Investigations on microbiological quality of ground, tap and drinking water in livestock with regard to watering management and treatment with a modified peracetic acid

In a unit for fattening turkeys, the microbial quality of water from different sources (ground water, tap water and drinking water as well as deposit from drinking bowls) was analysed. In particular, the investigation was focused on changes in these parameters as effects of the water treatment with a modified peracetic acid and of different cleaning intervals of the bowls. Drinking water treatment with a modified peracetic acid (38 mg/L in tap water) led to significantly reduced counts of aerobic bacteria (cfu/mL) in tap water (log 1.40 versus 2.92), drinking water (log: 4.87 versus 6.79) and the deposit from the drinking bowls (cfu/g; log: 8.46 versus 10.1) regarding the whole fattening period. During the experimental period, the counts of coliforms (cfu/mL) were significantly lower (log: 1.90 versus 3.58) in the drinking water, whilst they were only lower by tendency in the deposit from the drinking bowls (cfu/g; log: 5.64 versus 6.50) when the modified peracetic acid was used. Drinking water treatment had no directed effect on counts of yeasts and moulds. These microorganisms were detected in the experimental group more often (no moulds were found in the control group), but the absolute number of yeasts per milliliter was higher in the control group. Also, an influence of different cleaning intervals of the bowls on counts of microorganisms (lower counts at the reduced cleaning interval) was observed whilst using peracetic acid. This was achieved in the drinking water as well as in the deposit from the drinking bowls; Differences were significant concerning the total counts of aerobic bacteria in the deposit and the counts of yeasts in the drinking water and the deposits. Zoonotic agents (Salmonella sp., Campylobacter sp.) were never detected. in general, counts of bacteria in the drinking water and the deposit in the drinking bowls were significantly higher than those in the tap water. In open drinking systems, the deposit determines the microbiological quality of the water. In periods of low water consumption (very young animals), short cleaning intervals of drinking bowls and drinking water treatment might be beneficial. Also, an interval treatment (pulsative application) with peracetic acid (disinfection -> water flush -> pause of variable length) might be useful for further reducing effects on the counts of microorganisms.