Evaluation of calf milk pasteurization systems on 6 Pennsylvania dairy farms
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2010Autor
Elizondo Salazar, Jorge Alberto
Jones, C. M.
Heinrichs, Arlyn Jud
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Waste milk has been fed to calves for many years, but
concerns with bacterial contamination as well as possible
transmission of diseases have discouraged widespread use
of this feed. Pasteurization of waste milk is one option
to reduce management risk while utilizing a valuable,
low-cost, liquid feed source for calves. However, many
farms currently pasteurizing waste milk lack a system
to adequately monitor the efficiency of the process. A
study was carried out to evaluate 6 on-farm pasteurization
systems, including high-temperature, short-time
pasteurizers and low-temperature, batch pasteurizers.
Milk samples were taken pre- and postpasteurization
as well as from the calf buckets and immediately frozen
for later bacterial culture. Samples were collected twice
daily for 15 d. Milk samples were examined for standard
plate count (SPC), coagulase-negative staphylococci
count, environmental streptococci count, coliform
count, gram-negative noncoliform count, Streptococcus
agalactiae count, and Staphylococcus aureus count.
Before pasteurization, 68% of the samples had SPC
<20,000 cfu/mL, and 39% of samples contained <100
cfu/mL of coliform bacteria. After pasteurization, 96%
of samples had SPC <20,000 cfu/mL, and 92% had coliform
counts <100 cfu/mL. Bacteria counts were significantly
reduced by pasteurization, and pasteurized milk
contained acceptable numbers of bacteria in >90% of
samples. These results indicate that pasteurization can
be very effective in lowering bacterial contamination of
milk. However, bacteria numbers significantly increased
after pasteurization and, in some cases, bacteria counts
in milk fed to calves were similar to prepasteurization
levels. Milk handling after pasteurization was identified
as an important issue on the farms studied.
External link to the item
10.3168/jds.2010-3460Colecciones
- Zootecnia [369]