Homemade Indian style pickles and botulism

[Jenni]

I love making pickle. This year I made a new pickle, indian-style garlic pickle with oil, spices and salt. We opened it last night and tried a bit. My Dad happened to mention that he had heard that garlic preserved in oil and kept at room temperature for a long time can be at risk of containing botulism. A quick google reveals that this is indeed a risk, and we have decided that for safety, we will dispose of the rest of the pickle and not eat any more.

However, it got me thinking about the other pickles I make. I make indian style pickles in a traditional manner, so I add no vinegar. Unlike western pickles with vinegar, they do not always contain added acid, though some do have lemon juice and they are also supposed (I think) to create acid through lactic acid fermentation. It occurred to me that I am probably rather lax about my preservation methods, and my pickles do tend to sit at room temperature for a very long time. I believe the worry with garlic in oil is that garlic is a low acid vegetable and the oil creates an anerobic environment which is perfect for botulism toxins to proliferate. When it sits at room temperature for a long time, this creates certain conditions which increase the risk. So the obvious suggestion might be to not make garlic pickle at home, but what are the risks for other pickled items involving oil and no vinegar? My squash pickle also contains a low acid vegetable, lots of oil, spices and salt - is it dangerous? I haven't died yet, but I don't want to take stupid risks or endanger my family.

Here is how I usually pickle: I take fruit or vegetables such as green mangoes, chillies, limes, carrots, cauliflower, etc. These are usually cut up in some way, and sometimes I parboiled them (in the case of veg such as cauliflower, carrots, etc.) and other times they are left raw. They are then mixed with spices and salt.

The next step varies on the kind of pickle I am making. Broadly speaking, I make three kinds. The first kind involves parboiling veg, drying them well, adding spices and salt and pickling them in the cooled liquid in which they were originally parboiled. The second kind is a lemon or lime pickle with no oil - the fruits are mixed with spices and citrus juice. The final kind involves oil. I usually use mustard oil for north indian pickles, and sesame oil for south indian. The oil is heated and allowed to cool a little, and then poured over the veg-salt-spice mixture. Most recipes tell you to cool the oil completely but I often add it whilst it is still warm. The pickles are put into kilner jars that have been washed and heated up in an oven. The pickles are supposed to be kept in a sunny place for several days or weeks and then moved to a cool storage place for a while longer to mature before use. In practice, as it is not always that sunny where I live, I tend to leave the pickling jars in my conservatory for weeks or months till the pickle is ready - this is evident when the fruit or vegetable being pickled has softened and the pickle has a pickle-y taste.

I don't want to panic unnecessarily, but I do want to be able to make pickles confidentally without worrying about suddenly getting botulism. My Dad's philosophy is that people have been making pickles this way for centuries, so I shouldn't worry. My philosophy is that people used to die of a lot of things that we now consider preventable and/or treatable, so I don't want to take stupid risks.

Unfortunately I a lot of the stuff on the internet about botulism is about home canning or making western style pickles with vinegar in them. This doesn't apply to the kinds of pickles I make, so I'm finding it hard to get information. So, any advice (preferably not just anecdotal - I need some hard science guys!) would be much appreciated.

[percival]

Clostridium botulinum on Wikipedia has useful info. To prevent the release of the deadly neurotoxin, you need an environment with either:

- almost no water,

- high oxygen,

- high acidity,

- high concentrationof dissolved sugar, and/or

- temperatures below 38 Fahrenheit.

To destroy the actual botulin toxin, you only need to heat your food past 140 degrees. However, the spores will continue to live and will grow and release more toxin in low acid environments like an infant's digestive system. To actually kill the spore, you need to cook your food to 250 degrees. This is why pressure canning, which cooks at ~250, is the only safe method prescribed by the USDA for the canning of low acid foods.

If you're not using high acid with wet vegetables, the only safe way is by cooking and pressure canning at 250. Otherwise you need to treat them as unsafe and consume quickly/without long term storage.

[Jenni]

Just out of interest, how do your above suggestions apply to things like kimchi and saeurkraut? Does the acid produced in lactic acid fermentation prevent botulism?

