Subject: Re: bottling garlic

From: [email-masked]
Date: 18 Mar 1996 11:35:21 GMT

Be careful with the bottling of garlic.  I can not help you with the 
colour change problem, but would like to point out that there has been a 
case descibed somewhere of botulism asociated with bottled garlic.  If the 
pH of the product exceeds 4.6, ensure that you heat process your jars to a 
minimum of Fo = 3 in the centre of the jar, and that your containers are 
hermetically sealed.  Do not only take the pH of the oil, mince/liquify 
the garlic and measure the pH.

Regards

Herman

[email-masked]

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From: John Laidler <[email-masked]>
Date: Mon, 25 Mar 1996 19:24:09 GMT

[email-masked] wrote:
> case descibed somewhere of botulism asociated with bottled garlic.  

More information on safety and discolouration can be found at http://www.dfst.csiro.au/oilvine.htm

------------------------------------------------------------------
 John Laidler                       P.O. Box 52, North Ryde
 Library, CSIRO Division of         email: [email-masked]
 Food Science and Technology       <URL:http://www.dfst.csiro.au/>
 North Ryde, N.S.W., Australia      phone: 02-887 8322

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From: dauerba@gwdgv1
Date: 25 Mar 1996 06:00:42 GMT

>the garlic and measure the pH.

A question from an amatuer: What does Fo=3 mean?
David Auerbach

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From: [email-masked] ("Tommasso Picardo")
Date: Sat, 6 Apr 1996 02:26:39 GMT

