Guide to Developing Accurate Nutrient Values

2. Information on effects of processing

Many events occur during the processing of food products: moisture increases or decreases; nutrients are destroyed or washed away; fat may be lost or absorbed. The most important tools for calculating nutrient values from the data on your specific ingredients are your understanding of what happens to the ingredients during processing and the ability to reflect the impact of processing on nutrient content.

Accurate calculation of nutrient values for a product from the ingredient data depends on:

• accurate values for all relevant nutrients for all ingredients
• adjustments of fat and water to reflect their changed proportions in the product
• modifications of vitamin and mineral values in each ingredient to reflect the processing involved

When dry ingredients are simply combined and not further processed, the calculation may be very straightforward and adjustments of nutrient values are not required.

Changes in water can significantly affect nutrient content per unit of weight. If the water content of one or more raw ingredients is incorrect, or the loss/gain of water during processing is not accounted for properly, the concentrations of nutrients calculated for the finished product will be incorrect.

The USDA Table of Nutrient Retention Factors, Release 5 (2003)²⁴ is a good source of information on retention of vitamins and minerals in processed foods. Applying these factors to the amounts of vitamins and minerals in raw ingredients generates approximate amounts likely to remain after processing. For more information on applying retention factors, see Appendix E.

Successful calculation of nutrient values requires expertise. You may choose to perform nutrient calculations in-house or to contract them out to a dietitian or food scientist with expertise in calculations of product formulations using an appropriate software program. Be sure to ask what type of software they plan to use, as not all types do a good job of accounting for processing factors. Additional information on choosing a consultant can be found in Appendix C.

B. Assessing the Data

It is important to assess both the quality and the specificity of the data you will be using. The source of the data used in any calculation must be well understood. It is important to know if the data are product-specific or generic. Many considerations will apply in either case, but some will be specific to the source.

You need to ensure that the information you have is accurate. You should review all incoming data and resolve any discrepancies such as the precision to which the data are reported (i.e. rounded values or laboratory values) or whether the values seem reasonable compared with the initial point of reference you established.

You may want to request laboratory analysis to validate the nutrient values in your ingredients. You also can validate your final results using laboratory analysis of your finished product, following the sampling and analysis approach described in Part 2, Chapter III (page 39). If values are missing for some nutrients, you will need to have the samples analyzed. If you are not obliged to report a nutrient, you may leave it out of your calculations if critical information on raw ingredients is missing.

1. Supplier information

When calculating nutrient values based on ingredient information, it is generally preferable to use the nutrient information from your ingredient suppliers, as this is more likely to represent the product you are using. Some suppliers of fresh fruits and vegetables, meat, poultry, fish and seafood, and alcoholic beverages are not required through federal regulations to provide nutrient information. You may want to add this requirement to your contract, or you can consult alternative sources of information, such as generic databases, for those foods.

The values provided by your suppliers may come from their own databases of laboratory analysis data, from a calculation using ingredient information, or from values taken directly from a generic reference database. Data from direct laboratory analysis is preferable, as it will represent the actual ingredient that you are using and will allow you to further manipulate the values in a database. It is advisable to obtain more information on how the supplier's values were developed and what they really represent:

• Are the values specific to your ingredient or to a similar ingredient, or are they generic values for a mix of products? If the values represent the exact ingredient you are using, your final values are more likely to represent your product.
• Were enough samples used to generate the values?
• Did the samples reflect the current products, ingredients and test methods?
• Did the sample design capture the key sources of variation?
• Is the value presented an average or median?
• Is there any indication of the variability, or the range?
• Are validation data available to show that the numbers are likely to be correct?

In addition, nutrition information provided by suppliers must "be stated with a degree of precision that corresponds to the accuracy of the analytical methodology used to produce the information".²⁵ Information rounded according to the rules of declaration in a Nutrition Facts table would not be acceptable because of the additional approximation it would add to your own calculations.

• For example, if your product contains five ingredients that each contain 0.4 g fat/serving, each ingredient would report zero amounts of fat in its individual Nutrition Facts table, due to the rounding rules. However, when you combine those ingredients, it would not be correct to report zero fat, as you would likely have more than 0.5 g fat in your finished product.

2. Reference databases

In some cases, generic information from a reference database is acceptable, especially if the ingredient or nutrient does not exhibit much variability. Granulated sugar and butter are examples of ingredients that do not vary significantly from one supplier to another, their profiles being defined in Canadian food regulations.