[loki]

Saurkraut and kimchi are safe because the lactic acid fermentation makes them very acidic. They also have a high level of salt (though this is probably more of filter through which the lactic acid bacteria survive and thrive then do their work making acid rather than preventing botulinum growth - as this requires very high salt content). In the US, the Extension Services (outreach services of our State Universities) often have recommendations about sauerkraut and fermented pickles and maintain that it is quite safe.

I make Indian pickles too, and don't really worry too much. The one thing you have going is that these pickles are exposed to oxygen quite a lot. But even a little oil can make an oxygen poor environment. Another thing Indian pickles have going for them is high salt content (so don't change the recipe to make low-salt versions!). For the garlic pickles I would really wash the garlic cloves, and then put the garlic through a bath in boiling vinegar. Then keep the pickles refrigerated. However use your own judgment here and don't rely on me! I made a squash pickle and it started to mold, so threw it out. But I'm going to make it again. I acidified it though.

Here's another recipe for garlic pickle - with limes. Sounds pretty good. The site seems to be very aware of botulism...

garlic pickle Acids in Indian Pickles

Now I would not worry excessively about it. Cold will prevent botulinum growth too - especially from those strains commonly found with vegetables. There are some strains that still are active in cold, but they grow very slowly so consuming these pickles more quickly will help.

One thing about this subject is that I can't find references or cases of botulism sourced from Indian pickles. If you can find any you might get insight from these too. Maybe this is a good sign. Partly it may be that these pickles are so strongly flavored you rarely eat more than a tablespoon at a time...

Lastly - The exposure of many of these pickles to UV light and use of other spices (especially mustard and foenegreek) is supposed to either kill or suppress micro-organisms. However without real proof of this, I can't say that it works. There was a myth about chile peppers in New Mexico that stated they were protected because of their heat. But that is completely false and many have succumbed to food poisoning from poorly kept chiles (mostly roasted green chiles that have been left at too high a temperature for too long).

[MaxH]

Jenni, relevant basics of botulinum safety have been examined repeatedly here on eG, even recently e.g. Here, and it is worth your time to review the existing discussions -- specifically for links to external authoritative sources (UN WHO, US CDC or USDA, national Health Ministries, &c.) such as WHO Fact Sheet 270.

I apologize for repetition but you DO NOT want to ask random people online about this subject. Unfortunately that usually produces responses, always heartfelt, often wrong; yet it's not a subject where misinformation is OK. (Maybe not as bad as asking in late December about hangover cures -- guaranteed to evoke armchair advice sometimes merely useless but sometimes potentially lethal.)

As you should confirm from authoritative sources, a standard reference point is pH of 4.6 or more acid. That's only slightly acid to the palate. In the US it's often achieved commercially in inadequately acid foods (like fresh basil-garlic-nut "pesto" sauce) by adding food-type acids to lower the pH below 4.6, and the result doesn't taste particularly sour.

[scott123]

I apologize for repetition but you DO NOT want to ask random people online about this subject. Unfortunately that usually produces responses, always heartfelt, often wrong; yet it's not a subject where misinformation is OK. (Maybe not as bad as asking in late December about hangover cures -- guaranteed to evoke armchair advice sometimes merely useless but sometimes potentially lethal.)

Since there are no authoritative sources on Kimchi and other lactic acid fermented foods such as Indian pickles, anecdotal information is a lot better than none.

This isn't like a restaurateur requesting information about the bacteria danger zone in an online forum. The government publishes scores of data relating to the danger zone. This is a subject without any governmental guidelines whatsoever.

Ask any Korean about the safety of Kimchi and they'd laugh in your face. There also seems to be a very long safety record for Indian pickles. Garlic pickles might be a concern, depending on how they're made, but telling people only to refer to government literature and not ask other chefs about it is incredibly shortsighted in my opinion.

Does the acid produced in lactic acid fermentation prevent botulism?

Yes, it does. This page here does an excellent job of summing up the safety of Kimchi:

http://www.eatingoffthefoodgrid.com/a/hm_kimchi.htm

Lactobacillus grows naturally on cabbage leaves, making cabbage especially suitable for error proof fermentation. Garlic, though, is a different story- garlic minus air plus room temp- hello botulism.

