How a Dairy Should Choose Milk Pouch Film

A milk pouch is probably the thinnest packaging an Indian family handles every morning. It is filled at speed, dropped into crates, thrown into a delivery bag and squeezed in a fridge door. Then it has to open cleanly over a vessel.

So the short answer is this. For pasteurised milk, most dairies should buy a three-layer co-extruded polyethylene film, white on the outside with a dark layer to block light, made from virgin food-grade resin, printed on the outside face only, and sent with a test report for every lot. The micron depends on your pack size and your machine, not on what your neighbour dairy uses.

Below is how I would choose it if I were running the dairy.

Why three layers and not one?

Each layer has a different job. The outer layer takes the print and gives the pouch its shine. The middle layer adds stiffness and carries the black or dark masterbatch that keeps light out. Light gradually alters the taste of milk, which is why a plain transparent pouch is a poor choice. The inner layer is the sealing layer. It has to melt and fuse at the right temperature on your form-fill-seal machine, every few seconds, all day.

The FSSAI agrees with this structure. Its Food Safety and Standards (Packaging) Regulations, 2018 list "flexible plastic pouch made of polyethylene or polypropylene based co-extruded multilayered material" among the suggested packaging for milk and milk products (Schedule IV, compendium version of 9 Sep 2022).

The same kind of film also suits curd, oil and juice pouches, in plain or printed form.

What micron should you buy?

There is no single right number. When we quote milk film, we ask about three things before we give a micron:

1. Pack size. A 1 litre pouch carries double the weight of a 500 ml pouch, and its seals take more load when the crate is dropped.
2. Handling. Milk that travels by van to retailers in crates needs more strength than milk sold at the dairy counter.
3. Your machine. Older FSS machines with tired sealing jaws forgive less, so thin film shows its weakness faster.

For a reference point, the Indian Standard for milk pouch film, IS 11805, specifies 75 micron for a half-litre pouch and 85 micron for a 1 litre pouch. That is how the Indian Centre for Plastics in the Environment (ICPE) summarises it in its handbook, Plastics in Food Packaging. Many films on the market today run thinner than this. If a supplier offers you less, ask for the strength results that prove it still holds, such as dart impact and seal strength. A promise is not a test result.

I would rather lose an order than sell a dairy a film that is too thin for its crates. A leaking pouch comes back to us as a complaint anyway.

Here is one rule of the trade. Film is sold by the kilo, but you use it by the pouch. The same ICPE handbook works it out. One micron less gives about 9 more half-litre pouches, or 6 more 1 litre pouches, from every kilo. So compare quotes as cost per 1,000 pouches, and then add the cost of leakers. A cheap film that gives you 5 leaking pouches per 1,000 is not cheap. Count leakers for a week before and after any change. That number tells you more than any sales talk (mine included). If you want to know what decides strength inside the plant, I have written separately on how milk pouch film is made and tested.

Also write the tolerance on your purchase order, e.g. "75 micron, plus or minus 5%". A supplier who will not commit to a tolerance in writing is telling you something.

What about printing?

Two FSSAI rules matter here. Printing inks on food packaging must conform to IS 15495, and the printed surface must not come into direct contact with the food. In plain words, the print belongs on the outside of the pouch, never on the face that touches milk.

On the shop floor, test the print yourself:

1. Rub a wet thumb hard across the print 10 times. The ink should not smudge.
2. Press a strip of ordinary cello tape on the print and pull it off fast. If ink comes away on the tape, the film surface was not treated well enough for the ink to hold.
3. Smell a freshly opened roll. A strong solvent smell means the ink was not dried properly.

What paperwork should come with the film?

Ask for these before the first order, not after a complaint. I would not buy food film from anyone, including us, without them:

1. A certificate of conformity from an NABL-accredited lab for the layer that touches milk. The 2018 FSSAI regulations put this duty on the food business, i.e. on you, so you need it from your film supplier.
2. Overall migration results as per IS 9845. The FSSAI limit is 60 mg/kg or 10 mg/dm².
3. A written statement that the food-contact layers use virgin resin. The same regulations do not allow recycled plastic in contact with food until FSSAI frames standards for it.
4. A lot number and test report for every delivery.

If your dairy packs milk in plastic, you are also a brand owner under the Plastic Waste Management Rules, with EPR duties and printing requirements of your own. Your compliance person should check those for your pack.

What should you check when the rolls arrive?

This takes about 20 minutes per delivery and saves many arguments later.

1. Check each roll label for lot number, micron, width and net weight.
2. Weigh two or three rolls. The weight should match the label.
3. Measure thickness at 5 points across the width with a micrometer. Thin spots at the edges leak first.
4. Check the core size and roll diameter fit your FFS machine.
5. Run a few hundred pouches and count leakers before you release the lot to full production.
6. Keep one metre from each lot as a retention sample for at least as long as the milk is on the market.
7. Store rolls in their wrap, away from sun and heat, and use the oldest lot first.

Where we fit, honestly

Milk film is not something you can buy from a shopping cart. It is made to order for your width, micron, print and machine, and orders run in tonnes, not rolls. So you will not find it on our PackSmith store. The general films we do sell, in our plastic films range, are for wrapping and protecting goods, not for milk.

If you run a dairy, write to us with your pack size, machine make and current micron. We will tell you plainly whether you can go thinner, and whether you should not.

• Share this post: