An evaluation of dairy product quality where chlorine-free cleaning is employed across the dairy processing chain from bacterial and chemical residue perspectives

Abstract

Chlorate is a residue of concern in the dairy industry and is linked to cleaning-in-place strategies that utilise chlorinated chemicals. Chlorine-free chemicals were adopted to minimise chlorate occurrence, but little is known about their performance. To address this, samples from single batches of commercially produced rennet casein powder and salted sweet cream butter were taken throughout their manufacturing processes. Manufacturing equipment was cleaned using chlorine-free chemicals. Samples were analysed for chlorate and total bacteria, thermoduric and spore former counts with 16S sequencing conducted on spore formers. Chlorate levels were 0.026 mg kg−1 in powder but were undetectable (<0.01 mg kg−1) in butter. Bacterial counts from butter and powder processes were ≤2.00 log10 cfu mL−1 and ≤4.00 log10 cfu mL−1, respectively. Spore formers were predominantly identified as Bacillus. This study demonstrates that satisfactory bacterial levels are achievable where chlorine-free chemicals are used for cleaning.