Could you post your recipe?

Edited October 9, 2010 by scott123 (log)

[Jenni]

Thanks for the input guys. It's funny because I've been making pickles for quite a few years now, and other members of my family have made various preserves on and off over the years. It's only now that I have thought about it a bit that I realise I should probably be a bit more careful. The most common pickles I make are mango (the green kind, unripe and sour) and lemon/ lime. I am assuming these are probably acidic enough to be ok. I think from now on I will probably start adding an acid to less acidic veggies such as carrots and so on.

Loki, I did come across that indiacurry.com site a little after I posted my original query. I thought it was an excellent site and I will probably use its trick of acidifying low-acid produce before pickling from now on. I'm leaning on lime or lemon juice, as I don't really like to use vinegar in Indian pickles.

I just want to add that from what I have read, botulism thrives in an anaerobic atmosphere, aka in an oxygen-free atmosphere. This is why, according to indiacurry.com, it is important to acidify low-acid produce BEFORE adding oil (as the oil coats the produce and forms a sort of layer). Therefore, if you make a pickle of some vegetable such as garlic, without acid, and leave it for a long time at room temperature (as you may do whilst waiting for it to mature) then you can put yourself at risk. Apparently refridgeration is not always a reliable way of preventing botulism growth, and commercially produced garlic-in-oil products have to go through certain steps during the production process in order to be considered fit for sale. I have also heard (again, anecdotal) that salt in oily preserves/ pickles does not always help - something to do with it not dissolving well in the oil. It may be complete nonsense, but there it is.

The trouble is with stuff like this is that this kind of pickling has been going on for yonks. And plenty of people "have been doing it for ages and haven't had a problem". Thing is, it only takes one mistake for someone to add pretty nastily ill, or worse. So, as I said, I don't want to panic, but I do want to get some facts straight.

Btw, we did consult the NHS direct helpline (we, that is to say my Dad and I, did eat quite a bit of the garlic pickle last night and this morning! :0 ) and they said that this kind of garlic preserve can be quite risky, and said that if we get any of the symptoms of botulism we should call 999 and explain that we have eaten a high risk product and so on. Personally, I am inclined to think we might be ok, but I wanted to check and that's why we rang.

Scott123, with regards to the garlic pickle recipe - I remember that I adapted the recipe from a Madhur Jaffrey recipe. There's no acidic substance in the original recipe, and in my scrawled notes I can see that I didn't add anything acidic along with any of my other ingredient additions. I also deviated from the maturing instructions that she gave (something like 10 days out maturing, and then put in the fridge) and left it maturing for a good few months. I have to say, it smells great. Has a strong flavour and is rather salty too. I am slightly sad to see it go, but I don't feel at ease enough to keep eating it!

[MaxH]

... This is a subject without any governmental guidelines whatsoever. ... Garlic pickles might be a concern, depending on how they're made, but telling people only to refer to government literature and not ask other chefs about it is incredibly shortsighted in my opinion.

Sorry if I was unclear earlier. (That response above appears to mis-read my intended meanings.)

(1) I referred to people requesting general information about botulism safety and what measures reliably prevent it. The thread was already rehashing that subject. That topic does have both extensive publicly available government information, and extensive dangerous armchair misinformation. Some of the latter can be found on eGullet in past threads related to botulism safety.

(2) This was not about "asking chefs" but about asking online public fora. Many people who read eG and answer queries like this are not food professionals.

If the answer is simply that adequately acid food is adequate to prevent botulism (the very reason US cookbooks traditionally limited their home-canning canning recipes to certain fruits), I am not a food scientist and I would not presume to advise people how to guarantee that. But as a point of general information, you can get a supply of standard pH-sensing paper strips for a few dollars at any lab-supply firm (that's where I've gotten them, they come in little plastic boxes the size of matchbooks). Electronic pH meters also are available, but are generally much more expensive. These standard methods easily tell you quantitatively how acid the food is -- more accurately than any rules of thumb.

