Dairy Processing SWMS

Dairy processing combines high-energy mechanical equipment, hot pasteurising surfaces, aggressive CIP chemistry and ammonia refrigeration in a single hygienically-sealed plant — a hazard profile that sits squarely inside WHS Regulation 2025 Chapter 4. Separators spinning above 6000 rpm, homogenisers operating at 200+ bar, caustic and nitric CIP circuits at 75–85°C, and confined silos with potential oxygen-deficient atmospheres each create a distinct life-safety risk. Because the work routinely involves hazardous chemicals (Part 7.1) and confined space entry (Part 4.5), a Safe Work Method Statement is mandatory before any operator, fitter or sanitation crew commences the task. This SWMS documents the sequenced controls, isolation steps and emergency arrangements required to lawfully run, clean and maintain a fluid-milk or cheese line under the Model WHS Regulations and AS 3920 refrigeration duties.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — Remove personnel from CIP circuit operation by fully automating valve sequencing through the PLC recipe and prohibiting manual jumpering during caustic and acid phases.
2. 2Elimination — Drain, vent and confirm zero-energy state on separator bowls before any disassembly; no maintenance commences until rotation has fully ceased per AS 4024.1.
3. 3Substitution — Substitute traditional sodium hydroxide CIP with single-phase enzymatic detergent where validated by the dairy microbiologist, reducing chemical concentration and temperature exposure.
4. 4Substitution — Replace open peracetic dosing with closed-transfer pump-from-drum systems compliant with AS 3780 to eliminate manual decanting of Class 5.1 oxidisers.
5. 5Engineering — Install ammonia detection sensors at 25 ppm alarm and 150 ppm evacuation thresholds, hard-wired to plant evacuation alarms per AS 3920 and AS/NZS 1677.2.
6. 6Engineering — Provide local exhaust ventilation over pasteuriser plate-pack opening points and pressure-relief catch trays beneath CIP return manifolds to capture spray and splash.
7. 7Engineering — Apply lockout-tagout isolation points colour-coded for CIP, steam, ammonia and electrical, with captive-key interlocks on confined space silo manways.
8. 8Administrative — Issue a confined space entry permit signed by an authorised entry supervisor, with atmospheric testing for O2, CO2 and CIP residues, stand-by attendant and rescue plan rehearsed per AS 2865.
9. 9Administrative — Conduct pre-start toolbox covering this SWMS, SDS review for caustic, nitric and PAA, and verification of operator competency under WHS Reg s39 worker consultation requirements.
10. 10PPE — Wear chemical splash suit, full-face shield over indirect-vent goggles, neoprene gauntlets to elbow, and steel-cap chemical-resistant boots compliant with AS/NZS 2210.3 and AS/NZS 1337.1.

Applicable Codes of Practice

Worked example

At a regional cheese plant, the afternoon sanitation shift is preparing for a full CIP changeover between cheddar and mozzarella runs on the pasteuriser and cheese-vat circuit. The shift supervisor opens the Dairy Processing SWMS on the tablet at the pre-start huddle. Working through the hazard register, the team flags two live risks for tonight: a fitter needs to enter Silo 4 to replace an agitator seal (Category 11 confined space), and the CIP recipe will run 2% caustic at 82°C through a return line that was reported leaking on the previous shift. The supervisor matches each hazard to the controlled response — confined space permit raised, gas detector bumped, stand-by attendant nominated, and the leaking CIP return isolated and tagged out before the recipe is enabled in the PLC. Each crew member signs on against the SWMS, with the fitter additionally signing the confined space permit. Mid-task, the gas detector alarms at 25 ppm ammonia near the silo — the team stops, evacuates per the SWMS emergency arrangement, and the supervisor amends the document on the tablet to capture the deviation, the refrigeration call-out and the revised re-entry conditions. The signed-on, amended SWMS is filed to the plant WHS register for the two-year retention period.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• AS 2865 — Confined spaces

Frequently asked questions