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Old May 15, 2012   #4
TomNJ
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Join Date: May 2009
Location: Floyd VA
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The key bad guy in home canning is botulism, but IMHO the fear of it is often over done. In spite of some 20+ million home canners in the USA, many of whom break the rules, botulism is very rare, especially for tomato products. In a ten year report on botulism incidents in America published by the Center for Disease Control (http://www.cdc.gov/ncidod/EID/vol10no9/03-0745.htm), we average only seven cases per year from home canning, and only one case from a tomato product in the entire ten year period (1990 to 2000). Additional reports show only four cases from tomato products in 18 years with no deaths, In addition, the survival rate for botulism is 96%.

I don't mean to underplay the dangers, just trying to put it into a reasonable perspective. I disagree with the common position that defines anything not proven safe as unsafe. There are degrees of safety, and many common things we do every day are a lot more "unsafe" than home canning. Every year hundreds of people die getting out of bed, slipping in the shower, falling down the stairs, choking on food, and getting into car accidents. Yet what do we do every morning - we get out of bed, take a shower, go down stairs, eat breakfast, and drive to work. How reckless can we get!

Botulism spores are everywhere, but only hatch and produce the toxin when conditions are right, i.e., low oxygen, low acidity, presence of water, and moderate temperatures. For safe canning you either need to kill the spores with high heat, or prevent them from hatching with high acidity, or both. High acids foods such as many fruits and pickled products require little processing, while low acid foods like corn, asparagus, and green beans, require severe processing, such as long cooks in a pressure canner.

Most tomatoes are high enough in acidity to prevent botulism (pH below 4.6), but the pH rises with the addition of too much low acid foods like onions, garlic, and peppers. Exactly how much of these sauce additions is acceptable is hard to say as even the "approved" recipes vary a lot. I use a fair amount in some of my recipes, but I also add citric acid to increase acidity and pressure can. If you keep the low acid additions low and add some acidity such as vinegar, lemon juice, or citric acid, you can safely can tomato sauce and salsa in a boiling water bath. Otherwise a pressure canner is best.

There is a lot of information on proper canning here: http://nchfp.uga.edu/how/can_home.html including approved recipes for tomato sauce and salsa.

Canning is a fun and rewarding hobby and I have been canning tomato products for over 35 years. Yes you should take care to follow recommended practices, but don't let the unrealistic fear of botulism that is often found on the Internet scare you away.

TomNJ
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