A question from an amateur: What does Fo=3 mean? David Auerbach 
Wow David a little question that's what you think.  It is to do with how 
much heat we put into a can to make it safe from all those nasty bugs who 
are out to get us.  [Have you every noticed how every time you invent a 
new process some more nasty bugs appear to come to life, for example 
forget feeding meat to herbivores i.e. cows,  Lets look at the cook and 
chill industry and analysis for (Listeria).]  Back to Fo, if I may be so 
bold this is the area of Food Technology and to copy from; Malvern 
Barnett.  J Ralph Blanchfield.  Food technology:-  Is the application of 
food science to the practical treatment of food materials so as to 
convert them into food products of the kind, quality and stability, and 
so packaged and distributed, as to meet the needs of consumers for safe, 
wholesome nutritious and attractive foods.  
WELL this is really a can of worms so to speak, but here we go, hope you 
enjoy it, if you want to take a degree in food technology this is what 
you would need to know!  To quote from (Phil Cassidy Grimsby.):  NOTE 
THIS IS A REDUCTION OF TEN PAGES SO ANY COMPLAINS SEND THEM TO ME AND I 
WILL IGNORE THEM!!!! JOKE:  You asked for it; 
1.  THE IMPORTANCE OF HEAT PROCESSING IN THE FOOD INDUSTRY; The safety 
and quality of food is dependant on the absence of contaminants 
categorised as foreign bodies, chemicals and micro-organisms.  Primarily 
the use of heat processing is aimed at reducing the risk of microbial 
contamination hazards.  Microbial contamination can exist in different 
forms; vegetative cells, spores and toxins.  When applying heat the 
processor must be aware of the particular microbial hazard of concern.  
In addition he/she must balance the effect of heat processing in 
rendering the food safe from microbial contamination and the adverse 
effect that heat processing can have on food taste, texture and 
nutritional properties.
2.THE EFFECT OF HEAT OF MICRO-ORGANISMS, 2.1 THERMAL DEATH POINT, 2.2  
TEMPERATURE/TIME PROFILE OF MICROBIAL DEATH; SUMMARISED:  micro-organisms 
are more susceptible to heat at higher temperatures, the destruction of 
micro-organisms at a given temperature is a function of time, the pattern 
of microbial destruction determined experimentally can be explained by 
destruction of reproductive capacity.  The effectiveness of microbial 
destruction is dependant upon the temperature and time of exposure to 
that temperature.  Note that the survival of micro-organisms is 
determined by removing a sample at each of the time intervals and 
carrying out a microbial determination of the viable organisms.  
Definition of viable micro-organism:-  A viable organism is one which has 
a capacity for reproduction.  2.3 QUANTIFYING AND MEASURING THERMAL 
PROCESSING.  From a graph produced it is obvious that there is a 
relationship between destruction of microbial spores and time.  If it was 
continued to the reading of the line from a graph produce it would get 
closer and closer to the x-axis or zero.  The thermal death rate or 
survivor curve of micro-organisms, plot data onto log-linear paper.  The 
relationship that would be illustrated in a logarithmic graph would be a 
straight line relationship.  From this data plotted we could calculate 
the decimal reduction time.  Decimal reduction time (D-value) is the time 
require to destroy 90% of spores. This value is equal to the number of 
minutes for the Thermal Death Rate Curve (Survivor Curve) to traverse one 
log cycle i.e. to go from 0.1 to 0.01 spores or micro-organisms 
surviving.  The D-values reflect the relative resistance of different 
organisms to destruction at a given temperature.  THE THERMAL DEATH RATE 
CURVE GRAPH, it is important to note that the D-values of a 
micro-organism or spore are specific to one temperature.  The D-value at 
80°C for (Bacillus cereus) will be different to the D-value at 90°C.   
PROBABILITY THEORY AND MICROBIAL DESTRUCTION.  The destruction of 
micro-organism and their spores follows a logarithmic relationship.  It 
is easy to understand how exposure at a given temperature for a given 
time equivalent to a D-value e.g. 0.5 minutes will result in a reduction 
of 10 spores to 1 spore.  BUT WHAT WOULD HAPPEN IF WE CONTINUED HEATING 
FOR A FURTHER TIME PERIOD OF 0.5 MINUTES WHICH CORRESPONDED TO THE 
D-VALUE?  The 1 spore would be reduced to 0.1 spore.  But there is no 
such thing as 0.1 of a spore so we use probability theory to explain the 
situation.  The chances or probability of survival is one in ten, 
therefore we consider ten cans each containing one spore.  The chances of 
survival of the ten individual spores is one in ten, thus of the ten cans 
it is likely that one can will contain a surviving spore.  The number of 
spores can be expressed as a probability of survival.  Thus 0.1 becomes a 
one chance in ten or one can in ten will have a surviving spore.  THE 
12-D PROCESS.  It is normal procedure for canned food manufactures to 
work to a probability of survival of one in a billion.  In terms of cans 
with surviving spores this means that if we opened 1,000,000,000,000 cans 
there is a probability of one can having a surviving spore.  This is 
extremely unlikely!  It is an excellent testimony to the canning industry 
that very few people have died from botulism.  Problems that have emerged 
with canned products have indicated that post-process contamination has 
occurred due to leakage of seams.   WE CAN QUANTIFY THE EFFECT OF THERMAL 
PROCESSING AT A SPECIFIC TEMPERATURE BY THE D-VALUE.  THE DESTRUCTION OF 
MICRO-ORGANISMS AND THEIR SPORES CAN BE EXPLAINED BY PROBABILITY THEORY.  
CANNED FOOD MANUFACTURERS OPERATE 12-D PROCESSES FOR (Clostridium 
botulinum) TO GIVE AN ACCEPTABLE SAFETY MARGIN.  5.2  Canning process.  
The heat treatment normally measured by a combination of temperature and 
time given during a sterilisation is called the thermal process.  The 
principle of the thermal process is that all viable micro-organisms and 
their spores, which are of public health and spoilage significance, are 
destroyed within a can or hermetically sealed container e.g. retortable 
pouch.  The required thermal process is dependant on a number of factors. 
 These factors include the type of food, the initial microbial 
