citric acid usage for packaged hummus We are trying to come up with a hummus product which will have a shelf life of at least one month. We will cook the chickpeas first then add all the other ingredients and blend. Product will be packaged in jars. Do you know how much citric acid should I use to extend the shelf life? And should it be in powder or liquid? 
Thank you!
My advice if you want long shelf life hummus, would be to make a dehydrated product which comes to life when a little water is stirred in.

I wouldn't add any other preservatives unless your food scientist thought it was necessary.