Dear impostervt-ga;
Thank you for allowing me an opportunity to answer your interesting
question.
Lets see; you want to know how to scientifically detect spoilage of
milk in a non-laboratory setting. Ok, at the risk of sounding
facetious (and I assure you that is not my intent) I must get this out
into the open before we proceed:
The best way to tell if your milk is spoiled is to check the SELL BY
date or EXPIRATION date on the container. If it is more than six days
beyond this stated date, you can safely assume that the milk is
spoiled or well on its way to being spoiled. CSIRO (CSIRO is
Australia's Commonwealth Scientific and Industrial Research
Organisation) and the Austrailian Food Industry Science Centre
shares these facts with us in an article published 26 October 1998
(Ref 98/251, KEEPING MILK FRESHER, LONGER):
When milk spoils before its use-by date, even when it has been
carefully stored and handled, it is usually because of the presence of
a group of cold-loving microbes called psychrotrophs, says Food
Science Australia dairy researcher Dr Heather Craven. "In health terms
these bacteria are pretty harmless, but they do pose a problem if they
get into the milk because then whole batches can go off - and dairy
companies receive complaints from consumers," she explains. "Even if
you keep the milk chilled, they can multiply from a few per millilitre
to over a million in the space of just six days. Even one microbe in a
carton of milk can cause a spoilage problem."
Thus the 6-day window. Although milk can remain edible far beyond the
expiration date in some instances, this is the earliest stage at which
the milk might become unsafe to consume. Other factors that affect the
freshness of the milk is the temperature at which it is stored and
improper handling, such as drinking directly from the carton.
But, alas, you are looking for a method and not a lesson. The long
held method of telling whether or not milk is spoiled is the look and
sniff method. If the milk has an unpleasant smell and/or if there is
any separation, the milk is considered by most to be spoiled. This
however is a matter of interpretation. Living in the US south, (and
for my sake I hope you have a sense of humor, because, after all, this
was my life experience) as a child I can recall my grandmother
sniffing the milk and calling it blinky. Blinky milk was not served
to drink because it may be bad, but it was not thrown out either.
Instead it was used for making breads such as biscuits or cornbread,
both of which cook at very high temperatures that assured the
elimination of potentially dangerous bacteria. Now, I dont know where
you are from and you may in fact think all this is rather humorous,
but different cultures see things in different ways; so you see, what
might be spoiled to you might be considered fine cooking ingredients
to others. If grandma said the milk was curdled (a southern form of
the word curd, as in cottage cheese) on the other hand, this meant
that it was sour and had not only separated but that the solids had
reformed in the bottom of the container as curds. This milk was
immediately discarded to the animals, as it was no longer considered
safe for human consumption. This was the way I was taught and I use
her method to this day as a means of testing the milk for my own
family's sake.
To answer your question: While there is no commercial litmus test or
hand-dandy test kit that you can buy in order to test your milk for
dangerous microbes, the AFISC (mentioned above) is currently working
on a project called the PsychroFast milk test that is already being
used by milk producers in Australia may, at some point become
available on the commercial market. If you are asking this question
because you had the brilliant idea that such a device on the inside of
a milk carton which would turn a certain color when the milk went bad
would net you millions of dollars, its a great idea, but not a new
one. If you invent it and put it on the market however, that will be
something new since it appears that none of the great minds before you
ever actually followed through on the concept; at least not on a
successful mass scale. Heck, as proficient as I am with grandmas
method, I might even give it a try myself.
Below you will find that I have carefully defined my search strategy
for you in the event that you need to search for more information. By
following the same type of searches that I did you may be able to
enhance the research I have provided even further. I hope you find
that that my research exceeds your expectations. If you have any
questions about my research please post a clarification request prior
to rating the answer. Otherwise, I welcome your rating and your final
comments and I look forward to working with you again in the near
future. Thank you for bringing your question to us.
Best regards;
Tutuzdad-ga
INFORMATION SOURCES
INNOVATIONS STORIES
http://www.abc.net.au/ra/elp/innovatn/inots710_a.htm
CSIRO MEDIA RELEASE
http://www.dfst.csiro.au/pr/mr98251.html
C SCIENCE
(This is in some other language but gives a visual example of how the
test might work)
http://www.c-science.com/txt/tc/te/ot/981213teotx.htm
CSIRO (Australia's Commonwealth Scientific and Industrial Research
Organisation)
http://www.csiro.au/
SEARCH STRATEGY
SEARCH ENGINE USED:
Google ://www.google.com
SEARCH TERMS USED:
Milk spoilage indicators
Milk spoilage indications
Milk spoilage indicated
Milk spoilage test
Milk spoiled test
How to tell when milk is spoiled |