What Can I Do About E. Coli In My Apple Cider?

How Escherichia coli Move
How Escherichia coli Move (Photo credit: Microbe World)

I came across an article about concerns of E. Coli contamination in apple cider.  For those who aren’t familiar with E. coli O157:H7, infection “often causes severe, acute hemorrhagic diarrhea.”

I looked into these concerns, and found a lawsuit against a grower in Food Safety.  The article didn’t make me feel safer, noting that animal fecal material may get on ground harvested apples, and may not come off when washed.

In a public health discussion, the best way to avoid e. coli in unpasteurized apple cider is to pasteurize apple cider.  But that would be the end of the apple cider industry except for big manufacturers who can afford the pasteurization process.

So there has to be another way.

Enter in the herbs and spices.  “Cinnamon oil and clove oil strongly inhibited the growth of E. coli O157:H7 at neutral and acidic pH.” (abstract below)  The addition of cinnamon and clove oil at one part per 10,000 combined with mild heat was sufficient to kill off e. coli.

To put it in laywoman’s terms, mull yer cider.  The mulling process not only makes cider taste good, it protects your guests from taking a little critter home with them.  In case you’ve never heard of mulling your cider, here’s a simple recipe.

Let me finish by saying that a very small outbreak on the west coast shouldn’t stop anyone from purchasing and enjoying their cider.  Almost all your cider is fine to drink, but if you are concerned, just mull it.

Here’s the abstract:

J Food Prot. 2007 Sep;70(9):2089-94.

Influence of cinnamon and clove essential oils on the D- and z-values of Escherichia coli O157:H7 in apple cider.

Knight KP, McKellar RC.


Food Research Program, Agriculture and Agri-Food Canada, Guelph, Ontario, Canada N1G 5C9. knightk@agr.gc.ca


Escherichia coli O157:H7 has become a concern within the apple cider industry. The purpose of this study was to screen several essential oils and isolated components for antimicrobial activity against E. coli O157:H7 in tryptic soy broth at neutral and acidic pH and to assess the effect of these additives on the D-value of E. coli O157:H7 in apple cider in combination with mild heat treatments. Cinnamon oil and clove oil strongly inhibited the growth of E. coli O157:H7 at neutral and acidic pH, (R)-(-)-carvone and (S)-(-)-perillaldehyde were moderately inhibitory at both pH 7.2 and pH 4.5, and citral and geraniol displayed moderate activity at pH 4.5 only. Lemon oil, methyl jasmonate, and p-anisaldehyde displayed little or no antibacterial activity. A synergistic effect between the essential oils and the lower pH of the growth medium was evident by consistently lower MICs at pH 4.5. Cinnamon and clove oils (0.01%, vol/vol) were further tested in apple cider in combination with mild heat treatments for the practical control of E. coli O157:H7 in apple cider. The addition of either essential oil resulted in lower D-values than those for cider alone, suggesting a synergistic effect and the potential efficacy of a mild heat treatment for apple cider.

PMID: 17900087


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