Lavaggio dell’impianto di mungitura e qualita’ microbiologica del latte

Milking machine cleaning and microbiological quality of milk - Cleaning and
maintenance of milking equipment is essential in order to obtain high quality milk. Many
are the critical points of milking machine cleaning: water temperature, quantity and type
of detergent and water turbulence. A total of 22 farms were visited three times in order to
monitor milking machine cleaning using electronic flow meters (Lactocorder®). Cleaning
process can be divided in three phases: pre-rinse, detergent phase and post-rinse. In our
study the duration of detergent phase was 17.4±5.80 min, electrical conductivity of the
detergent solution was 4.06±1.84 mS/cm and turbulence was 25.2±13.9 %. Maximum
temperature detergent solution was on average 34.6±9.05°C, lower than the International guideline (43-77°C). The results underlines that farms using low water temperature (<35°C)
had higher standard plate count in bulk tank milk than the others (4.12 log10/CFU vs
3.93 log10/CFU; P<0.05). Detergent phase duration had interesting effects on milking machine
hygiene and bacterial quality of milk: 10 to 15 min seems to be the best time to reduce
standard plate count in milk and standard plate count, thermoduric and psychrotrophic
bacteria on milking equipment.