It is because the pressure canning times for tomatoes are equal the the boiling water bath times. There are no guidelines for canning them without added acid. It would take much longer than the times given without added acid. There is not a way to determine just how much longer it would take.
The USDA has found that most people do not want to pressure can the tomatoes as long as it would take without acid added. Even commercial tomatoes contain added acid if you will read the labels.
So, I have no guidelines as how to do so safely without adding it. Freeze the tomatoes instead.
The tomatoes would be processed so long without the acid that they would not even resemble canned tomatoes.
The soil they are grown in, the variety of the tomatoes, the density, etc. all affect the acidity of the tomatoes. Sorry, but there is no safe reliable way to know the acidity of the tomatoes you can at home.
To can them without the acid is risky, it gives you the risk of getting botulism.
I would not risk it.
This is from USDA. You will notice is says ALL steps, including acidification is required !! There is no safe way around it. I teach food preservation safety, so this is what the we know to be true.
:
If a procedure from the USDA Complete Guide to Home Canning for canning tomatoes offers both boiling water and pressure canning options, all steps in the preparation ("Procedure") are still required even if the pressure processing option is chosen. This includes acidification. The boiling water and pressure alternatives are equal processes with different time/temperature combinations calculated for these products.

Here is a link that might be useful: Univ. of Georgia on tomatoes.

I thought we had already covered this issue - in great depth - in your other post about adding acid to PC tomatoes. So what am I missing here?

Dave

Do I sense repetition here?

Why is lemon juice required for tomatoes, but not for tomato (spaghetti) sauce?

I would use it in BOTH. If canning a sauce with other items like onions, peppers, and herbs, the acidity level is even lower. Not sure where you saw that contradiction, but its not really safer for a sauce that has no added acid. Citric is the next best acid to add. Whole tomatoes canned ara a bit more dense too, and usually contain more water than a cooked down sauce, which cooks away water, but increases acidity slightly.

If the acid level is of concern, your friend could add a pinch or two of baking soda to the tomatoes when cooking them. It helps to lower the amount of acid in the toms.

Density between a sauce and the tomato pieces. Plus, I posted a long thing in another post about the reasons between types of veggies, etc.

I'll not only mention the baking soda to her, but will C&P, then print the pertinent replies and send them to her. Like myself she always canned them without extra acid and no one got sick. But she has no access to a computer to look stuff up online like I do.

I shudder to think of all that sauce my ex-husband would make and can for us that included mushrooms, garlic, onions, celery and other low-acid foods. He even canned basil pesto!

I'm curious.... is there a way to find out how many people become sick each year from home canned food? Not from tomatoes but from all home canned goods?

I doubt it because in many cases people become ill but have no way of knowing without testing whether it's attributable to home-canned food, commercially processed food or some other cause which may not be food-connected.

We do know that the great majority of botulism cases come from home-canned foods. Cases in the commercial sector now are extremely rare, though the FDA has warned processors not to become "complacent."

I've heard various figures from roughly 30-50 cases per year of food-related botulism. While that number is low in terms of total population, any case of botulism is of concern because it's fatal 30-65% of the time.

Carol

I'm looking at my pretty row of canned string beans here and wondering.... but I do gently boil all canned food before eating (not pickles of course). Isn't that some protection against botulism with the low acid home canned foods, including tomatoes? I don't know what my friend does with all her canned tomatoes, but do know mine are always well cooked after I open them because I'd rather make my sauce fresh each time, not make a big batch of sauce and can it. After opening my tomatoes I would get a gentle boil going, then add my tomato paste, browned onions and garlic, my mushrooms or peppers or already browned sausage and simmer it until it was as thick as I wanted it. I'm hoping the lemon juice doesn't ruin my sauces this year.

So let's tie this to the lengthy previous discussion on this from last week so it can be found in the future and so we won't have to repeat everything said there in this discussion.

