Dates turning sour in vegan nutrition bars

Hello
I am developing a range of vegan nutrition bars and I am using 100% natural dates paste as sweetener.
Other ingredients I am using are nut butter, pea protein isolate, fructo oligosaccharide, cocoa powder and stevia.

I am observing that within 2 weeks the dates are turning sour and the bar doesn’t taste good. i would appreciate if someone can guide me about how to overcome this issue.

I am not providing any kind of heat treatment or freezing. the bars are packing in laminated pouch and stored at ambient conditions.

Does your date paste sterilized?

Looks like your bars had high Aw…Looks like there is no heat or very minimal. treatment there. whats tge internal temperatureof your bar during processing. …
How did you process it after forming into bars .
Did you apply GMP and other food safefty protocols during its preparation?

i have purchased it in bulk pack from reseller, its coming from UAE

You buy the dates but not the bars…explain how you make the bars.

whats Aw? there is no heat treatment involved. Havent measured the temperature. I simply packed it after making it into bars. Yes we followed GMP and food safety protocols. We sanitized the hands before handling the product and even sanitized the setup to make the bars.

What is your profession?

It seems you need a consulting service.

Your dates paste contains osmotolerant yeasts …spores thats the likelt cause of the spoilage.
Aw is water activity…

Yesterday we did another trial and this time we have used date syrup instead of date paste. I will ask my qc guy to check for water activity.

I own a food processing company and along with my team we are developing this new product range.

Sure. I am open to discussing this with a consultant.

We buy the date paste and other ingredients from market, blend all together and then roll them into bars

Thats not food safe as there is no heat treatment. Unless you subject that to irradiation to disinfecf it if you dont permit heat treatment.

Can you please suggest what kind of heat treatment should we go for? I have a jacketed blender in which I can heat the mixture, though not sure upto what temperatures and time? Also not sure how it will impact the overall texture of the bar

You should precook the bar mixture to reach an internal temperature of not lesser than 100C

For how long?

Depends how efficientt is your cooker …The temperature is your end point

Got it, will try and observe, thank you for the ideas

I have a question, if I heat the entire mixture to 100 c, won’t the date syrup caramelize and harden up?

Check caramelization temperature.

If the pH is acidic Maillards reaction responsible for off taste generation is not preponderant…Including also some liquid to prevent drying like syrups or even water might be advantageous. Try in lab scale before you do it in production scale to verify the feasibility.