We have a problem of spore contamination and the product cannot be heated for longer temp and longer time
Hi: you can use millipore filter 0.25 u to sterilize the product that you have if it is soluble.
Thermal processes for acid, acidified and fermented
foods are designed to destroy vegetative cells of
microorganisms capable of surviving or growing in the
product under the conditions of storage. Spores may
survive these processes, but botulinum toxin will not be
produced at a pH of 4.6 or less.
(2) Bacterial cells, yeasts, and molds are killed quickly at
boiling water temperature, but many spores of
microorganisms may survive. To reliably kill the spores
of Clostridium botulinum a high pressure steam
treatment in a retort is needed.
(3) A very dangerous situation can occur if air gets into
improperly sealed containers of acidified foods because
mold spores may germinate and grow, causing the pH to
rise above 4.6.
(4) Microbial cells do not all die at the same time during
acid and heat treatments. The more cells present
initially, the longer it will take to kill them. Therefore, it
is important to keep bacterial contamination to a
minimum.
(5) Bacteria exposed to one type of stress, such as chemical
sanitizers or heat, can become more resistant to other
stresses, such as acid and low pH.
(6) All acids are not equally effective at killing bacteria. In
general, acids become more effective as the pH is
lowered.
(7) Vegetative cells of bacteria are killed by acid more
readily as pH is lowered, and heat killing is more
effective as pH is lowered. However, many bacterial
spores will survive thermal processing at low pH, but
typically do not germinate and grow in acidified foods.
(8) Thermal processes for acidified foods must ensure that
required times and temperatures for safety are met or
exceeded at the slowest heating point in a container.
Point number (7) seven summarized the answer to your question.
That is,
7) Vegetative cells of bacteria are killed by acid more
readily as pH is lowered, and heat killing is more
effective as pH is lowered. However, many bacterial
spores will survive thermal processing at low pH, but
typically do not germinate and grow in acidified foods.
How to kill spore forming bacteria other than heating to 100 degrees? - ResearchGate. Available from: https://www.researchgate.net/post/How_to_kill_spore_forming_bacteria_other_than_heating_to_100_degrees#57603959f7b67e835b026a65 [accessed Jun 14, 2016].
Is it possible to kill spores using solvent? Like acetone or hexane? And how about extreme pH like pH 1? Or pH11? Can it reduce or kill spores? Does spore killing get confirmed? whats the test for it?
Hi! You can use tyndalization (intermittent sterilization): heat the product (to the maximum possible temperature), keep the product 24 hours (spores turn into vegetative cells). Repeat procedure 3-4 times.
In case of thermoresistant spores like Alicyclobacillus or some fungi spores you must heat to 80-90 degrees as minimum.
Spores are resistant to many chemicals. From my experience the best sporocidal effect has hydrogen peroxide (6%)+surface active substances, itaconic acid is also good
What is your product? You have mentioned that your product can not tolerate a temperature of more than 100°C, but the extreme pH you are talking about (pH 11-12 or a slow as 1-2) will kill the spores. Exposure to extreme pH leads to release of the dipicolinic acid (DPA) in parallel with spore killing.
Even treatment with ethanol also leads to same result.
Spores can be killed by some chemicals like dimethyldioxirane. You have to that which treatment can be tolerated by your product.
Obviously you can confirm the killing of the spores by providing the favourable conditions to the spores. keep positive and negative control in your test so as to check the validity of your test.
Sir any literature proof for the same? ie, for ethanol treatment and extremes of pH can kill the spores. So the spores wont re germinate?
One of the most efficient method to destroy spores is using gamma radiation. If it is available, you can expose your material to a dose of 25 kGy of gamma radiation. This dose is sufficient destroy vegetative cells as well as spores.
If the product cannot be heated for higher temperatures and longer periods of time...you may want to try irradiation if you have the facilities as suggested by others above. As they say radiation is cold sterilization....the materials can be sterilized without any heating at all
first of all, heating to 100C will only germinate the spores, NOT KILL THEM. What is the product you are having a problem with? 500 ppm chlorine can destroy spores too.
You could contact me on my personal e-mail
What is your product? If you don't use heat you have to reduce the pH of the product lower than 4.6 and keep in anaerobic condition.
method to destroy spores is using gamma radiation , ethylene oxide
chlorine is effective too. It all depends on the product which would determine the method of spore inactivation
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