[helenjp]

Obviously, anybody who is not a food scientist specializing in C. botulinum should read and speak with caution, but I feel we can still gain something from tabling the topic.

Japanese sources point out the different geographical distribution of different types of C. botulinum, and how this has affected traditional food safety practices. Apparently type A is particularly likely to be found in the US, type B in middle-latitudes and southern Europe, and type E in countries that love their preserved fish, such as Japan and northern Europe. Type A and Type E in particular thrive at different temperatures and will tolerate different levels of acidity. Generally, Type A is more virulent and more resistant to heat. Conversely, refrigeration may not be enough to knock Type E on the head.

Another point worth considering is that we may only be killing the toxin already produced, not the spores that produced it - hence the need for proper storage and prompt consumption of the prepared food.

So, food pickled one way "back in The Old Country" may not be safe pickled the same way in another country, where there is a higher risk of contamination from an A or B type of C. botulinum. I don't know which types of botulinum were traditionally most prevalent in India, but I'm guessing that major cities anywhere in the world nowadays can offer us a choice of all three of the most popular types!

This link is a bit information-dense, but it is one of the few places I could find in English that mentioned the differences between different C. botulinum types.

FDA on precautions for different C. botulinum types

Edited October 10, 2010 by helenjp (log)

[dougal]

... There's no acidic substance in the original recipe, and in my scrawled notes I can see that I didn't add anything acidic along with any of my other ingredient additions. I also deviated from the maturing instructions that she gave (something like 10 days out maturing, and then put in the fridge) and left it maturing for a good few months. I have to say, it smells great. Has a strong flavour and is rather salty too. I am slightly sad to see it go, but I don't feel at ease enough to keep eating it!

Jenni - as correctly stated above, things don't need to be VERY acid to control Botulism risk. The pH of 4.6 is about 100x less acid than the market-leading Cola drink ...

You can measure pH (acidity) with simple cheap paper pH test strips. These are kinda like Litmus paper, but the particular colour gives you a measurement. There's a discussion of them (and the difficulties of using them on dryish stuff) in a thread on here about salami-making -- another place where Botulism risk needs to be considered.

If this is of sufficient concern to you, invest (probably £10 or less) in some pH papers (covering a small range either side of 4.5) and test your produce. Anything 4.0 or less and you don't have to worry at all about Botulism.

Fermenting is a common way that traditional processes achieve safely acid conditions. Likely the Mrs Jaffrey recipe was trying to take it far enough, and then (near enough) stop the fermentation by chilling.

The point here is that you'd be wanting to test a sample of each pickle batch AFTER fermentation ...

The thing about oil is that it smothers (excludes air from) whatever is submerged in it. And excluding air is just what C. Bot really likes.

The thing about garlic is that its a root - from under the soil. And soil (earth) is where you can easily find C Bot.

Get a speck of earth under your oil, and you have plenty scope for growing C Bot.

Kept under refrigeration, 'clean' peeled garlic in oil should be fine for at least a fortnight. And if you reduce the C Bot further (as with blanching in hot vinegar), the risk will be reduced for longer.

Edited October 10, 2010 by dougal (log)

[Jenni]

Thank you everyone for your interesting and insightful answers. I think I'm getting to get hold of some litmus paper-type thing as suggested and test the various pickles I make. The lemon/lime and mango I confidentally predict will be fine, and I'll be able to see how well the other varieties do. Sadly we've recently finished the squash pickle and the chilli pickle, and we only have mango and lime left, so it looks like I'll have to go on a pickle making spree to really test this out!

One question, when should you do the pH test? If you test at the end of the maturing period, you will indeed find out the pH of the end product. However, isn't the important thing that there is an inhospital environment for the botulism spores at the beginning of the maturing time, and therefore isn't it the pH of the pickle before maturing that counts? Something that ends up with a reasonable pH by the end might be pretty low acid at the start, and surely in the time it takes to become acidic, a whole lot of botulism toxin could have been produced? Or will the acid environment not only prevent botulism spores from proliferating but also kill of any toxin produced if the product has only become acidic after a while? Apologies if this is not clear...

