Submitted by anogre8me t3_zvpi8q in todayilearned
This is my job. 3 rodent hairs per 100g of tomato paste is allowed. 4 is a fail. Insect fragments, there is no limit. 1 rodent hair with skin still attached to it is automatic fail.
In 6 years I haven't seen any skin still attached to a hair. 2017 was the worst year I've seen, alot of samples with 4 hairs or more. This year wasn't too bad.
But also, its all really random. You can't use the product after testing it so only a portion is tested representing a huge sample size. If a "fail" sample was to be retested, it would very likely have nothing in it. If a passing sample was retested, it wouldn't be surprising at all to come up as a fail.
How exactly does one count rodent hairs in tomato paste?
First you extract them, then you read them under a microscope.
Extraction: add 100g tomato paste to 2L Wildman trap flask, add 20 mL castor oil (the light filth sticks to the oil), add water to neck of flask, stir, let it sit for 30 min, stirring every 10 min, trap upper inch of sample (the oil floats with the filth attached) and decant into beaker, raise water level again, let it sit 10 min, repeat decanting, repeat this step, then discard the water in the 2L flask and add fresh water and the sample in the beaker that you have decanted. Let it sit 10 min, decant one last time. Finally, filter whats in the beaker through a circular filter paper connected to a vacuum, this way they water and oil goes through, leaving just the light filth and tomato pulp. That filter paper gets read under a microscope, count the pieces you find.
This is fascinating. Thanks for answering.
Absolutely
I’m curious, does your job ever affect the way you feel about food, or eating in general?
Not me. But thats more to do with me than the job. I'll eat almost anything if it tastes good. Some people in the department it definitely does turn them off of certain products.
Other things I've learned in the job include: peanut products have consistently high levels of aflatoxin, which can cause cancer. Same with Mexican pumpkin seeds, or pepitas. Brazil nuts have "rancid" results very consistently, regardless of how fresh they are. On the other end of that, coconut oil seemingly never goes bad. We have had a shelf life sample the entire 6 years I've worked there that is still the same low levels of rancidity as when it was started.
No, no, don't stop.
Ummmm...I shared most of what I could think already but ill try with some more tidbits.
2% milk often actually has 1.5-1.99% fat.
The leftover ground almonds that we test for aflatoxin often end up in makeup products, I've been told. We sell the ground almonds cheap and I think they use the oils.
Almonds that fail aflatoxin testing often end up in cow feed. Because of that, dairy products need aflatoxin testing too. But don't worry about that one. Somehow the levels don't really transfer to dairy products. But....if it does, its in such low levels that it won't affect adults, but could affect infants. And so there are different detection levels required if the product is specifically meant for infants. Other than a cows digestive system essentially diluting the aflatoxin levels, bleach is the only thing that will kill it. Quick harvest and proper storage conditions of almonds is important in keeping these levels low, because it grows on mold.
In butter, moisture, fat and salt testing is done in a series of tests without needing to test separate portions for each test. Its called the Kohman method.
Fat testing in meat is done in an apparatus called Soxhlet. Visually, I think it looks like Walter Whites set-up in Breaking Bad.
So I need to bleach my baby’s milk, good to know, good to know.
writes this down
This is so interesting, I’ve wondered in the past how they measure these things. Thanks for sharing!
But products contain fats, carbs, and proteins- everything that a bacterium needs to grow. Coconut oil is just mono-, di-, and triglycerides of caprylic and capric acid so unlikely that anything could grow on that.
In chemistry, fat and oil are interchangeable terms. The oil oxidizes and goes rancid. Coconut oil doesn't oxidize anywhere near as fast as others.
The point I’m making is that you need all 3, whereas coconut oil only has 1. Yes, being capric and caprylic vs linoleic, linolenyl, or ricinoleic acid esters would indeed preclude oxidation. But you can get this from basically any hydrogenated oil, be it palm oil or soybean oil.
I have a feeling you have more in depth knowledge than I do. But all I can say is that we do the same testing on palm oil. The tests are Free Fatty Acid and Peroxide Value. Palm oil results start to rise in a few months, and coconut oil hasn't risen in 6 years.
Edit: there may be more variables at play than I am aware of. But in our lab, they have the same storage conditions.
Yes the palm oil is rich in oleic, linoleic, etc. but fully hydrogenated palm oil (e.g., stearine) should not show oxidation due to the lack of double bonds.
A TIL inside a TIL
What does one study to qualify?
I work in the chemistry department. But they hire anyone with a degree in any science, ideally. And essentially any college degree can get you hired in the company. They also hire people with HS diploma at assistant levels and are willing to promote and train you if you put in the work. I only have a HS diploma.
My department manager was an engineering major. Actually, less than half of the department went to school for chemistry.
Edit: I should clarify that the test was originally part of our "food safety" department but that department is 1/5th the size of the chemistry department so they trained us and transferred the testing to the larger department. We also have a microbiology department but they are already understaffed and have to work 10-16 hour shifts, they couldn't take it on.
Probably quality assurance and food standard regulation certificates
One, two, and then - wait for it - three.
"The really gross part is that rodents don't shed" or so they always told us years ago.
this isn't accurate, rodents do shed. rats shed all the time when they clean themselves it's just not noticed because of how how fastidious they are about cleaning
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