https://extension.colostate.edu/topic-areas/nutrition-food-safety-health/canning-tomatoes-and-tomato-products-9-341/

For pints, add 1 tablespoon bottled lemon juice or 1/4 teaspoon citric acid. Freezing is a safe, easy alternative to home canning. Frozen tomatoes and tomato ...

https://foodsafety.wisc.edu/assets/preservation/UWEX_addacidtomatoes.pdf

new recommendation to add acid to all home-canned tomato products. ... tablespoons of bottled lemon juice or ½ teaspoon of citric acid per quart of tomatoes.

https://www.freshpreserving.com/ball-citric-acid-for-preserving-tomatoes-7.5-oz.-1034059VM.html

This product provides a pantry-ready alternative to lemon juice when canning tomatoes. Citric acid lowers the pH without changing the tomato flavor like lemon  ...

https://www.healthycanning.com/citric-acid-and-home-canning/

Pure crystalline citric acid, USP (meaning 'United States Pharmacopoeia' and therefore of uniform stability and quality), is the acid added in canning tomatoes ...

http://www.homepreservingbible.com/1081-canning-tomatoes-citric-acid-vinegar-lemon/

When canning tomatoes safely at home, be sure to use tested canning recipes that add citric acid, vinegar or lemon juice. Tomatoes are a medium-acid food with ...

https://nchfp.uga.edu/how/can_03/tomato_intro.html

Green tomatoes are more acidic than ripened fruit and can be canned safely with ... For pints, use one tablespoon bottled lemon juice or 1/4 teaspoon citric acid.

https://nchfp.uga.edu/tips/summer/canned_tomato_types.html

Home canned tomatoes may prepared in a ready-to-use crushed format or left whole ... of bottled lemon juice or ½ teaspoon of citric acid per quart of tomatoes.

https://www.canr.msu.edu/news/acidifying_your_home_canned_tomatoes

Sep 5, 2014 ... It is critical when home canning tomatoes, whether they are whole, crushed or ... Adding the recommended amount of lemon juice (or citric acid) ...

https://www.simplycanning.com/how-to-can-tomatoes.html

Green tomatoes are more acidic than ripened fruit and can be canned safely with ... For pints, use one tablespoon bottled lemon juice or 1/4 teaspoon citric acid.

https://foodinjars.com/blog/canning-101-how-to-swap-citric-acid-for-lemon-juice-and-vice-versa/

Oct 25, 2018 ... This is why tomato recipes typically call for the addition of either bottled lemon juice or citric acid. Both products deliver a reliable dose of acid ...