I am pleased to announce that my son won 3rd place at the California State
Science Fair in the Junior Division (6-8th grade) Microbiology section with his
breastmilk project. His abstract is below.
Bacterial Activity in Fresh & Frozen Human Milk as Compared to Cow’s Milk &
Baby Formula
Microbiology
Objectives/Goal: Human milk is the best food for human infants, but many
women work and must store their milk for later use. The objective of my project
was to measure the bacterial activity in human milk compared to cow’s milk and
formula, both fresh and after freezing for different periods of time.
Materials/Methods: The Methylene Blue dye test was used to measure the
relative aerobic bacterial content of various milks (fresh and pasteurized human
milk, fresh and pasteurized cow’s milk, and infant formula) tested fresh and
after freezing for 3, 10 and 26 days in a household freezer at approximately –
17.5°C. Each sample had a control. In this test, the more rapid the color
change, the more bacterial growth. Color change was recorded by time and
photographically up to 72 hrs at body temperature. The results of the experiment were
compared to the bacterial count and graded milks standard charts. In Phase II
additional samples frozen 4-5 months were tested and a simple home test kit
was designed.
Results: All milks tested exceeded the highest commercial standards for cow’
s milk. Human milk had the greatest resistance to aerobic bacterial growth
with no color change, except for 1 sample, for more than 72 hrs. Raw cow’s milk
had the greatest aerobic bacterial activity. Freezing had no effect on the
bacterial activity of the milks, with the exception of pasteurized cow’s milk
that increased in bacterial activity with the length of time frozen.
Conclusion/Discussion: Human milk is the best food for human infants, but
many women work and must store their milk for later use. One of the human milk
samples (frozen 10 days) changed color after only 10 hrs, indicating increased
bacterial activity, possibly due to illness in the donor or contamination
during collection or processing. A simple home test kit was designed and tested
to help mothers who may be concerned about the quality of their milk. Human
milk is the safest, best food for human infants, even when frozen for extended
periods of time.
Summary Statement: Human milk inhibits bacterial growth more than cow’s milk
or formulas, even after extended frozen storage, making it safest for infants
whose mothers need to express and store milk for later use.
Help Received in Doing Project: My mother obtained human milk samples and
helped with the graphs. My father helped me set up my experiment and helped
organize the poster board. Both parents helped edit my report.
Nancy
Nancy E. Wight MD, IBCLC, FABM, FAAP
Neonatologist, Sharp Mary Birch Hospital for Women and Children's Hospital
Medical Director, Sharp HealthCare Lactation Services
San Diego, CA
[log in to unmask]
***********************************************
To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]
The LACTNET mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software together with L-Soft's LSMTP(R)
mailer for lightning fast mail delivery. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|