Why do bacteria grow in your milking plant?

Chapters

Handbook

Why do bacteria grow in your milking plant?

1 Why does milk quality matter to your payout? 2 Why do bacteria grow in your milking plant? 3 What is the difference between acid and alkali dairy detergents? 4 What makes a dairy plant wash actually work? 5 How do you build a dairy plant wash routine? 6 Which milking habits cause milk quality problems? 7 How cold does milk need to be in the vat? 8 How do you clean a milk vat properly? 9 How do you find out what caused a milk grade? 10 What do coliform, thermoduric and bactoscan grades mean? 11 How do you deep clean after manure contamination? 12 How do you spot clean a dairy plant? 13 How do you do a full dairy plant inspection? 14 How do you fully clean a milk line? 15 How do you run a hot recirculation wash? 16 How do you bomb wash a milking plant?

Bacteria are tiny single-celled organisms. You can't see them but they're everywhere. On cows. In milk. On your plant. They're even inside you.

One litre of perfectly good milk will still contain thousands of bacteria. That's normal. The trick is keeping those numbers low enough that they don't land you with a Bactoscan F or a thermoduric grade.

How fast do bacteria multiply in a dairy plant?

Bacteria reproduce by splitting in two. So, one becomes two. Two become four. Four becomes eight and so on. Under the right conditions, they can double every 20 minutes. That's exponential growth and it gets ugly, fast.

Let's say you've got just one bacterium:

After 1 hour: 8 bacteria
After 6 hours: 64
After 9 hours: 512
After 12 hours: 4,096

Now make that starting number more realistic, say 1,000 per ml. After 12 hours, you're at 4 million per ml. That's 10x worse than a Bactoscan F.

You see why it's crucial to not only get onto sorting a dreaded grade if one arises but more importantly, prevent getting one in the first place.

What makes bacteria grow, and what can you control?

Bacteria need the right conditions to grow. Here's what fuels them:

Condition	What it does	Can you control it?
Moisture	Most bugs love dampness	No
Food	Organic matter = dinner	Yes
Temperature	Cold slows growth; heat kills	Yes
pH	Extremes in acid/alkali kill them	Yes
Oxygen	Some need it, some don’t	No

Bottom line: you control the food, the temperature, and the pH. That means you can control the growth with the right detergents, cleaning routines, and hot water systems.

And here's the kicker:

If you've got a grade, you've got bacteria.

So, if a grade hits, you’ve got to find which factor is allowing bacteria to thrive. Then fix it.

What is soil in a milking plant?

There are two types of soil in your plant: mineral and organic.

What is mineral soil, and where does it build up?

Comes from your water (iron, manganese, calcium, silica)
Shows up as dullness, staining, or discolouration
Harmless to milk itself but it makes surfaces rough
Rough surfaces = bacteria paradise
Generally located at the top of the milk line and inside of the vat

What is organic soil, and why does it matter more?

This is the real threat. It's made of milk fat and protein - exactly what bacteria love to eat.

Fat deposits feel greasy and slippery
Protein deposits look like a rainbow sheen or brown stain on stainless surfaces
Generally located on vat walls, floors and upper surfaces of receiving cans at the top of the milk line, especially where the wash water is not making contact