contamination levels of the raw material, the pH of the food product, the 
presence of any microbial growth inhibiting agent e.g. nisin or curing 
salts.  In addition the storage conditions should be considered.  The 
majority of thermal processes are designed to give canned and sterilised 
foods extended storage, normally six months to two years at ambient 
temperatures.  Nisin is the only antibiotic permitted for use as a food 
additive in the UK.  It is not permitted in other member states of the 
European Union.  The safety of canned foods depends on careful control 
and regulation of each stage of the complete production process; Raw 
Materials, Blanching, Containers and their closure, Exhausting, Thermal 
process and Post-process Handling.  6. THERMAL PROCESS EVALUATION.  
Principle of Canning.  The principle of the canning operation is to 
hermetically seal food inside a container, apply heat to the container 
for a period of time in order to render the food sterile.  THERMAL 
PROCESSING CALCULATIONS.  Thermal calculation must be carried out to 
determine the temperature and duration of heat treatment required for 
each process.  The basis of these calculations is the destruction of the 
spores of (Clostridium botulinum), therefore calculations relate to the 
thermal resistance to these spores.   THE INPORTANCE OF (Clostridium 
botulinum).   Botulism is the most dangerous form of bacterial food 
poisoning.  Other food poisoning organisms affect the intestinal tract 
but (Clostridium botulinum)  produces a nerve toxin which is lethal in 
minute doses.  The spores of this organism are very resistant to heat.  
In the thermal process we must ensure that the spores are destroyed.  
Billions of cans are opened each year.  The occurrence of botulism from 
canned foods is very rare due to the high safety factors adopted in the 
thermal process.  However there is a risk of contamination from each 
individual can.  To quantify this risk we assume that each can is 
contaminated by one spore.  The risk from each can must be minimised and 
the statistical concept of probability is a useful basis for 
calculations.  THERMAL DEATH TIME CURVE-Z VALUES.  The Z-value reflects 
the relative resistance of micro-organisms and their spores to different 
temperatures.  The Z-value is defined as the change in temperature 
required to make a tenfold increase or decease in the D-value.  TO 
SUMMARIZE:  For process evaluation, thermal destruction data relating to 
more than one temperature is required and this is presented as the 
thermal death time curve.  The slope of the thermal death time curve is 
designated as Z and takes into account the relative resistance of spores 
to different temperatures.  THERMAL PROCESS EVALUATION.  In the thermal 
process evaluation it is necessary to measure the heat that is entering 
into a can.  The heat is measured as a combination of time and 
temperature. The temperature is recorded at the thermal centre of the 
can.  The reason for using the thermal centre is to ensure that the heat 
treatment recorded is given to the slowest part of the can to heat up.  
The total heat entering the can is a combination of the temperature/time 
profile or the total area under the time/temperature profile graph.  The 
area under the curve is equivalent to the heat that enters the can.  This 
heat effect is termed lethality.  To measure the lethality or heat going 
into a can it is necessary to have a standard.
YOHO WE HAVE GO THERE!  THE F-VALUE.  A unit of measurement has been 
devised to compare the relative sterilising potential of different heat 
processes.  The unit is equal to 1 minute at 121.1°C and is designated 
the symbol F.  The reason for using 121.1°C, which is an awkward number 
is due to the initial work in this subject area being done in °F. i.e. 
121.1°C is equal to 250°F.   {i.e. food technologist have never adapted 
to metric sad is it not.}  This unit allow us to compare the thermal 
effect of processes carried out at different temperatures.   All 
processes are made equivalent to 121.1°C.  THE FO VALUE.  The F-value 
takes into account the relative resistance of spores to destruction at 
different temperatures, characterised by a Z-value.  It is designated Fo 
when the Z-value associated is equal to 10°C.  Fo value is therefore 
specific to (Clostridium botulinum) and the most commonly used term in 
thermal process evaluation.
10 <-- Z-value Fo = F 121.1°C <--- reference temperature.
The Z-value for (Clostridium botulinum) is 10°C.  In practice we tend to 
do calculations based on (Clostridium botulinum)  because it is the most 
serious threat to public health and the term Fo is more common than F.
LETHALITY.  THE CONCEPT IS TO MEASURE THE LETHAL EFFECT OF HEAT THAT IS 
TRANSMITTED TO THE THERMAL CENTRE TO THE CAN.  THE TOTAL LETHALITY IS 
EQUIVALENT TO THE AREA UNDER THE CURVE. THE AREA UNDER A CURVE CAN BE 
COMPUTED USING CALCULUS BY INTEGRATION.  TO SUMMARIZE:  HEATING AT A 
TEMPERATURE OF 121.1°C FOR ONE MINUTE IS EQUIVALENT TO A F-VALUE OF ONE.  
THEREFORE THREE MINUTES AT 121.1°C IS EQUIVALENT TO AN F-VALUE OF THREE.  
THE SUM OF THE AREA UNDER THE CURVE IS EQUIVALENT TO THE HEAT MEASURED AS 
LETHALITY IN UNITS OF F MEASURED IN MINUTES.  THE F-VALUE ALLOWS US TO 
COMPARE DIFFERENT PROCESSES CARRIED OUT AT DIFFERENT TEMPERATURES BY 
MAKING ALL THE HEAT EQUIVALENT TO THE EFFECT AT 121.1°C.
Sorry I would have included a graph and the formula calculations but text 
does not sent it very well and I was not sure if you wanted that much 
info.  An example of when the canning industry gets is wrong:  "1978, 
four elderly people in Birmingham developed botulism after eating a 
contaminated can of Alaskan salmon.  Two of them died.  In 1989, 27 cases 
of botulism type B occurred following the consumption of hazelnut yogurt 
and one person died."  (Sprenger, R. A.  1995.  Hygiene for Management.  
Seventh edition.  (c)Highfield Publications.)  Credit where it is due 
they have killed less since 1978 than BSE and BSE has only been going 
since 1986, sorry forgot the new ten cases of CJD have not been nailed 
down to BSE yet, only a possibility, yeah lets light up another fag!
PLEASE NOTE: PRESENTED IS AN UNQUALIFIED INPUT and GRAMMAR/SPELLING NOT 
INCLUDED PLEASE FEEL FREE TO POINT OUT  ERRORS.

