What are the NCI National Cheese Colour Standards?

“Monterey Jack cheese….natural white, not darker than #2 using the National Cheese Institute Colour Chart … Cheddar cheese….natural colour, not darker than #9 using the National Cheese Institute Colour Chart…” www.farmdale.net

“…initial point of sale for: Cheddar cheese in 40 pound blocks, colored between 6 and 8 on the National Cheese Institute colour chart…” www.cmegroup.com

“…Feta is white in colour, is a bit sour to the taste and rich in aroma … Fresh Asiago has an off-white colour and is milder in flavor than mature Asiago. Mature Asiago also has a more yellowish colour and is somewhat grainy in texture … Cream cheese is usually white in colour and is available in low-fat or non-fat varieties … Blue cheese….is spotted or veined throughout with blue, blue-gray or blue-green mold, and carries a distinct smell….” www.idfa.org

The National Cheese Institute’s Colour Standards are a series of 12 Munsell colour chips initially intended for the visual colour grading of hard cheese.  Additionally it has been applied to the colour of products from soft cheese spreads to condensed milk.

The National Cheese Institute is part of the US International Dairy Foods Association (IDFA), which also represents the Milk Industry Foundation and the International Ice Cream Association.

The colour quality concern for cheese products is colour uniformity within a lot, and colour consistency from lot-to-lot.

In a well-lighted area, preferably daylight balanced, a person would assign the nearest NCI grade based on a visual comparison between the printed chart and the sample cheese colour.

The NCI Cheese Colour grade provides a more systematic and consistent method of colour communication for cheese products than the random vocabulary of individual people and serves as a basis for purchase of large quantities of cheese products.

Source for NCI National Cheese Colour Standard Chart

The NCI chart is commercially available from:

Nelson-Jameson Company, Marshfield, WI 54449 USA www.nelsonjameson.com  (Product # 170-4900)

Degussa BioActives, Waukesha, WI 53187 USA www.foodingredientsinc.com

FAQ: “Do you have Hunter L a & b values that correlate to the NCI cheese colour standards? We have NCI Colour specifications for our cheese products. I would like to translate them into Hunter Lab specifications… so that we can get continuous rather than categorical data and better control our quality. The NCI Colour chips are too small to cover the Hunter window… so we can’t just scan it…”

We view the NCI Colour Scale as a visual matching and reporting scale with less precision (only 12 steps) than a colorimetric colour scales that come with your colour measurement instrument. If you stay with the intended use of this scale which was to visually categorize cheese colour for product contractual description, it works fine.

You would think it would be easy to develop a colorimetric correlation to the NCI Cheese Colour Scale by directly reading in the cheese colour chips in Hunter L, a, b or CIE L*, a*, b* on your instrument and then working out a direct correlation to this NCI visual scale. This is not the case.

There is a difference between the cheese colour chips which are solid and opaque and block cheese is slightly translucent (or light trapping). This introduces a bias in your measured values to visual NCI assignment such that if you have a cheese sample that is a perfect visual match to one of the NCI colour chips and you measure both chip and cheese, you will find that the measured colour values will not be the same. Light is being slightly trapped in the translucent cheese and distorting the measurement match.

The best way to create an NCI Cheese Colour correlation to measured colour values is to take a wide range of cheese samples covering as wide a range of NCI colour as possible. Using a group of cheese colour experts, visually assign NCI Colour ratings (average group opinion is best) to the cheese samples using the visual NCI Colour chart. Then measure the cheese samples on your HunterLab instrument using Hunter L, a, b or CIE L*, a*, b*. Develop a correlation between the measured cheese values and the visually assigned NCI ratings for those same cheese samples.

NCI Colour is a single 12-step reporting scale common to the cheese industry but less precise than 3D colorimetric colour scales such as CIE L, a, b* or Hunter L, a, b. If you are looking to verify colour consistency in your cheese product over time, the best way is to use CIE L, a, b* or Hunter L, a, b colour measurement which will tell you more about the lot colour variation of your product and with greater precision.

If you develop an NCI Colour correlation using the above method, you can report this in addition to clients who wish this NCI rating. Alternatively, you can assign an NCI colour rating visually.