Refreezing thawed frozen food

[Joan]

Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

[Peter-Lucas]

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Who knows??? Just do it, and get back to us.
--
Peter Lucas
Brisbane
Australia

"As viscous as motor oil swirled in a swamp, redolent of burnt bell peppers
nested in by incontinent mice and a finish reminiscent of the dregs of a
stale can of Coca-Cola that someone has been using as an ashtray. Not a bad
drink, though."
Excerpt from "The Moose Turd Wine Tasting" by T. A. Nonymous

[Sunny]

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Two packs of frozen green prawns went into the garbage today (with $200
worth of other "frozen" stuff)
that partially thawed during our 19œhr power outage.
Play safe, bin them.

[Peter-Lucas]

Post by Sunny

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Two packs of frozen green prawns went into the garbage today (with $200
worth of other "frozen" stuff)
that partially thawed during our 19œhr power outage.
Play safe, bin them.

I would have just had a great big cook off!!

We had some friends close by with power that went out at 3.30pm one day,
and was back on at 1pm the next.

They just kept the freezer shut, and didn't open it at all.

We never lost power at all.
--
Peter Lucas
Brisbane
Australia

"As viscous as motor oil swirled in a swamp, redolent of burnt bell
peppers nested in by incontinent mice and a finish reminiscent of the
dregs of a stale can of Coca-Cola that someone has been using as an
ashtray. Not a bad drink, though."
Excerpt from "The Moose Turd Wine Tasting" by T. A. Nonymous

[Sunny]

Post by Peter-Lucas

Post by Sunny

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Two packs of frozen green prawns went into the garbage today (with

$200

Post by Sunny
worth of other "frozen" stuff)
that partially thawed during our 19œhr power outage.
Play safe, bin them.

I would have just had a great big cook off!!
We had some friends close by with power that went out at 3.30pm one day,
and was back on at 1pm the next.
They just kept the freezer shut, and didn't open it at all.
We never lost power at all.

We kept some vegetables and steak, but anything with mince went in the
bin.
including stacks of home made curry puffs etc.
(Too many memories of what bait layers did with left over mince) :-)
The BBQ was well used but you can only eat so much.

[AusWendy]

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Yes it IS likely to cause food poisoning. When food is frozen and or thawed
cells rupture. These cells release bacteria. Now if your food is frozen
and then thawed the amount of bacteria released is ok. But thawing,
refreezing and then thawing again is allowing too much bacteria to be
released.

It doesn't matter that you are then going to cook the food item as some
bacteria are NOT killed by high temperatures.

Aus Wendy

[Phred]

Post by AusWendy

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Yes it IS likely to cause food poisoning. When food is frozen and or thawed
cells rupture. These cells release bacteria. Now if your food is frozen
and then thawed the amount of bacteria released is ok. But thawing,
refreezing and then thawing again is allowing too much bacteria to be
released.
It doesn't matter that you are then going to cook the food item as some
bacteria are NOT killed by high temperatures.

Just nitpicking: I'm not sure that is true. The bacteria are
probably killed by high temperature (if high enough for long enough).
My understanding of the problem is that some nasty bacterial toxins
are very heat stable.

Cheers, Phred.

[AusWendy]

Post by Phred

Post by AusWendy

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Yes it IS likely to cause food poisoning. When food is frozen and or thawed
cells rupture. These cells release bacteria. Now if your food is frozen
and then thawed the amount of bacteria released is ok. But thawing,
refreezing and then thawing again is allowing too much bacteria to be
released.
It doesn't matter that you are then going to cook the food item as some
bacteria are NOT killed by high temperatures.

Just nitpicking: I'm not sure that is true. The bacteria are
probably killed by high temperature (if high enough for long enough).
My understanding of the problem is that some nasty bacterial toxins
are very heat stable.

LOL. For simplicity I wrote it as bacteria not being killed by heat rather
than the toxins. You are right to a certain extent, bacterial toxins such
as some strains of E Coli are heat resistant, also the clostridium botulinum
toxin ie the spores are also heat resistant. ALso Staphylococcus aureus
(golden staph) has about 11 heat resistant toxins. BUT some bacteria
themselves, thermophilic bacteria, thrive in high temps.

Aus Wendy

[Phred]

Post by AusWendy

Post by Phred

Post by AusWendy

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Yes it IS likely to cause food poisoning. When food is frozen and or thawed
cells rupture. These cells release bacteria. Now if your food is frozen
and then thawed the amount of bacteria released is ok. But thawing,
refreezing and then thawing again is allowing too much bacteria to be
released.
It doesn't matter that you are then going to cook the food item as some
bacteria are NOT killed by high temperatures.

Just nitpicking: I'm not sure that is true. The bacteria are
probably killed by high temperature (if high enough for long enough).
My understanding of the problem is that some nasty bacterial toxins
are very heat stable.

LOL. For simplicity I wrote it as bacteria not being killed by heat rather
than the toxins. You are right to a certain extent, bacterial toxins such
as some strains of E Coli are heat resistant, also the clostridium botulinum
toxin ie the spores are also heat resistant. ALso Staphylococcus aureus
(golden staph) has about 11 heat resistant toxins. BUT some bacteria
themselves, thermophilic bacteria, thrive in high temps.

