Do I have a Biofilm?

Clean milking equipment depends on the use of approved cleaners at the appropriate strength, proper water temperatures, slugging action, and circulation times. Each one of these factors is critical to the effectiveness of any cleaning program. If conditions are less than perfect, you run the risk of buildups forming in equipment eventually leading to a dramatically increased Standard Plate Count (SPC) results.

Biofilms are buildups of bacteria, which often go undiagnosed because they are not necessarily visible to the naked eye and may only appear as a dull film on stainless steel, if at all. Bacteria from biofilms can periodically shed into the milkline and elevate SPC results. Biofilms typically form a protective layer providing resistance to traditional chemical cleaners and therefore require specialized treatment. Peracid cleaners such as Vortexx have been very effective in removing biofilms (refer to "Getting caught in the Vortexx - using peracid sanitizers" in this issue).

If you're experiencing high SPC results and think it may be a biofilm, here are some suggestions to help you make decisions on whether or not you need to use a peracid cleaner.

• First do a visual check of your equipment for cleanliness and evidence of buildups. This is best done using a flashlight when equipment is dry. Buildups of milk solids should be removed with manual cleaning or by checking and making adjustments to your wash procedures. Depending on the type of buildup, an Emergency Wash procedure may remove it. For more information on Emergency Washes refer to the fact sheet on "Troubleshooting Films & Deposits on Dairy Goat Milking Equipment", or consult with your dealer or OMAF Raw Milk Specialist. If all your equipment and practices check out acceptable and you are still experiencing a high SPC, your next step may be to consider a peracid. Dealers should provide you with detailed written instructions for using their products. Make sure you follow them carefully to achieve the best results and prevent injury.
• Raw Milk Specialists, Mike Foran, and Phillip Wilman, have conducted additional sampling of bulk tank milk in cases where a biofilm has been suspected. Samples are delivered to the Animal Health Lab, University of Guelph for culturing which identifies specific organisms present. Pseudomonas and Bacillus are some of the more common indicators of a biofilm. Tests take approximately 5 days to complete.
• Worn or cracked rubber parts are notorious for harboring bacteria. Ensure rubberware is in good condition and replaced when necessary. Refer to the article "Replacing Rubberware" in this issue for more information.
• Check your milk cooling. Milk should cool to between 1 and 4°C within an hour of finishing milking, and remain in this range between milkings. Interval agitation on bulk tanks should be set to provide a minimum of 5 minutes of agitation each hour in between milkings. Such mixing of the milk prevents warm layers from forming, and therefore a more uniform temperature is achieved throughout the tank of milk. Remember to check the bulk tank for cleanliness after it has been emptied, washed, and allowed to dry.
• Good hygiene practices are critical especially during milking time. Proper udder preparation, clean hands, clean sanitized milking equipment, and a dust-free environment are all important in preventing contamination of the milk.

High SPCs can be caused by a variety of reasons, many of which can be easily detected by the main operator. Take some time to check your system for defects or malfunctions. If you are still having problems identifying the source of high SPCs you may have a biofilm in which case you should consider using a peracid. Contact your dealer or one of the Raw Milk Specialists for advice.

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