Hatchery hygiene evaluation by microbiological examination of hatchery samples

This study was conducted to investigate the bacterial contamination of air and the surface of equipment and facilities in hatchery. In addition, the inhibitory effects of formaldehyde application methods on aerosol bacterial counts in the hatchers were also investigated. In the operating hatchers, the contamination of air by aerobic bacteria, coliform, and fungi was high, measuring over 300 cfu/63.6 cm(2). In the egg sorting room, contamination was moderate, whereas in the remaining sampling sites such as the setter room, candling-transfer room, and chick counting room, contamination was minimal, measuring less than 10 cfu/63.6 cm(2) for aerobic bacteria, 5 cfu/63.6 cm(2) for coliform, and 2 cfu/63.6 cm(2) for fungi. The bacterial contamination on the surface of the equipment and facilities showed similar tendencies with that of air. However, on the surfaces of the equipment and facilities in the hatcher room corridors and nonoperating hatchers where the bacterial contamination of the air was low, bacterial counts were high, measuring over 100 cfu/16 cm(2). Salmonella was mainly isolated from the hatcher rooms, chick counting room, and the related equipment and facilities but not from the areas used for the earlier processing step such as the egg receiving room, egg sorting room, setter rooms, and candling-transfer room. The Salmonella serotype that was most frequently isolated from the hatchery was Salmonella Senftenberg. The other occasional Salmonella serotypes such as Salmonella Schwarzengrund, Salmonella Madelia, Salmonella Montevideo, and Salmonella Enteritidis were isolated. The experimental group receiving formaldehyde by constant rate infusion during hatching had a significantly superior inhibitory effect on aerosol bacterial count 4 h before hatching as compared with the group receiving formaldehyde into a basin and the negative control group (P < 0.05).