Indeed, but I haven't yet heard of those thermophilic bacteria being
associated with food poisoning -- which is not to say it can't happen,
of course.

As a matter of interest, off the top of your head, do you have a
figure for the thermal death point of _Clostridium_ spores?

Cheers, Phred.

[AusWendy]

Post by Phred
As a matter of interest, off the top of your head, do you have a
figure for the thermal death point of _Clostridium_ spores?
Cheers, Phred.

Sorry not off the top of my head. Can I get back to you on that one? I do
know that there are many different clostridium spores and some are more
resitant to greater temperatures than others.

Aus Wendy

[Phred]

Post by AusWendy

Post by Phred
As a matter of interest, off the top of your head, do you have a
figure for the thermal death point of _Clostridium_ spores?

Sorry not off the top of my head. Can I get back to you on that one? I do

That would be good if not too much trouble for you. My own "resident
bacteriologist" recently fled the sticks here in the deep north of the
deep south for the illicit pleasures of the big smoke (Brisvegas :-).

Post by AusWendy
know that there are many different clostridium spores and some are more
resitant to greater temperatures than others.

Doesn't surprise me to hear that.

Cheers, Phred.

[Peter-Lucas]

Post by AusWendy

Post by Phred
As a matter of interest, off the top of your head, do you have a
figure for the thermal death point of _Clostridium_ spores?
Cheers, Phred.

Sorry not off the top of my head. Can I get back to you on that one?
I do know that there are many different clostridium spores and some
are more resitant to greater temperatures than others.
Aus Wendy

WIYF :-) (Wiki is your friend)

Clostridium botulinum is also used to prepare Botox, used to selectively
paralyze muscles to temporarily relieve wrinkles. It has other "off-
label" medical purposes, such as treating severe facial pain, such as
that caused by trigeminal neuralgia.

Botulin toxin produced by Clostridium botulinum is often believed to be
a potential bioweapon as it is so potent that it takes about 75
nanograms to kill a person (LD50 of 1ng/kg,[22] assuming an average
person weighs ~75kg); 500 grams of it would be enough to kill half of
the entire human population.

Clostridium botulinum is a soil bacterium. The spores can survive in
most environments and are very hard to kill. They can survive the
temperature of boiling water at sea level, thus many foods are canned
with a pressurized boil that achieves an even higher temperature,
sufficient to kill the spores.

Growth of the bacterium can be prevented by high acidity, high ratio of
dissolved sugar, high levels of oxygen, very low levels of moisture or
storage at temperatures below 38°F (type A). For example in a low acid,
canned vegetable such as green beans that are not heated hot enough to
kill the spores (i.e., a pressurized environment) may provide an oxygen
free medium for the spores to grow and produce the toxin. On the other
hand, pickles are sufficiently acidic to prevent growth; even if the
spores are present, they pose no danger to the consumer. Honey, corn
syrup, and other sweeteners may contain spores but the spores cannot
grow in a highly concentrated sugar solution; however, when a sweetener
is diluted in the low oxygen, low acid digestive system of an infant,
the spores can grow and produce toxin. As soon as infants begin eating
solid food, the digestive juices become too acidic for the bacterium to
grow.
--
Peter Lucas
Brisbane
Australia

"As viscous as motor oil swirled in a swamp, redolent of burnt bell
peppers nested in by incontinent mice and a finish reminiscent of the
dregs of a stale can of Coca-Cola that someone has been using as an
ashtray. Not a bad drink, though."
Excerpt from "The Moose Turd Wine Tasting" by T. A. Nonymous

[Jewelbar]

Indeed. The cells dont release bacteria, normal bacteria feed on the cells
and release toxins. The bacteria are dormant for as long as the food is
frozen (out of the danger zone), but the longer they are in the danger zone
(which they are whilst in the process of thawing and freezing) the more they
can multiply and the more heat stable toxins are released. It is impossible
to wash the toxins away. The food is bad, the toxins will poison.

I'd add up the value and make an insurance claim - the food is likely to be
bad.

:0/
Jade.

Post by Phred

Post by AusWendy

Post by Joan
Unfortunatley I let some frozen prawns partly thaw.
I have refrozen them but have been warned this is not advisable.
What happens?
Is it likely to cause food poisoning?
What if I really cook them well (fish stew type dish)?

Yes it IS likely to cause food poisoning. When food is frozen and or thawed
cells rupture. These cells release bacteria. Now if your food is frozen
and then thawed the amount of bacteria released is ok. But thawing,
refreezing and then thawing again is allowing too much bacteria to be
released.
It doesn't matter that you are then going to cook the food item as some
bacteria are NOT killed by high temperatures.

Just nitpicking: I'm not sure that is true. The bacteria are
probably killed by high temperature (if high enough for long enough).
My understanding of the problem is that some nasty bacterial toxins
are very heat stable.
Cheers, Phred.
--