Reference databases are accompanied by extensive documentation describing the type of data (analytical, calculated, imputed) and the source of the data. They also usually indicate the possible range or variation around the mean or median. Although the presentation of this documentation varies among national databases, all follow established international standards²⁶ for collecting and relaying this information wherever possible. All of the documentation should be examined by the user to assess whether the data are suitable for a particular application.

Before using generic information in your calculation, you should verify the following features:

• The information should be available for all nutrients of interest. If a record is missing, it should be noted; a zero should not be used unless the amount is zero.
• The data should be up-to-date and reviewed by personnel with knowledge and experience in the area.
• The source of the data should be recorded and available.
• The database values should be based on analytical data, unless generic data are sufficient (as in the case of sugar or butter).
• The units of measurement should be metric, for consistency when combining ingredients.

Generic information is also acceptable for providing nutrient information to consumers for a generic category of products, such as pink grapefruit. Yet, the values must be representative of the category of foods. Because the nutrient content of these products may exhibit important variation, final values may need to be adjusted for nutrition labelling purposes (see Part II, Chapter V, page 64 ).

3. Commercial databases

Information from a commercial database may be used with caution for some cases where the ingredient or nutrient does not exhibit much variability. You should check the source of the information you intend to use. Commercial databases tend to supply one value with little information about the data type, source, or representative sample sets. Many will provide the source as "from USDA" or "from Heinz", but for actual information on where USDA obtained the data or what kind of sampling went into the Heinz values, you have to consult these original references. Data from one record are often "borrowed" or extended to another similar food to avoid missing values, with no explanation of the standards or assumptions for doing so.

C. Combining the Data

You will need to customize your own database of ingredient information. The complexity of this task depends on your product, the number of ingredients and the processing steps. The task could be quite simple, such as keeping a file folder of information on each ingredient. It could also be more complex and benefit from the use of a commercial software package to make the calculations more efficient, help in accounting for the processing effects, and make it possible to fill information gaps with generic information from a commercial database.

Calculations for determining the nutrient value of a finished product generally involve adding the nutrient contribution of each ingredient and then making allowances for processing effects (such as moisture loss from baking or fat addition from frying).

1. Entering the ingredient information

Using a spreadsheet
For a product with a relatively simple formulation, you can make a chart such as the one shown below. For all ingredients, you enter the amount of each nutrient of interest in a set amount (e.g. per 100 grams) and convert this to the final amount in your product, then simply sum the contribution of each ingredient. You can then convert this to the amount per serving.

Sample Chart for Tracking Ingredient Information

Nutrient	Product: Dry Cake Mix
	Flour		Sugar		Baking powder		Salt		TOTAL Amount
	Amount		Amount		Amount		Amount
	In 100 g	In product	In 100 g	In product	In 100 g	In product	In 100 g	In product	In product	Per serving
Weight (g)	100	300	100	340	100	12	100	6	658	60
Calories (kcal)	360	1080	400	1360	137	16.4	0	0	2456.4	224.0
Fat (g)	1	3	0	0	0	0.00	0	0	3	0.3
Saturated Fat (g)	0.35	1.05	0	0	0	0.00	0	0	1.05	0.10
Trans Fatty Acid (g)	0	0	0	0	0	0.00	0	0	0	0.00
Cholesterol (mg)	0	0	0	0	0	0.00	0	0	0	0.00
Sodium (mg)	2	6	0.9	3.1	3579	429.5	38758	2325	2764.0	252.0
Carbohydrates (g)	75	225	100	340	34.2	4.1	0	0	569.1	51.9
Dietary Fibre (g)	3	9	0	0	0	0.00	0	0	9	0.8
Total Sugars (g)	1	3	100	340	0	0.00	0	0	343	31.3
Protein (g)	11.6	34.8	0	0	0	0.00		0	34.8	3.2

For products that are more complex (e.g. if a product has many ingredients or if you need to take into account processing effects such as retention factors), it may be useful to use an electronic spreadsheet or computer program that will help you to do the calculations more efficiently.

