Select the wash session being assessed.
Complete the information for each cycle: cycle description, cleanser/sanitiser used, the dose rate, volume of the cycle, the temperature in the wash drum at the start of the cycle, and if the cycle is recirculated then the temperature of the cleaning solution at the exit/dump point.
A simple way to estimate the water quantity required to achieve adequate surface contact and minimise thermal loss is to use a guide based on the experience of Australian-installed milking systems. This guide uses the number of milking units to calculate the volume of each cycle. It suggests an average cycle volume of 6–8 L/unit; with 6 L/unit for small milking machines (up to 20 milking units) and 8 L/unit for larger milking machines (20 units and over). An average cycle volume value is given because some wash programs specify a higher cycle volume (e.g. 10 L/unit) for the first pre-rinse cycle but a lower cycle volume (e.g. 5 L/unit) for the subsequent cycles. Cycle volumes will need adjustment to accommodate individual circumstances, such as long milk delivery lines, and cleanser/sanitiser label directions. A guide to the minimum required cycle volumes is shown in the Table below. A practical way to confirm sufficient cycle volume is to observe a recirculated cleaning cycle. When wash water is recirculated the minimum volume required is equal to the volume needed to maintain recirculation without the water pick up pipe admitting air.
When recording the chemical dose rates, note the programmed (if auto dispensing) rate or rate given on the dairy’s wash instructions and compare this with what is actually dispensed. Exercise appropriate safety when handling chemicals.
An example of wash session assessment is shown below. For each cycle to be assessed as a Pass each element – the volume, temperature (start and dump), chemical suitability, and
dose rate – must satisfy the minimum requirements of the specific wash program and the directions stated on the label of the dairy cleanser/sanitiser.
Some points to remember:
• Always measure/calculate the volume. Assumptions are often incorrect! Appendix 2 explains how to take volume measurements and perform the calculations.
• Exercise safety when measuring hot water temperatures.
• Be mindful at the time of measurement as to whether hot water has been recently drawn from the unit and if it has been replaced with cold water, thereby affecting the measurement taken.