Role of Water Hardness in Rinsing Bacteria from the Skin of Processed Broiler Chickens

The effect of water hardness on the ability of water to rinse bacteria from broiler skin was examined. Very hard water (total hardness = 200 ppm) was prepared by dissolving calcium chloride and magnesium chloride in distilled (soft) water and moderately hard water (total hardness =100 ppm) was prepared by diluting 1 part very hard with 1 part soft water. After five consecutive rinses of skin in soft, moderately hard, or very hard water, samples were stomached in 0.01 M potassium phosphate buffer with 0.025% ethylenediaminetetraacetic acid to recover bacteria remaining on the skin. Bacteria in stomached rinsates were enumerated on Plate Count (PC), Levine Eosine Methylene Blue (EMB), Campylobacter (CA), Pseudomonas (PS) and Staphylococci (ST) Agars. Results indicated that significantly (p<0.05) fewer bacteria were recovered on CA and PS Agars from skin rinsed in soft water than from skin rinsed in moderately or very hard water, and fewer bacteria were recovered on EMB Agar from skin rinsed in soft water than from skin rinsed in very hard water. Skin was also rinsed in very hard water that had been softened by adding 0, 1.0, 2.5, or 5.0% potassium citrate. Results indicated that fewer bacteria were recovered on EMB and CA Agars from skin rinsed in water softened with 5.0% citrate than from skin rinsed in water with 0, 1.0, or 2.5% citrate. Chemically softened water was not bactericidal. Findings indicate that reducing water hardness may increase the ability of water to remove bacteria from broiler skin.