Using a commercial software program
While software programs can make the job of calculating nutrient values easier and more efficient, they must be selected carefully in accordance with your needs. Note that they are useful for nutrition labelling only if they enable you to add your supplier-specific information to the database. The following are some of the other critical features that should be included:

• You should be able to customize your own ingredient database by adding nutrient data and other pertinent information on desired foods, supplier ingredients, and so on.
• As nutrient values may change during storage or processing, there should be provision for incorporating retention factors, and their source should be noted. Retention factors are discussed in more detail in Appendix E.

A few other features that may assist you include:

• the ability to add other nutrient fields and notes
• protection against overwriting data when the software is updated
• ingredient name fields large enough to permit meaningful description
• the ability to export data easily into a spreadsheet program

Further details on the critical features to consider when choosing databases or software can be found in Appendix H.

2. Entering the formulation information

Once all of the ingredients are entered into the database, you can enter the specific formulation for the product of interest. You must enter all ingredients so that the complete formulation is included. If required, you should adjust nutrient values by applying retention factors for vitamins and minerals that reflect your processing methods. Fat and moisture content and final weights need to be adjusted in accordance with your processing conditions.

The next step is to calculate unrounded values per 100 grams of finished product. It is important to check whether these values appear reasonable. One way to do this is to compare these values with those for similar products.

Further treatment of the data specifically for nutrition labelling can be found in Part 2, Chapter V (page 64).

D. Keeping Detailed Records

It is important to keep records of your ingredient information, product formulation and nutrient content calculations. It may be possible to incorporate this into your software program or it may be more efficient to use an electronic spreadsheet. In any indirect method, it is important to record the sources of your information, how the effects of processing were taken into account, and whether laboratory analysis was used to validate the results.

Some of the information that should be kept for a minimum of two (2) years is outlined in the chart below.

Information to Be Kept for a Minimum of 2 Years

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V. Data for Nutrition Labelling

A. The Nutrition Facts Table

One way that nutrient data are used for nutrition labelling is in the creation of Nutrition Facts tables (see Figure A).

Nutrition Facts tables must be included on most prepackaged foods, giving consumers information on the nutrient content of those food products. This information, displayed in a standardized format and in the same order, includes Calories and rounded nutrient values for a stated amount of food. Thirteen core nutrients are always part of the declaration; there is also a "closed" list of other nutrients that may be provided. The information must appear in both English and French.

Depending on the nutrient, the value must be expressed either in absolute units of measurement (e.g. grams, milligrams) or as relative amounts (percentage of the reference Daily Value; % DV), or both. Both absolute units and % DVs are subject to rounding rules.

Figure A: Sample Nutrition Facts table

1. Nutrition Facts table: core information, standard format

For information about nutrient definitions, the core information required, additional permitted nutrients, conditions for the inclusion of certain nutrients, units of expression and rounding rules, see the CFIA 2003 Guide to Food Labelling and Advertising²⁷ or Sections B.01.401 and B.01.402 of the Food and Drug Regulations.²⁸

2. What are Daily Values (DVs)?

Daily Values (DVs) are reference values based on recommendations for a healthy diet. The Daily Value is equivalent to either the Recommended Daily Intake (for vitamins and mineral nutrients) or the Reference Standard (for other nutrients).

The % Daily Value is a simple benchmark for evaluating the nutrient content of foods quickly and easily. When the nutrient content is expressed as a percentage of Daily Value (% DV), the consumer can see whether there is a lot or a little of a nutrient in the specific amount of food. Note that % DVs are not stated for all nutrients; they are required for fat, total saturated and trans fatty acids, sodium, carbohydrates, fibre, Vitamins A and C, calcium and iron. The reference values for computing % DVs can be found in the 2003 Guide to Food Labelling and Advertising.

3. What must be included in a Nutrition Facts table?

The Nutrition Facts table lists Calories and 13 core nutrients in a consistent order. All of the information in the Nutrition Facts table must be based on a stated serving of food. Regulated reference amounts of food can help in setting a serving size.

Certain other nutrients also may be included (a "closed" list). It becomes mandatory to declare these nutrients if they are added to the food or if they are the subject of a claim.

• Except for vitamins and mineral nutrients, the label indicates the actual amount (quantity) of the nutrient in the stated serving of food. Even if the nutrient amount is zero, it is listed.
• For vitamins and mineral nutrients, the nutrient content is expressed as a percentage of a reference value, the Daily Value. The % DV gives a context to the actual amount of a nutrient.
• For a few nutrients, both the actual amount and % DV are provided.