Operational procedure: Net quantity verification

Although the Safe Food for Canadians Regulations (SFCR) came into force on January 15, 2019, other requirements will be introduced in 2020 and 2021 based on food commodity, type of activity and business size. For more information, refer to the SFCR timelines.

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1.0 Purpose

The purpose of this document is to provide guidance to Canadian Food Inspection Agency (CFIA) inspection staff on how to verify that the net quantity declared on the label of a consumer prepackaged food is accurate and within the tolerances required by the Safe Food for Canadians Act and Regulations and the Food and Drugs Act and Regulations.

This document is intended to be used in conjunction with the Standard Inspection Procedures (SIP) and other guidance documents such as the General Principles of Sampling and commodity specific operational guidance.

The guidance outlined below should be used when verifying compliance of packaged food products, to aid in the assessment of a Preventive Control Plan (PCP) related sub-element, or follow-up to a complaint.

2.0 Authorities

The inspection powers, control actions and enforcement actions authorized by the above legislation are identified and explained in the Operational guideline – Food regulatory response guidelines.

3.0 Reference documents

4.0 Definitions

Unless specified below, definitions are located in either the:

Dry tare
unused, new tare materials.
Destructive inspection
means an inspection in which the container or product is destroyed, modified or rendered unusable.
Drained weight
means the weight of the edible contents of the container exclusive of free water, brine, pickling solution or glaze.
Wet tare
used product package that is cleaned in order to obtain the tare of the packaging material.
Weighted average
Corresponds to the sum of the average content of a sample and a statistical adjustment value. This adjustment takes into consideration the sample size and standard deviation in order to ensure a confidence level of 99.5%.

5.0 Acronyms

Acronyms are spelled out the first time they are used in this document and are consolidated in the Food business line acronyms list.

6.0 Operational procedure

The verification of net quantity declarations described in this document is applicable to consumer prepackaged food. The procedure does not apply to prepackaged food such as shipping containers and foods for institutional use. Such products are subject to the regulatory tolerances found in the Weights and Measures Act which is not enforced by CFIA. The SFCR net quantity sampling parameters and tolerances do not apply to these prepackaged foods unless they are resold at retail.

Most consumer prepackaged foods are subject to the minimum sampling parameters prescribed by SFCR 200 and Schedule 5 Part 1, with the tolerances for the actual net quantity prescribed by SFCR 199 and Schedule 4.

The exception is hermetically sealed processed fruits and vegetables which are subject to SFCR 197 and the requirements set out in the document titled Minimum drained weights and average drained seights for processed fruit or vegetable products in a hermetically sealed package. Refer to the Operational guidance: Processed products inspection for sampling plans and acceptance criteria for these products.

6.1 Prepare equipment

  • Electronic devices for performing calculations (tablets, calculators, Net quantity verification tool)
  • Weight kit
  • Volumetric kit (containing a pycnometer, graduated cylinder, beaker, etc.)
  • Thermometer
  • Sieve Footnote 1

6.2 Select a product to inspect

Select a consumer prepackaged product with a declared net quantity. The net quantity may be declared as a weight, volume or count, as required by the SFCR or FDR.

6.3 Determine the number of units in the lot (lot size)

Use the formula below to calculate the inspection lot size.

Number of units in the lot = no. of pallets × no. of cases per pallet × no. of units per case

6.4 Determine the sample size

The minimum acceptable sample size is described in Schedule 5 of the SFCR for consumer prepackaged products. For processed fruits and vegetables in hermetically sealed containers, refer to Appendix 1 of the Operation guidance: Processed products inspection.

6.5 Determine the tare weight (as required)

The tare is the total weight of the container and packaging material without the contents. The tare must be determined in order to calculate the net weight of prepackaged foods from the measured gross weight value.

Dry tare weight procedure for empty/unused packages

  1. Obtain 10 full sets of package components for the product, including labels, lids, plastic liners, tamper-evident bands, glue, etc.
  2. Weigh each full set of components and record the weights
  3. Calculate the average weight (tare weight)

Wet tare weight procedure for full/used packages

  1. Obtain 10 complete samples, including all package components
  2. Open the packages. Discard the product
  3. Wash the packages to remove any product residues. Avoid wetting labels and other absorbent packaging materials
  4. Thoroughly dry all package components
  5. Weigh each completely cleaned and dried package and record the weights
  6. Calculate the average weight, which will represent the tare weight

6.6 Prepare the sample units and determine net content

Follow the procedures found in the Appendixes that are appropriate to the type of consumer prepackaged food being inspected.

6.7 Determine compliance of the lot

Refer to the appropriate tolerance table to determine compliance of the lot inspected:

7.0 Appendixes

For general inquiries related to this Operational Guidance Document, please follow established communication channels, including submitting an electronic Request for Action Form (e-RAF).

Appendix 1: Retail prepackaged products sold by weight (catch-weight food)

For the purposes of this inspection procedure, a "retail packaged product" is any product that has been packaged, weighed and labelled in a retail establishment prior to purchase by a consumer, and for sale exclusively in that establishment (such as meat, fish, poultry, fresh fruit and vegetables).

The number of catch-weight retail packaged products in a lot may be very few in some retail establishments. In such cases, different products with same tare value may be combined to represent a lot.

