How is it used compared to, say, a written standard?
Let’s say you are a large food producer and you have to make a pb&j sandwich. You are going to do a great deal of measurement, taste tests and other experiments to verify your sandwich is what it says on the box. Also packaging will be highly dependent and also even the nutrition label. Do you want to worry in the design phase that your sandwich has a variable consistency and weight ? No .
Its used for calibrating their instruments (or to validate the calibration of their instruments), which are THEN used to report on their products contents, which if they are found to be sufficiently in error there are adverse consequences.
Having a reference material whose composition is very certain is important here.
For example if you are a company that has lab equipment that analyzes the nutrition content of a food sample, they could use this peanut butter as a reference sample to make sure their equipment is properly calibrated.
The ability to put Facts on a "Nutrition Facts" label.
Sorta related: NileBlue's total laboratory synthesis of chocolate chip cookie: https://www.youtube.com/watch?v=crjxpZHv7Hk
Just check out the associated certificate, of the measurements it guarantees:
Here’s a video talking about that: https://youtu.be/YqYAWF7wd9k?si=OeNMVoU66ZvQUts7&t=658
It’s peanut butter, sure, but it’s not meant to be the peanut butter or even represent any particular peanut butter.
Instead, it comes with a detailed document describing all of the kinds of measurements you could take on it and their expected results. If you’ve got a peanut butter testing machine, you can put some in there and make sure it spits out the same result.
So, you’re not comparing any peanut butter against it, just your machine’s results against the results expected.
It’s easy to make peanut butter. It’s difficult to make each batch “chemically” identical! (Yes, chemically identical is impossible in a product like peanut butter, but identical enough for the purpose)
This is akin to selling a calibrated 1 kilogram cube of lead, with a precision of 1 nanogram and specified purity, for $1000. You are not just buying an overpriced $3 block of lead, but one that can be precisely used for calibrating machines, equipment, or processes.
For instance, peanut butter has aflatoxins -- known carcinogens. NIST's standard peanut butter has known levels of aflatoxins. By purchasing this peanut butter and testing it on your own peanut-butter-aflatoxin-sensing machine, you can calibrate your machine to detect aflatoxins in peanut butter to a reasonably high precision.
> Store at -20 C.
Yes, I do like my peanut butter deep frozen. It several hours of thinking prior to consuming the whole jar in one sitting.
Weird aside, my mother burned out her immersion blender attempting to reconstitute a jar of natural peanut butter. I now stir a few jars for her when visiting.
Is this probably just like peanut butter from one of the major peanut butter manufacturers, and then NIST just carefully measured and tested it?
> This Standard Reference Material (SRM) is intended primarily for use in validating methods for determining proximates, fatty acids, calories, vitamins, elements, amino acids, and aflatoxins in peanut butter and similar matrices. This SRM can also be used for quality assurance when assigning values to in-house reference materials.
> SRM 2387 IS INTENDED FOR LABORATORY USE ONLY, NOT FOR HUMAN CONSUMPTION.
> The SRM is a creamy peanut butter prepared by a manufacturer of peanut butter products.
> Source and Preparation: SRM 2387 is creamy peanut butter containing roasted peanuts, sugar, partially hydrogenated vegetable oils (48 % rapeseed, 40 % cottonseed, and 12 % soybean oil), and salt, and was prepared for NIST as part of a larger production run.
> An ordinary jar of peanut butter costs less than $5. And on the label you can see the ingredients and the amounts of different nutrients like protein, fats, sugar, and sodium. Those values have been measured by the manufacturer using different machines and analytical techniques. But how do you know those results are accurate? Well, this is where the government's standard jar of peanut butter comes in. It is mixed up so carefully and thoroughly that each jar contains exactly the same substance.
> "We take great pains at homogenizing these things. Make sure it's consistent."
> Then scientists at the National Institute of Standards and Technology, NIST, take years to painstakingly identify the quantities of all the different compounds in the peanut butter with specified uncertainties. This peanut butter is then known as a standard reference material or SRM. They sell these perfectly characterized SRM samples of peanut butter to researchers and manufacturers so they can calibrate their equipment. Essentially, the buyer knows that their equipment is working properly if, when they run the standard peanut butter, they get the values NIST supplies on the certificate.
> "We've spent a lot of time to make sure that we're confident and, you know, we can spend years studying the amount of fat in here and trying to figure out exactly what those numbers are."
> So what you're paying for is not really the peanut butter, it's the knowledge of exactly what is in the peanut butter.
> "And so this is what really drives the cost of a standard reference material is our ability to assert the truth. We produce what I call truth in a bottle."
