Longitudinal study of the microbiological contamination of different sites of liquid feeding systems during 3 periods following cleaning-disinfecting.

A study has been undertaken in two herds in order to investigate the influence of cleaning and disinfecting on the microbiological contamination of the liquid feeding installation, and on its course. Every 4 weeks, a complete cleaning of liquid feeding installation (mixing tank, circuits, down pipes to pens) has been processed. Contamination produced by the system was then estimated through bacteriological analysis and ATP measurements on circulating water, originally clean, and called impression water. On systems with rest tanks, without remnants of the wet mixture, the study reveals that the contamination of EE by contact with biofilms and sediments on surfaces is the most pronounced.Microbiological controls revealed a high level of total flora (106 to 107 fcu/ml), in a growing tendency from the mixing tank towards the drop pipes. Lactic acid bacteria dominate this flora, what limits the negative aspect of such a contamination. Cleaning is very effective, giving a decrease by 2 to 3 logarithmic units of counts of total, acid lactic and coliform bacteria. But this effect is short and the feeding system quickly returns to his former level (before cleaning) after one week.