Dave

Here is a link that might be useful: Adding acid to pressure canned tomatoes discussion

PS: greenhouser - She doesn't have to have access to a computer to keep up with the changes in the guidelines. The acidification rule has been in effect for many years.

All she needs is a new copy of the Ball Blue Book. All the current regs are covered in it.

Dave

I'm wondering why someone on a low acid diet is eating tomatoes.......

At least on any kind of regular basis?!?!?!?

Deanna

greenhouser... regarding your statement: "mine (canned tomatoes) are always well cooked after I open them".. I found this quote from LindaLou buried deep in the other thread:

"Oh, and the thing about boiling them first before you eat them. Well, if botulism is there, think about you opening that jar, touching the lid with botulism on it. Then, maybe dripping it on the counter. Just not really that wise to use boiling as insurance in my personal opinion. Either you processed them correctly and they are safe or they are not safe. So, I suggest do it correctly and no risk involved."

Also may I ask why you are looking at your green beans and wondering ... Did you PC them according to USDA recommendations?

Dave - I suggested she find herself a copy because like myself, she was out of canning for some time. Some of us who gave it up due to life changes or lack of time are now getting back into it in our retirement years. You may have easy access to canning supplies and books where you live but some of us don't see canning supplies or books where we live. Even the Walden Book Stores were I live didn't have a copy of Ball's Blue book. None of my local Wal*Mart stores had it. I ordered it online and haven't received it yet. People get back into canning and don't realize how things have changed in the past 10 or 20 years.

dgkritch - I don't know and didn't ask her. I'm not familiar with the disorder and what foods sufferers can and can't eat. She did mention giving up coffee, tea and soda.

Acidification of home-canned tomatoes was first required in the late 70's. In 1976 the first varieties of high-acid tomatoes were identified. So that recommendation has been in effect roughly 30 years.

As an example, Super Marzano has a pH of 5.20. The line for BWB canning is 4.6; obviously without acidification there's a problem.

Carol

You may have easy access to canning supplies and books where you live but some of us don't see canning supplies or books where we live. Even the Walden Book Stores were I live didn't have a copy of Ball's Blue book. None of my local Wal*Mart stores had it.

You have a Walden's Books! Now that I envy. I haven't been to a real book store in years. We are 37 miles from the nearest town with a population greater than 200 and it only has 11,000 but we still manage to find what we need when we go to town 2x a month.

The simple solution for your friend then is for you to print out the NCHFP Guidelines for her and mail them to her. That way she has alll the current regs at her finger tips. Although the BBB is easy to find in most any Ace Hardware, Farm & Fleet, Lowe's, Walmart or other general purpose store, they do sell out of them early in the canning season.

But I suspect, that just like you, she doesn't want to have to add the acid regardless of what the regs say. Change is hard for many. As Deanna said, if your friend is on a low acid diet then she has no business eating tomatoes anyway. But if she does then the very small amount of acid that is supposed to be added sure isn't going to make any difference in her diet.

Ultimately it is her choice and it's your choice. Your risk to take regardless of how many folks die from botulism. They are still dead. So no, none of us here is ever going to say that it is safe or approved to skip the acidification because it isn't.

Dave

Readinglady

I have 2 canning books. My canning books are from 1972 (Complete Guide to Home Canning by US Dept of Ag.)and from 1979 (Ball Blue Book) see page 23 where it claims even the low-acid tomatoes, unless overripe, were safe to WB. Neither one mentions acidifying tomatoes. You would think the BBB would mention it, yet doesn't. These, plus the Mirro booklet (bought canner in 1979 or 1980) were the only books my ex-husband and I went by for canning all those years. I suppose we didn't get sick because we always simmered the sauce we made back then. Any botulism was inactivated. I don't know, but some of those jars were canned with low-acid stuff along with tomatoes. He liked peppers, mushrooms and onions in the sauce. No one realized the danger. But he canned them and I honestly can't remember if he WB them or PC them. It was over 20 years ago. The toms I did were WB. I do plan to add lemon juice since I cannot find citric acid anywhere including in the Drug Stores.

