Dairy
Bulk Tank Bacteria Count
Bacteria are found everywhere in our environment. The challenge for dairy farmers is to produce and sell milk with low bacteria counts in an environment that contains large numbers of bacteria. It is impossible to produce milk without some bacteria making its way into the bulk tank since bacteria are even found inside the cow's udder.
The three main factors affecting bacterial growth are a food source, temperature and water. Milk provides a perfect growth medium because of its water and nutrients. To control bacterial growth in milk, lowering the temperature below 40º F as quickly as possible after milking is essential.
Bacteria reproduce by a process called fission, or the splitting of an organism into two separate organisms. This process can occur every 15 minutes under favorable conditions. This means that high quality milk containing less than 1,000 bacteria per ml can change into poor quality milk containing more than 1,000,000 bacteria per ml in less than 5 hours if conditions are right.
Inadequate cleaning of equipment is another common cause of elevated bulk tank bacteria counts. Deposits of milk stone, dried milk, fat deposits and manure will cause bacteria to multiply rapidly and the subsequent flow of milk will carry these bacteria to the bulk tank.
Another less frequent cause of high bacteria counts is from the cow's udder. Some udder infections can shed large numbers of bacteria into the bulk tank. If enough infected cows are milked into the bulk tank, the standard plate count can become elevated.
The following guidelines will help to maintain low bacteria counts: 1) Sanitize milking equipment before each milking using a recommended sanitizer by following label directions. 2) Prepare cows for milking to avoid contaminating milk with dirt and organic material. 3) Cool milk quickly. Milk temperature must be below 40 degrees F within 2 hours after milking. 4) Rinse equipment immediately following milking with tap water. 5) Wash milking equipment using a dairy cleaner following label directions. Use hot water (140º to 160º F) for 10 to 20 minutes. The water temperature should be above 120º F at the end of the wash cycle. 6)Rinse with acidified water.
