Food Engineering/Manufacturing/Cold Fill Vinaigrette


I have a vinaigrette that I first bottled with a copacker with a hot fill.  This process broke the product, so we decided to try to get testing to see if we could do a cold fill on the product. We  had a letter from Party #1 stating that they reviewed our formula and and preparation procedures and they concluded that our vinaigrette was an acid food.  And that we were exempt from the FDA regulation promulgated in Title 21 code of the FDA parts 113 & 114. Also that our product could be successfully formulated and packed without the need for thermal stabilization process due to the high concentrations of organic acids and very low ph. Endemic pathogens should die off  quickly.  But should not ship product within 7 days following production.   We did an actual shelf life testing Party #2  for 4 months--after the 4 months the Lactic Acid Bacteria was <200, Organoleptic Abnormalities were Absent and Yeast Mold Count (DRBC Plate) were <100.  We did an accelerated shelf life Party #3 , with good results, but was told I could not get a completed evaluation until we gave a finished product to them.  Which we did, we did the cold fill and bottled our an accelerated shelf life test  Party #3 with  results --predicted shelf life of 1 year.  The ph was 3.23 and water activity .979. (although when we bottled the product we got a ph of 3.17).  This was great news, So I receive my letter in the mail from Party # 3, and it states the results, but it states that processing conditions should be heated to 180 degrees for longer than 15 seconds and at bottling temp applying the caps... we never talked with Party #3 above hot fill all of our correspondences to talk about cold fill, so year later--and much money spent--I feel as though I am at square-1.  I still have the info from Party # 1 and #2, although Party #1 has since retired (although I have a message into the person that has taken over, but it is the holidays).  Party # 3 said she never remembers talking about it being cold fill (but like I said, I have info from her stating that), also she since says she has talked with the FDA and my only option would be to hot fill as it is not a acid food.  or to do a challenge study (don't know what that entails or how long that takes).  Of course this comes as I am days away of getting this product into a big store.  I am really worried and was hoping you might have so insight for me.  Thank you

This is a complex case, with apparently conflicting opinions from experts. It is difficult for me without access to the exact formula, but assuming that, as a vinaigrette, it is mostly vinegar, with some oil and herbs, it is likely that Party #1 is correct and it is an acid food. If so, then you are not required to file a process with FDA. However, you are still required to make a safe food. As an acid food, there is no threat from Clostridium botulinum, but some other pathogens could survive for short periods. FDA has accepted cold fill filings for products with pH below 3.3 on the basis of published research. Party #2's suggestion of seven days hold is very conservative; other products show complete die off of pathogens in 24 hours or even less. Party #3 seems to feel it is not an acid food, but even if she is correct, all you need do is file your cold fill process for an acidified food supported by a process authority who could cite Breidt et al 2007 (Breidt, F., J. Hayes, & R. F. McFeeters. 2007. Determination of 5-Log Reduction Times for Food Pathogens in Acidified Cucumbers during storage at 10 and 25 [deg] C. Journal of Food Protection 70 (11) p. 2638-2641).

Party #1 or Party #2 may be process authorities. If not, I am, and you can reach me at You can safely make your product for sale, in my opinion. To be safe with FDA, you can file your process. They will tell you whether you need to or not. The issue about filing is how much of the formula is vinegar. There is no question that at 3.23 pH, it is a high acid food; the distinction is whether it is naturally acid or acidified. I regret to say that Party #3 is giving you incorrect advice. I do not believe you need a challenge study, as it is well established that high acid foods are safe and shelf stable.  

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J. Peter Clark


How various processed foods are made; ways to improve manufacturing; how to make a new food product.


Employment history: Research Engineer, U.S.Agricultural Research Service, Associate Professor Chemical Engineering, Virginia Tech, Director of Research, Continental Baking Company, President, Epstein Process Engineering, Inc., Vice Presdent Technology, Fluor Daniel, Inc., Consultant to the Process Industries

Organizations: American Institute of Chemical Engineers (Fellow) Institute of Food Technologists, American Association of Cereal Chemists, American Association of Candy Technologists, American Society of Agricultural Engineers,

Publications: Several Encyclopedias (Kirk and Othmer, Chemical Technology; Food Science, Food Technology and Nutrition; Wiley Encyclopedia of Food Science and Technology; Encyclopedia of Life Support Systems); five books, two book chapters; numerous journals.

Education: BSChE Notre Dame PhD University of California, Berkeley

Awards: AIChE Food, Pharmaceutical and Bioengineering Division Award 1998

Clients: Major food processing and pharamaceutical companies.

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