophic bacteria are easily killed off by normal pasteurization temperatures, the formed enzymes can survive UHT processes.
This causes multiple problems and we here at Elsenburg Dairy Lab have especially seen those problems on products like cottage cheese and UHT milk, more so over the past few years.
This is a group of bacteria that actually loves the cold chain, as it helps them outwit, outlast and outperform their competition. 😉
Nowadays psychotropic bacteria predominate in raw milk in the cold chain, especially Pseudomonas spp.
So much so that when the same milk is plated out and incubated at 7° C and at 30° C(as in Total Plate Count), the psychotropic growth will overtake the mesophilic growth, causing psychrotrophic counts to be higher than total plate counts.
I don’t think the methods of analysis are of much importance in this article, because there are many, ranging from microbial(determining the bacteria) and biochemical(determining the formed enzyme). Qualitative tests are of no use as we want to be able to enumerate the psychrotrophic bacteria.

The main concern I have is to raise awareness of a fast growing problem, that will only become more so in the future.

Possible solutions are the following:

1) Ask your lab to do a monthly psychrotrophic count on all farmers. This will identify
your high risk milk supply.
2) Thermising the milk to 68° C before cooling on the farm. This would have to be done with a plate heat exchanger, but would be economical at this stage, because the milk is already at body temperature(37° C) and the treated milk can run against the incoming milk to heat it and to be cooled down itself. An ice bank would also be needed to finish the cooling process. The thermising process would obviously increase the overall quality of
the milk as well, without influencing heat stability to a large degree.
3) Very rapid cooling on the farm to 2° C, instead of the usual 4° C and keeping it there until processing.
4) Using a pre-cooler at the factory to cool the milk down quickly from the 5-7 °C that it arrives at, to 2 °C.

Kind regards,
Leon the Milkman

Milk Raw?

Hi, Milkfans

Are you using milk raw? Why take the chance?

While it is true that some nutrients are detroyed to some extent during pasteurization it also makes milk much safer to drink. Remember that milk is one of the most nutritionally complete foods – not only for humans, but also for bacteria, fungi, molds, etc 😉
If you are buying raw milk and you want to make it safe without detroying a lot of nutrients, pasteurize at 65 degrees Celsius for 5 minutes.
This is easily done by placing a pot inside of another one and filling the gap in between with water and placing on the stove – -like you would when melting chocolate. The milk comes inside the centre pot with a thermometer. Afterwards cool in the sink – which should be filled with ice water.

Hope that helped,
Leon the Milkman

About Me

Welcome to my Blog!
I'm Leon the Milkman,  dairy specialist and  professional cheese experimenter.

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