⚙️ Filling line
Also known as: bottling line
Automatically packs milk into bottles and cartons.
A filling line is a line of machines that fills finished milk into cartons, bottles or other packages and seals them.
For pasteurised milk, the key things are hygiene and cold. Re-contamination after pasteurisation must be avoided by all means, and cold milk is pumped to buffer tanks before the filling machines. For ESL milk, the recommended temperature limit is 8 °C. Long-life milk is packed aseptically: a commercially sterile product is filled into sterilised containers, and the filling machine has an aseptic zone free of organisms that could grow in the product. Long-life products can be stored at ambient temperature for extended periods without spoiling.
The first filling machine for tetrahedron-shaped cartons was delivered by Tetra Pak in 1952 to a dairy in Lund, Sweden, to pack cream. The aseptic milk machine was unveiled in 1961 in Thun, Switzerland, and the rectangular Tetra Brik Aseptic carton was launched in 1969.
Packed milk must be shielded from daylight and artificial light, which degrade vitamins and cause off-flavours. Milk cartons usually combine paperboard with polyethylene; for a long shelf life without refrigeration, a layer of aluminium foil is added for almost complete protection against light and oxygen.
Wine
Wine bottling is the last step before the wine reaches the consumer, and the line is built mainly to keep oxygen out. Oxygen can dissolve into wine at every stage of bottling: transfer, filtration, the filler bowl, the headspace of the bottle and the closure.
That is why tanks and transfer lines are purged with an inert gas such as nitrogen or CO2 before filling, the filler bowl is covered with gas, and gas, a vacuum or liquid nitrogen is used to drive air out of the bottle headspace. Depending on the filler, filling can add 0.5–2.0 mg/L of dissolved oxygen. A recommended level of total dissolved oxygen is below 1.25 mg/L in bottled red wines and 0.6 mg/L in white, blush and rosé wines.
The closure matters too: oxygen permeation is lowest for screw caps and technical corks, intermediate for natural cork stoppers and highest for synthetic closures.
How it connects to milk
⚙️ Filling line → kind of → 🏭 Milk processing at the dairy plant → kind of → 🥛 Milk
How it connects to Wine
⚙️ Filling line ← related ← 🍷 Winemaking → kind of → 🍷 Wine
Links
- Used for
- 🔄 Filling
- Who works with it
- 🧑🔧 Maintenance engineer
- Part of
- 🏭 Milk processing at the dairy plant
- Wine and milk
- 🔄 Filling
- In other topics
- 🍷 Winemaking
Frequently asked questions
What is aseptic filling?
Packing a commercially sterile product into sterilised containers in a filling machine with an aseptic zone, free of organisms that could grow in the product. Long-life milk is packed this way.
Why must packed milk be protected from light?
Light degrades the vitamins in milk and causes off-flavours. For a long shelf life without refrigeration, cartons include an aluminium foil layer that blocks almost all light and oxygen.
What to read next
- 🧑🔧 Maintenance engineer — Sets up pasteurizers, milking machines and filling lines; pasteurization is 161 °F (≈72 °C) for 15 s (21 CFR 131.3).
- 🍷 Winemaking — Turning grapes into wine: from picking and sorting to fermentation, ageing and the bottle.
Similar
⚙️ Pasteurizer · ⚙️ Homogenizer · ⚙️ Butter churn · ⚙️ Cream separator · ⚙️ Milking machine
Sources
- Tetra Pak Dairy Processing Handbook: Pasteurized and ESL dairy products
- Tetra Pak Dairy Processing Handbook: Long-life dairy products
- Tetra Pak: Heritage (company timeline)
- T. E. Steiner, Ohio State University: Sources in the bottling line operation responsible for dissolved oxygen entry in wine