Looking for input on a food safety micro project on almond milks, oat milk and different flavored creamers using plant based ingredients
We are currently doing an experiment where we are trying to determine how long a product can stay in a blend tank and at what temperature should they be placed in without affecting the quality of product. Sometimes the product are left in the tank for 6 hours before they transferred to a silo that stores the product at lower temperature. The blend tanks currently are not jacketed so we want to see if temperature affects microbial counts and if we need to place time limits. Also, this project is being completed before pasteurization. We are hoping to use this results to also help our vendors to see if they can improve their counts on raw ingredients.
The set up of the experiment includes collecting samples after the first batch is made. The temperature of product is about 55-70 depending on the product as hot water is needed. we collect about 20 samples and place them in a water bath. 10 of them are plated every hour. The remaining are plated every 2 hours. We plate Aerobic, e. Coli, Coliform, yeast and mold and lactobacillus using the 3M petrifilms. We have used serial dilutions up to 10^5. So far, we have not detected any yeast and mold on any of the samples surprisingly. There are high counts (mostly TNTC) for other plates. We have noticed pH drops after about 4 hours.
We will be doing this for multiple products at different water bath temperature (50,60,70) and want to improve our methods everytime we repeat it. Are there any suggestions you may have on how you would conduct a similar project? If you need clarification on any step, please don’t hesitate to ask.
Akrishna - good morning and welcome!
I have a couple of questions. First, are you running control samples as well? Considering this is all pre-pasteurization, you could plate out the product after pasteurization to make sure all the relevant bacteria are being removed after pasteurization. I assume you do this already as a control point in your process.
Is there any way to cool down a sample to say 40 degrees and heat one up to 80 just to check the extremes?
I have a couple of questions. First, are you running control samples as well? Considering this is all pre-pasteurization, you could plate out the product after pasteurization to make sure all the relevant bacteria are being removed after pasteurization. I assume you do this already as a control point in your process.
Is there any way to cool down a sample to say 40 degrees and heat one up to 80 just to check the extremes?
Hi. We don’t plate a control. During our normal quality assurance process, we collected finished product from the line and plate those samples. Since the product in the bottles are pasteurized, we concluded a control is not needed.
We can heat up a sample in a water bath to extreme temperatures. In a way, that’s our plan, for each product, we’re going to repeat this experiment at different temperatures i.e. 50 F, 60, 70 F.
Eventually we also want to determine if size of tank has an effect microbial counts? Do you have any suggestions or know if size of tank can have that effect?