| Performance goal: Water treatment reduces biofilm impacts from water on meat chicken farms. |
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| Description: A biofilm is a collection of organic and inorganic material amassed on a water system pipe surface. Biofilms in a drinking water distribution system can cause a wide range of water quality and operational problems. Biofilms can cause loss of disinfectant residuals, increased microbial concentrations, reduce dissolved oxygen, red or black water problems due to iron or sulphate-reducing bacteria, microbial-influenced corrosion, and reduced lifespan of materials (Characklis & Marshall, 1990). Biofilms can also influence vitamins, electrolytes, organic acids, vaccines and stabilisers, antibiotics, probiotics, etc. Microorganisms in biofilms can include bacteria (including coccoid round, rod-shaped, filamentous, and appendaged bacteria), fungi, nematodes, larvae, and Crustacea. Although viruses and Cryptosporidium do not grow in a biofilm, they can attach to biofilms after a contamination event. |
| Performance criteria: Biofilms controlled. Best practice level: 0CFU E. coli/ml based on laboratory or on-farm testing. Maximum acceptable level: 0CFU E. coli/ml based on laboratory or on-farm testing. |
| Minimum requirements |
| Water is disinfected with one of the following oxidants: chlorine, chloramine, chlorine dioxide, bromine, iodine, ozone or hydrogen peroxide. ORP disinfection of 650mV is measured at the far end of the water line (i.e. the last drinker). A disinfectant residual of 1–2ppm is achieved at the far end of the water line (i.e. the last drinker). |
| Water lines are made from materials that are resistant to biofilm formation. |
| Water line flushing is conducted after each batch. |
| Water lines are inspected monthly for biofilms. |
| If biofilms are detected or suspected in the water distribution system, water lines are sanitised using Operating procedure: Water line sanitation. |
| Best practice options |
| If biofilms are an ongoing issue in the water distribution system: Conduct water line swabbing using Operating procedure: Biofilm swabbing. Use a disinfectant that is effective against biofilm species to shock disinfect and sanitise water lines. Change primary (regular) disinfectant to one that will effectively control biofilm. |
| Drinking water distribution system (water lines, pumps, etc.) is resistant to biofilm formation. |
