Table 5.

Turbidity (optical density at 600 nm) of cleaning solutions recovered after applying a cleaning-in-place protocol to the fouling rig after recirculation of concentrated skim milk solutions at 30% w/w total solids at pH 6.1, 6.3, 6.5, and 6.7 on the fouling rig at 85 °C for 2 h.

	Turbidity (OD at 600 nm)
Circulated Milk pH	Water Rinse	Caustic Wash	Acid Wash
pH 6.1	2.91 ± 0.02 a	0.14 ± 0.01 a	0.76 ± 0.13 a
pH 6.3	2.91 ± 0.00 a	0.10 ± 0.02 b	0.63 ± 0.18 b
pH 6.5	2.96 ± 0.01 b	0.09 ± 0.01 b	0.31 ± 0.02 c
pH 6.7	3.27 ± 0.01 c	0.09 ± 0.01 b	0.18 ± 0.03 d

Results are the means of data from two independent trials. Mean values within a column with different superscript letters are significantly different (p < 0.05).