Review of various aspects of disinfection in dairy farms

A common practice and crucial step to control mastitis and maintain the high-quality of raw milk is teat disinfection which divides into pre-, immediately prior to, and post-milking. Accordingly, dipping and spraying procedures have been applied to prevent environmental and contagious mastitis as well as reduction of microbial load of raw milk. Quantitative tests such as somatic cell counts in raw milk are commonly used to monitor dramatic change of normal to sub-clinical (250000≤ cell mL-1), and clinical infected udder. It is assumed that pre-milking disinfection is a suitable strategy to tackle sub-clinical environmental mastitis whereas post-milking method is recommended to manage contiguous one. Pre-dipping effectively declines bacterial count in raw milk. Although, post-milking disinfection significantly reduces microbial contamination from liner and cleaning step, it is not effective on bacterial load from hands of milker, rinse water and used paper towel. The usage of disinfectants in major milk producer countries varies extensively, for instance more than two third of teat disinfectants in New Zealand is iodophor, followed by 15% chlorhexidine and 15% dodecylbenzene sulphonate. Iodophor has been used as pre- and post- sanitizer in concentration of 0.3% but it is allowable from 0.1-0.25% in UK. According to the regulations of the USA, Spain, and Canada, chlorhexidine can be used in the range of 0.11-0.5%, meanwhile Danish and Americans’ law regulated the usage of dodecylbenzene sulphonate in the vicinity of 2%. Hypochlorite has been taken into account as pre- and post- sanitizer from 0.1 to 4 % but regulated up to 0.2 in UK and 0.3% in US and CA. Likewise chlorhexidine, dodecylbenzene sulphonate, and quaternary ammonium compounds are used as post-milking. Bacteriocin is a teat disinfectant in France whereas slightly acidic electrolyzed water has been introduced as emerging pre- and post- sanitizer.