Hi Melissa, 

This is an interesting recipe from a food safety standpoint! 

On the one had, you've got typical ingredients in a fresh salsa: uncooked tomatoes, onions, peppers, etc. Usually, these sorts of fresh salsas only keep in the refrigerator for 5-7 days before they start to spoil or develop off flavors. Because they're not cooked, any bacteria that's on the initial produce can start to multiply even in the refrigerator. This is particularly a problem with listeria, a bacteria that can grow at cold temperatures and has been found in salsas. We don't recommend storing fresh salsas longer than a week for safety.

On the other hand, your recipe calls for ingredients that increase the acidity or reduce the available moisture, both of which make it hard for bacteria to grow. Vinegar, sugar, and salt all do these things, and ketchup does too (it has even more vinegar, salt, and sugar!). If you cut back on the ketchup in this recipe, you are cutting back on one of the ingredients that slows down spoilage.

Even with these preserving ingredients added, however, I would not recommend storing the salsa anywhere near as long as the recipe claims it can be stored. Without any cooking step to help kill bacteria, you run the risk of having pathogens on the raw ingredients multiply during storage. If you did have some pathogens (like listeria) in the initial mixture, there might not be enough vinegar in this recipe to prevent it from growing over time. Because the recipe hasn't been tested to show what the final acidity (pH) is, it's impossible to say how long it can be safely stored. For safety's sake, I would either freeze this product for long term storage, or eat within a few weeks of storing the refrigerator.

Thanks for using Ask Extension!

Jared