What kind of oil are 'they' putting on apples these days to make them so 
shiny?  How much oil is on an apple?  and what is the calorie content of 
that oil per apple?
The coat is an edible semi-permeable wax to increase storage life, 
inexpensive, simple to apply and as you have said make the product look 
shiny.  The coat has the ingredients of sucrose esters/cellulose/palm 
oil, whether it increases the calorie content I expect so but I am sure 
used in a calorie controlled diet the amount of increase would be nominal 
as it is a very thin layer.   

   _______   _______
  (__   __) (__   __)
     | |OM     | |OM
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[email-masked]

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From: [email-masked] (Joe Ames)
Date: 6 Apr 1996 11:17:38 GMT

And then the little boy said " Gee Mom, the reason I asked where I came 
>from  was because Billy said he came from Ohio.".

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From: Oz <[email-masked]>
Date: Sat, 6 Apr 1996 21:22:06 +0100

In article <[email-masked]>, J Ralph Blanchfield
<[email-masked]> writes
>On Sat, 6 Apr 1996 02:26:39 GMT, [email-masked]
>("Tommasso Picardo") wrote:
>
>>Wow David a little question that's what you think.  
>--- snip ---
>>To quote from (Phil Cassidy Grimsby.):  NOTE 
>--- gigantic snip --
>Hello Tommasso,
>You have done a good job in condensing a 10 page account, and given a
>useful lesson or reminder of the some of complex technological
>considerations involved in safe canning of low acid foods, but perhaps
>a bit "over the top" for an answer to a self-described amateur who
>asked "What does Fo = 3 mean?", or for other non-scientist subscribers
>A shorter and simpler answer for a non-technologist could be something
>like ---

Oh, I don't know, it was a good read of general interest to a lot of 
readers I would have thought. As indeed was the story of botulinic 
hazelnuts. I certainly learned something, for which I am grateful.

------------------------------- 
'Oz     "When I knew little, all was certain. The more I learnt,
        the less sure I was. Is this the uncertainty principle?"