Lemon is more acidic than vinegar. If you replace the vinegar with lemon, it should be fine. If the pH is too high and you’re breeding botulism spores, there would be no obvious signs of the problem. If the pH is low enough to prevent botulism (4.6 or lower), spoilage would be likely be indicated by mold growth, bulging lids or other obvious signs of spoilage. If reprocessing is needed, it should be done within 24 hours.
I’ve read so many forums on this dang salsa recipe (it originated on the gardenweb forum) and to be honest, I’m not sure. There are a lot of people that say don’t deviate from the recipe for food safety and others say the tomato paste and tomato sauce can be optional because mostly you just want a mixture that sloshes around freely (if it’s too thick, apparently it can’t be heated through well enough to prevent bacteria from growing). My gut feeling says you are ok…but you’ll just want to use your best judgment.
I fell in love with Mexican food during a 2003 trip to California. Head over heels in love. I’m not talking your Chipotle Mexican Grill nonsense or your Taco Bell Tex Mex disgrace, I’m talking the sight and sounds of your host family’s Latin American sister-in-law chopping up wine-ripened tomatoes and fresh Jalapeños for Pico de Gallo on Thanksgiving. I’m talking pounding Coronas with Rudy all day and talking cultural differences, dreams and life in general. I’m talking the sound of Mariachi bands playing tableside in a side alley eatery near LA’s historic Olvera Street. The banging of pots from the stuffed taqueria kitchen. The smell of the spices hitting the heat of the stove… I love Mexican food. The authentic kind of Mexican food that few of us get to experience and shockingly many of us never knew existed… THIS, the authentic and the real, I love it!