Does pasteurization of honey kill Clostridium botulinum?

The idea that honey should be pasteurized is truly odd. Honey has been used for centuries to dress wounds because of its antibacterial properties, and yet some people want to pasteurize it as if it might cause disease. Honey virtually never goes bad because it provides an inhospitable environment for most pathogens, yet some people want it cleaner.

Clostridium botulinum is a very common soil-borne organism that doesn’t cause problems for humans unless it is allowed to grow and produce toxins. This happens occasionally in low-acid (medium to high pH) foods that are not properly processed. Clostridium botulinum favors anaerobic conditions with a pH of about 4.6 or greater, so it sometimes is found in home-canned jars of fish, beans, mushrooms, and low-acid tomatoes.

As it turns out, the spores of Clostridium botulinum can survive in honey, but they can’t germinate, grow, or produce toxin in the highly acidic and extremely hygroscopic environment of honey. The spores just stay in the spore form. If we eat them, they go through us just as they would if they were stuck on a carrot or potato. The spores are everywhere and not a threat to humans with two exceptions—infants and individuals with compromised immune systems.

Very young children, usually during the first few months of life, have an underdeveloped intestine that sometimes allows Clostridium botulinum spores to grow within the gut and produce toxins. The condition is quite rare, but it most frequently happens after the ingestion of honey. The infant digestive system matures early and within a few months, the spores will pass straight through a child just as they do in an adult. Although the vulnerable stage is short, to be on the safe side, it is recommended that parents wait until a child is at least one year old before feeding honey.

Some people believe that if the honey is pasteurized it will be safe to give to infants. Nothing could be further from the truth. Pasteurization does nothing to botulism spores. Nothing.

Both the actual Clostridium botulinum bacteria and the toxins it produces are easily destroyed by boiling for several minutes or by holding them at lower temperatures for longer times. The spores, on the other hand, are extremely resistant. Pressure cooking at 250° F (121° C) for three minutes will kill the spores, as will other combinations of temperature, pressure, time, and acidity. At standard pressures, it could take hours of boiling to kill them.

But honey is pasteurized at much lower temperatures. Most sources I found recommended heating the honey to 145° F (63° C) for 30 minutes. Some preferred 150° (65.5° C) for 30 minutes. One suggested that the temperature be brought to 170° F (77° C) momentarily. In this environment, Clostridium botulinum spores are going to take off their little t-shirts and luxuriate in the sauna-like conditions.

The only thing that pasteurization does to honey is destroy many of the nuanced flavors and aromas, as well as many of the phytochemicals, antioxidants, and nutrients. In other words pasteurization degrades the product yet provides no clear benefit.

Rusty
HoneyBeeSuite

Comments

Carol
Reply

Rusty, Thanks for a great article on Clostridium botulinum. Few people realize that many bacteria have spore forms that will not be killed by pasturization. It is a mystery why pasturization of honey is performed at all. Thank you for such a well written blog.

Bill Castro
Reply

Great article. I wonder how many folks out there are scared of their shadow too? If we really want to become concerned, take a swab sample of our bathroom sink or floor and have an analysis done…bet there are much more dangerous spores and bacteria there than in honey…

The spring flows are under way…remember to super up!!!

Phillip
Reply

My guess is that honey is pasteurized to prevent it from crystallizing on the store shelves. Heating the honey to a certain degree does that too. I suppose someone thought why not pasteurize it while were at it so people who’ve grown up on pasteurized milk will think it’s safer.

I’ve met people who think crystallized honey is honey that’s gone bad. Just about any product sold in a clear container has had its appearance artificially enhanced or has had a meaningless label put on it that gives it more appeal to the general public. So much in marketing is based on appearance, not facts.

zeba
Reply

Honey is pasteurized to prevent if from fermentation. Honey has yeast and yeast spore which may cause fermentation of honey which is not desirable. Moreover, the low treatment also help to reduce the moisture in honey.

Rusty
Reply

Zeba,

Properly cured and extracted honey will not ferment and does not need pasteurization; it is one of the properties of honey that mankind has marveled over for centuries. Mold and yeast spores cannot germinate in properly cured honey because it is too hygroscopic. The high sugar content literally sucks the moisture away.

If your honey is fermenting, I suspect you are mixing too many uncapped cells in with the capped ones. Too many uncapped cells makes the honey watery enough to allow mold growth, fermentation, and/or other types of spoilage. The rule of thumb is that a maximum of 10% uncapped cells be used, but it depends on how watery the uncapped cells are.

For a more accurate assessment, use a refractometer to measure the moisture content of your honey.

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