Edited October 10, 2010 by Jenni (log)

[djyee100]

Or will the acid environment not only prevent botulism spores from proliferating but also kill of any toxin produced if the product has only become acidic after a while? Apologies if this is not clear...

You have to make the distinction between the spores of the bacteria and the toxin they produce when they grow.

This is the rule of thumb I learned when I was taught how to can:

Botulism requires an anaerobic environment, most commonly achieved by the vacuum seal in canning. However, certain environments will prevent and inhibit the growth of the spores (& the resulting toxin), namely environments with sufficient levels of

--alcohol

--acid

--salt

--sugar

If the spores do grow, they produce a toxin that can be destroyed by boiling. However, with most preserves, people don't boil them--they eat them straight from the jar.

The spores exist in the ground and show up naturally on foods. You cannot rely on destroying them by normal boiling temperatures. Instead, to destroy the spores, it's necessary to use a pressure canner with extra-high temperatures.

In short you have 2 choices to prevent botulism, assuming the basic requirement of an anaerobic environment is present: (1) create an inhospitable environment for growth of the spores (& resulting toxin) with sufficient alcohol, acid, sugar, and/or salt ; or (2) destroy the spores from the get-go with a pressure canner.

From Harold McGee's On Food and Cooking:

"...the bacterium Clostridium botulinum...being anaerobic, thrives in the airless cans and produces its deadly nerve toxin, which causes botulism. The toxin itself is easily destroyed by mere boiling, but the bacterial spores are very hardy...Unless they are killed by the extreme condition of higher-than-boiling temperatures, the spores will proliferate into active bacteria once the can is cooled down, and the toxin will accumulate."

When I've cooked oil pickles, I've made small batches, didn't bother to seal them, and kept them in the fridge. So my practical experience can't help with your particular question.

[MaxH]

Again this topic is rehashing general botulism info treated thoroughly in earlier eG threads on the subject.

Here's something different: background on quantitative food acidity and its intuition. Please check standard sources if you're interested; don't rely on me for critical details.

pH is an attribute of water solutions, their acidity or alkalinity. Like Richter earthquake energy scale, pH is logarithmic: one degree lower pH means essentially 10 times higher concentration of hydrogen (i.e., positive, i.e. acid) ions. A pH of 7 is neutral (pure water); below 7 the hydrogen ions dominate, and the liquid is called acidic.

Around pH 5 and below, foods taste acid. ("Sour" = human language for the specialized pH detector within our sense of taste.) I first measured some food pH's around 1970 and found lemon juice had a pH of 2. That's exactly 1000 times higher acid concentration than a pH of 5. If you diluted pH-2 lemon juice with pure water to 10 times its volume, you'd change the pH from 2 to 3. (You now know how to easily estimate lemonade pH.)

C. botulinum spores (randomly common in nature, notably on surfaces of plants and seafood) develop to active bacteria only in anaerobic environments of pH 4.6 or higher, according to official data. Less widely explained is that contrary to some claims, complete oxygen exclusion is unnecessary for this growth [Merck Manual, 2006 professional ed.].

Quantitatively, pH 4.6 is like 400:1 dilution by pure water of a hypothetical pH-2 lemon juice (10 to the power 2.6 is about 400.) That gives a sense of how acid a 4.6 pH is. Juice of many fruits has natural pH well below 4.6, hence botulism growth is seldom an issue when home-canning them.

Unless pressure-sterilized to 120 °C (250 °F) -- note you cannot achieve this in aqueous foods at normal air pressure regardless of temperature of your oven, boiling fat, etc., a persistent point of misconception -- the C. bot. spores remain viable. That means they could grow if their liquid environment's pH ever goes above 4.6 while sealed from air. Though I haven't researched this, I conjecture that the slow decomposition occurring over years (caramelization and so on) might occasionally raise the pH into the danger zone even if food was canned with safe initial acidity. It might explain anecdotes I've heard about home-canned fruits, neglected for decades, developing anaerobic bacteria that generates gas and bursts their glass jars.

[haresfur]

Again this topic is rehashing general botulism info treated thoroughly in earlier eG threads on the subject.

