Hot Fill vs. Tunnel Pasteurization
I am looking for some clarity on the difference between hot filling and tunnel pasteurization.
From all of the scholarly articles and research papers I have read, it’s seems that tunnel pasteurization is achieved when the internal temperature of the product at the coldest spot is at 165F and is held there for a period of time.
Hot filling recommendations are that the food or beverage be filled into the jar/bottle at no less than 180F.
I am trying to figure out why there is a 15F difference in process temperature?
Is this because when hot filling the beverage/food it will rapidly lose some heat when it is filled into the cold packaging? Or is this simply a measure of time/temperature/PUs? I’m just confused about why tunnel pasteurization can achieve the same goal with lower temperatures. I have seen no articles that advise hot filling at these temperatures.
Any insight is greatly appreciated.
I think that the main difference is that in tunnel pasteurization you are heat treating the container and the product. During hot fill, the product heat treats the container during the fill.
Hi Beveragequestions44,
Hot fill temperatures will be higher to ensure the entire inside contents of the package will reach the 165F pasteurisation temperature. This means the inside of the container, inside of the lid and airspace as well as the product. This will prevent most of the contamination from the air and packaging surviving. This technique requires a relatively strong container to prevent implosion as the product cools.
With tunnel pasteurisation everything reaches the 165F pasteurisation temperature.
Kind regards,
Tony
Also, a great deal of the difference has to do with the pH, brix and water activity of the product in question
Hence, you cannot/should not use research papers alone as they are not specific to your product
Example, previously, canned a product with a brix of at least 26 and a pH of 3.5 that product was hot fill, invert and hold
we also canned a product with a pH of 3.5 without an appreciable brix value, that product went through a tunnel pasteurizer