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Independent Weekly
October
16, 2003
Hamburgers
with mustard flour a health and taste sensation!
by
Dharshini Nadarajah, Jung Han and Rick Holley, Department
of Food Science
It looks as though a little mustard could be the next "hot"
food ingredient to make a food safety difference.
A
research team in the Food Science Department at the University
of Manitoba is adding mustard flour to hamburger to knock
out any lurking Escherichia coli O157:H7. . If this organism
is present in undercooked or raw hamburgers, it can cause
"hamburger disease" with life threatening symptoms
in the young, old and immuno-compromised but it appears that
the chemical allyl isothiocyanate which imparts a characteristic
"hot" flavour to food, also kills bacteria.
Allyl
isothiocyanate is formed from a conversion of glucosinolate
compounds at approximately 0.5 to 1% of the mustard seed by
weight - at least in the black mustard species which is grown
extensively in Canada. Right now however, much of the prepared
mustard available commercially to the consumer and meat processor
(mustard flour is used as a binder in sausages) is processed
to prevent the formation of allyl isothiocyanate. Removal
(a.k.a. deheating) of the hot (pungent) characteristic of
mustard removes its antimicrobial activity. Our study used
"non-deheated" mustard flour which still contained
the glucosinolate unreacted with myrosinase which can form
allyl isothiocyanate upon contact with moisture.
We
added mustard flour to ground beef at final concentrations
of 5, 10 and 20% and stored the product at 4°C for 21
days and studied the effect of the treatments on total viable
bacteria and E.coli O157:H7. We found that the natural microflora
of the ground beef was unaffected by the addition of the mustard
flour, however, the treatments were highly effective in reducing
viable E.coli O157:H7. It was also postulated that other components
in the mustard flour may have synergistic roles with allyl
isothiocyanate in causing destruction of the E.coli O157:H7.
Based
on our results, it is likely that formulation of hamburgers
with 5 to 10% mustard powder will eliminate E.coli O157:H7
from ground beef contaminated at levels likely to be found
in commerce. Our research also concluded that addition of
allyl isothiocyanate extract in a concentrated form to packaged
hamburger meat was not as effective as mixing in the "hot
mustard" powder in the destruction of E.coli O157:H7.
Sensory
evaluation of the cooked ground beef showed that panelists
could distinguish untreated control samples from mustard treatments,
however, they still considered the mustard-treated meat to
be acceptable even at the 10% level.
Even
though the barbeque season is coming to a close, hamburgers
still remain a popular household food item. Ask your grocer
for "hot mustard" flour, mix it with hamburger,
enjoy the taste and savour the safety. But remember to cook
all hamburger very well - t to an internal temperature of
71°C (160°F).
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