Here's something different: background on quantitative food acidity and its intuition. Please check standard sources if you're interested; don't rely on me for critical details.

pH is an attribute of water solutions, their acidity or alkalinity. Like Richter earthquake energy scale, pH is logarithmic: one degree lower pH means essentially 10 times higher concentration of hydrogen (i.e., positive, i.e. acid) ions. A pH of 7 is neutral (pure water); below 7 the hydrogen ions dominate, and the liquid is called acidic.

Around pH 5 and below, foods taste acid. ("Sour" = human language for the specialized pH detector within our sense of taste.) I first measured some food pH's around 1970 and found lemon juice had a pH of 2. That's exactly 1000 times higher acid concentration than a pH of 5. If you diluted pH-2 lemon juice with pure water to 10 times its volume, you'd change the pH from 2 to 3. (You now know how to easily estimate lemonade pH.)

Disclaimer, I'm not a food scientist, I'm a geochemist, but I'd like to add something to the above.

pH is effectively a measure of free acidity or free hydrogen ion. So in an ideal situation the dilutions work as above, however there can be other factors that buffer the pH so it doesn't change the same amount as you would expect by adding an amount of acid or by dilution. The reason this is relevant to the discussion is that you shouldn't assume that, say, adding 1 ml of lemon juice to 99 ml of your food product, for a 100 time dilution, that you will end up with a pH of 4. You can end up with a higher pH because the buffering reactions keep the acid from dropping the pH that far, and for that matter, the amount that you would use for one recipe isn't necessarily the same as you need for another. There are other nuances, but the underlying point it to be aware that it isn't completely straight-forward.

[Jenni]

Sorry for making people repeat points, but thank you for the clarification re spores and toxins.

From what I understand then, since pickles are not cooked before serving, it is necessary to add an acid at the start of the maturing process to prevent the spores from proliferating (and thus producing toxins). Any acid added or formed near the end of the process would not destroy any toxin that had already been produced.

[djyee100]

From what I understand then, since pickles are not cooked before serving, it is necessary to add an acid at the start of the maturing process to prevent the spores from proliferating (and thus producing toxins). Any acid added or formed near the end of the process would not destroy any toxin that had already been produced.

That is correct.

Are you including lactic acid fermentation in your question? Because that anaerobic fermentation is another game entirely, as I learned on this EGullet thread:

ETA: Edited out part of the response because I misread Jenni's last post.

BTW, I'm not convinced that oil pickles create an anaerobic environment that's conducive to botulism. I'm not saying yea or nay. I'm saying that from the evidence available, I'm not convinced there's a problem here.

Edited October 11, 2010 by djyee100 (log)

[MaxH]

you shouldn't assume that, say, adding 1 ml of lemon juice to 99 ml of your food product, for a 100 time dilution, that you will end up with a pH of 4. You can end up with a higher pH because the buffering reactions keep the acid from dropping the pH that far, and for that matter, the amount that you would use for one recipe isn't necessarily the same as you need for another.

A superb point haresfur, and thanks for posting it. I was writing only about how pH tastes, in simple situations. (Water and lemon juice to pH 4.6 is one lemon's 50 ml of juice added to 20 liters or five gallons of water -- easy to visuallize. I think you'd taste it, but not strongly acid.)

But to adjust food pH deliberately, you must test pH of the result -- a "closed-loop" process rather than "open-loop," at least until you have experience with the specific recipe.

Just as good cooks taste along the way, and "cook until done," rather than blindly following some fixed recipe formula with no account for ingredient and equipment variatons. Except that errors there disappoint, rather than kill.

Jenni, you're exactly right, C. b. toxins are reliably vulnerable to heat, not ingredients. That's part of the sharp distinction between spores, bacteria, toxin -- all very distinct as to nature and prevention. Frequent confusion between the properties of the three (even by food writers) is why it's vital to read up directly from the easily available public health sources.

[djyee100]

From what I understand then, since pickles are not cooked before serving, it is necessary to add an acid at the start of the maturing process to prevent the spores from proliferating (and thus producing toxins). Any acid added or formed near the end of the process would not destroy any toxin that had already been produced.