Dave

We don't have Farm & Fleet here. The other stores you mention didn't have the BBB. I had to have ACE Hardware order me the Presto canner. I had to order the tomato squeezer and BBB online. I'm only 6 miles from a large modern town and about 14 from a good size rapidly growing city so have access to several of each store and all I found were the jars and at Wal*Mart, the seasoning. No one had Citric Acid or canning books.

She'll get the replies this coming week by snail-mail. I suggested she have her grandkids help her get online and look up canning information. It's up to her now.......

Sorry, I was off a bit. The pH problem was discovered in 1976, as I said, and the USDA and Extension agencies began working to resolve the problem, but formal publication of a USDA guide requiring acidification came in 1988. So it's only been 20 years. It's still a good long time.

However, even now one Extension agency provides instructions for processing tomatoes without additional acid, though it's limited to a few tomato varieties and with definite caveats.

Home canning is one of those areas very resistant to change. Acidification of tomatoes is only one of the issues of concern. A 2005 survey of home canners revealed that 30.5% "altered recommended canning procedures." 44% of respondents open-kettle canned at least some fruits and/or tomatoes.

Canning is a traditional art, and the majority of home canners get their information from family and friends. Those are not circumstances congenial to the adoption of new standards.

Carol

I was thinking about kayskats quote from lindalou about the possibility of "passively" contaminating a kitchen surface. So, while making my coffee this morning I took note of the different objects I used and their travels. Given that I'm pretty much a zombie before I have my coffee this was quite an effort for me. ;^)

If I had happened to contaminate the main counter (where my coffee maker is) I could potentially have spread it to a cupboard, the pantry, another counter and the kitchen table. I was amazed by this result. The trip to the pantry was because I had to refill my sugar bowl, so that's an uncommon event; all of the rest were pretty typical.

Makes ya think a bit.

... and that's not even considering the jar it came in. I do not think the water in the dishwasher gets hot enuf to kill bacteria .. maybe the soap washes it away?

Anyhow, this horse (PC acidification of tomatoes) gets whipped at least a couple of times a canning season (last year, I got in a few licks myself).

I have now come to the conclusion that there are three options:

1. Take a chance and leave out extra acid. The danger of botulism may be low, but only you can decide just what is your risk threshhold.
2. Follow USDA/NCHFP recommendations and add BOTTLED lemon or lime juice, vinegar or Citric Acid.
3. If, however, you cannot stand the taste of any of the above, pony up the big bucks and buy top-grade commercially canned tomatoes. That's what I do, but I must confess my decision is partially based on the fact that I do not grow my own tomatoes and I haven't been happy with the quality or price of what is available.

1. Take a chance and leave out extra acid. The danger of botulism may be low, but only you can decide just what is your risk threshhold.

It may not be so low if you don't bring the tomatoes to a boil and simmer them as some of us do. That may be why I never got botulism in the past when my ex-husband canned his special sauces with no added acids. If someone doesn't add the lemon juice or citric acid I hope they simmer the tomatoes for at least 15 minutes. That amount of time is supposed to do away with botulism but is most likely no guarantee.

Greenhouser, actually to rid a canned product of botulism it is not a simmer but a hard boil. By which point if botulism was present there is botulism spattered on you walls.

To find citric acid try going to the kosher section of your grocery store and buying sour salt. In my opinion you get a much better product when you use citric acid.

btw, the reason you did not die of botulism is probably that it was never present in the jars you had. It is like wearing a seat belt, if you never get in an accident it is totally safe not to wear one or to put your child in a car seat. I just don't like taking the risk that I will never get in an accident or that there will be botulism present when I can.

-Robin

We have Hispanic sections in just about all our stores but only one store has a very small Kosher section (very few Jewish people here). I can look there. Thanks. It never occurred to me to look where they sold Kosher foods.