2026/06/15 by Lorna Twomey, Ambrose Furey, Bernadette O'Brien +5
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Food Safety and Hygiene #Listeria monocytogenes in Food Safety #Milk Quality and Mastitis in Dairy Cows
paper · pdf · doi:10.1017/s0022029925101544
crossref issued 2026/06/15 · crossref published 2026/06/15 · crossref published-online 2026/06/15 · openalex publication_date 2026/06/15 · openalex created_date 2026/06/16 · crossref created 2026/06/17 · crossref deposited 2026/06/17 · openalex updated_date 2026/06/19 · crossref indexed 2026/07/30
Abstract Chlorine formed the basis of milking equipment cleaning protocols for decades on farms in the Republic of Ireland as it is an exceptional cleaning and disinfection agent but concerns around chlorine-based residues, primarily chlorate and trichloromethane led to the imposition of chlorine-free cleaning of milking equipment in 2021. In contrast to the versatility of chlorine-based cleaning protocols, chlorine-free cleaning requires the proper employment of several elements for effective cleaning: adequate hot water temperature, washing time and solution concentration. The objective of this study was to ascertain if the essential elements of chlorine-free cleaning are being employed as recommended on farms and if not, is it impacting on the delivery of farm bulk milk of a high microbiological standard, as measured by total bacteria (TBC) and thermoduric counts. Participating farms with TBC >15,000 cfu/mL were considered to produce poor quality milk from a TBC perspective, as were farms with a thermoduric count of >200 cfu/mL. A high percentage of farms were not using sufficient volumes of detergent (38%), acid (53%) and hot water with a starting temperature >75°C (69%) to achieve effective chlorine-free cleaning. Of the farms that were using insufficient volumes of chlorine-free detergent when ‘hot washing’ ( n = 39), 62% had ‘build-up’ present on the internal surfaces of claw-bowls. Moreover, the probability of having a TBC >15,000 cfu/mL (OR = 1.67) and a thermoduric count >200 cfu/mL (OR = 1.09) was numerically higher when insufficient volumes of acid were used. Approximately half the farms visited were producing low-quality milk due largely to suboptimal chlorine-free cleaning practices being employed on those farms. This research reiterates that chlorine-free cleaning will facilitate the production of high-quality milk at farm level, but it is critical that the chlorine-free washing protocols are correctly implemented.