That is correct.

I meant to say, before the EGullet computer threw me out of Editing mode so I couldn't finish my changes:

That is correct. That is the principle of canning, where the vacuum seal clearly creates an anaerobic environment at risk for botulism. It's not clear to me what process is going on with your Indian oil pickles, whether oil pickles present an anaerobic environment at risk for botulism, and how canning principles apply here, if at all. Just saying this to put things in perspective.

[Dianabanana]

You're going to find that the trouble with litmus strips is that the color of your food will obscure the color of the paper. What you can do instead is to call over to the food science department of your local university and ask if they'd be willing to test a sample with their pH meter. I've done this and they were happy to do it and at no charge. I'm sure lots of other places are equipped with pH meters as well, if you don't have a university near you.

[MaxH]

You're going to find that the trouble with litmus strips is that the color of your food will obscure the color of the paper.

Good point (it's a famous problem in applications like wine).

A quick call to my reliable silicon-valley scientific equipment dealer, Lab-Pro Inc. (link below FYI), disclosed what was news to me: compact electronic pH meters are now available circa USD $80 designed for this kind of range, for food and wine applications. (They were much more expensive when I used them as a student.) So you may want to consider this if you do much, or professional, cooking. (Maybe it will go fashionable, like sous-vide quipment. Historical note: If you review the long sous-vide thread here, you'll find that some years ago, Lab-Pro was the first to specifically propose adding inexpensive servo temperature-control technology to electric cookers to obtain a sous-vide cooker around $100 instead of then-standard lab water baths circa $1000. Home-built and then commercial versions followed.)

Lab-Pro said they sell versions from Hanna Instruments (good firm FYI) and Extech (I think Extech pioneered the pocket-sized non-contact IR thermometers a few years back, I have one) and that there are certain quirks, requiring acclimation by new users. The heart of the meter is the probe tip which is expendable and lasts around a year of use; costs circa $40-50 to replace (the gentlemen dubbed these the "razor blades"). The tips should be stored in a solution. The meters require re-calibration periodically, for which another expendable (a pH reference capsule) costs a dollar or two.

I think I'm going to get one of these, and if so will report.

http://www.lab-proinc.com/

[vice]

Max,

Have you by chance picked up one of the inexpensive Lap-Pro meters? It would make a great gift for someone who makes fermented foodstuffs at home (i.e. me).

[MaxH]

Have you by chance picked up one of the inexpensive Lap-Pro meters?

No, I haven't swung by the distributor (Sunnyvale's Lab-Pro) yet to look at them. Coincidentally, a winemaker friend swears by a Hanna Instruments handheld unit (description closely fits what I got from lab-Pro above) and uses it heavily, mainly in the pH 3-5 range, for wine, periodically checking it both with calibration specimens and with separate tests on the wine. He said he needs a new sensor head after using the current one for a few years (per above).

I believe that this 3-5 pH range in winemaking is exactly the range needed to verify that food is acid enough to reliably prevent anaerobic spore germination.

[djyee100]

Rosetta Costantino's new cookbook, My Calabria, has a note about oil-preserved foods that might be useful. Costantino has kept oil pickles in a cool pantry, but recommends refrigeration for added safety. The "Note About Calabrian Sott'Oli (Foods Preserved Under Oil)" is available on Googlebooks, Page 280 (scroll up):

http://books.google.com/books?id=86R77RdzTj8C&pg=PA281&lpg=PA281&dq=my+calabria+costantino+oil+pickle&source=bl&ots=vW5gLJIsd7&sig=wTINchIv7D_iECKtvjVx6CfvQqA&hl=en&ei=Tn4KTY2EAYacsQO48cDFCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBMQ6AEwAA#v=onepage&q&f=false

[Lisa Shock]

I'd like to point out that refrigeration doesn't help the situation. Some strains thrive at 38°F - 113°F, the lower end of that range is where most of us keep our fridges. Temperature is a vital part of the equation here, along with time. The above post from a few months back allowing storage under refrigeration for a fortnight could be recipe for tragedy. Here's a botulism factsheet from Colorado Sate University.