For catch-weight food packaged at retail:

  • If there are less than 10 packages in the lot, select the total lot.
  • If there are more than 10 but less than 300 packages in the lot, select a sample of 10 packages from 3 randomly selected commodities.
  • If there are 300 or more packages in the lot, select a sample of 30 packages from 6 randomly selected commodities.
Note

A random sample could be chosen from a lot consisting of only one commodity when there has been a history of net quantity problems with one commodity.

Net content determination

  • For each sample selected, separate the packages into groups of the same tare and the same price per unit of measure to enable packages to be weighed with limited adjustments for the tare.
  • Measure each sample, ensuring the tare has been set on the scale.
  • When the tare weight value used represents the value of only one tare determination or the value from a predetermined tare weight table, the actual tare should be confirmed for each package which is found to be defective in quantity.

Appendix 2: Glazed frozen fish products

This general method describes a procedure to determine the net quantity of prepackaged glazed frozen products sold by weight (e.g. glazed shellfish, ground fish and crustacean products).

Sample preparation

  1. Remove package from storage, open and place product under gentle spray of cold water
  2. Agitate carefully, spraying the product until all glaze which can be seen or felt is removed
  3. After deglazing, transfer product to a sieve
  4. Incline the sieve at an angle of 20 to 30 degrees from horizontal and drain for a period of 2 minutes. This will remove the spray water from the product. The product remains frozen during this step

Net content determination

Transfer the drained product to a tared pan and weigh. The resultant figure is the net content for that sample unit.

Appendix 3: Frozen crustacean products immersed in water or brine sold by weight

One example of this type of product is known as a popsicle pack lobster.

Sample preparation

  1. Thaw the sample unit by submerging in cool running or circulating water until a core meat temperature between 10°C and 15°C is reached. This may be accomplished by using a sink with running tap water or a circulating water bath. Under some thawing conditions it may be necessary to allow the product to sit at room temperature until a minimum core temperature of 10°C is reached.
  2. After the product has thawed, as determined by a loss of rigidity, transfer the product to a sieve, distributing it evenly over the surface of the mesh, or for canned product invert over a beaker.
  3. Without shifting the product, incline the sieve or can at an angle of 20 to 30 degrees from horizontal and drain for a period of 2 minutes.

Net content determination

Transfer the drained product to a tared pan and weigh. The resultant figure is the net content for that sample unit.

Appendix 4: Frozen crustacean products or molluscan shellfish meats to which water or brine has been added to the final product

This general method describes a procedure to determine the net quantity of prepackaged frozen crustacean products or molluscan shellfish meats to which water or brine has been added to the final product (e.g. frozen canned lobster meat) sold by weight.

Sample preparation

  1. Open container of frozen product
  2. Place contents of individual package in a wire mesh basket and immerse in a container of fresh water at 26 ± 3°C such that the top of the basket extends above the water level The wire-mesh basket must be large enough to hold the contents of one package and with openings small enough to retain all pieces of the product
  3. Introduce water of the same temperature, (26 ± 3°C), at the bottom of the container at a flow rate of 4-11 liters per minute
  4. As soon as the product thaws, as determined by loss of rigidity, transfer all material to a sieve, distributing evenly
  5. Without shifting the material, incline the sieve to 30 degrees from horizontal in order to facilitate drainage

Net content determination

After two minutes, transfer product to a tared pan and weigh. The resultant figure is the net content for that sample unit.

Appendix 5: Non-frozen fish products packed in water, brine or vinegar

This process is applicable to certain canned and semi-preserved fish products.

Sample preparation

  1. Tare scale with sieve. After opening the container, transfer product in the sieve, distributing evenly over the surface of the mesh. Incline the sieve at an angle of 20 to 30 degrees from horizontal.
  2. Without shifting the product, drain for a period of 2 minutes.

Net content determination

Transfer the sieve containing the drained product on the scale and weigh. The resultant figure is the net content for that sample unit.

Appendix 6: Thick soup and chowder sold by volume

This process is applicable to soups and chowders that contain thick broth and solid food pieces.

Sample preparation

  1. Allow the sample unit to come to a temperature of 20°C.
  2. Open package and empty contents into a clean and dry container. Using a blender, blend the product contents until homogenized into a smooth and uniform mixture. Remove the air bubbles which may have formed during this process by slowly mixing the contents with a spatula.
  3. Determine the density of the product (see Appendix 14 for the procedure for determining the density)
  4. Repeat the entire procedure two more times and calculate the mean density.
  5. Calculate the equivalent declared net weight by multiplying the declared volume by the average density.
  6. Determine the tare of the package.

Net content determination

Weigh each individual unit and record this gross weight. Calculate the net weight for each unit.

Appendix 7: Washed drained weight

This process is applicable only to products which are presented for certification for export to countries that specifically require the net content determination to be conducted as a "washed drained weight".

Sample preparation

  1. Allow the sample unit to come to a temperature of 20 to 25°C.
  2. Open the package, tilt, and drain the sauce from the product. Transfer the contents to a sieve, distributing the product evenly over the surface of the mesh.
  3. Wash the contents of the sieve with hot water until the product is free of adhering sauce. Where necessary remove optional ingredients (spices, vegetables, fruits) with pincers.
  4. Without shifting the product, incline the sieve at an angle of 20 to 30 degrees from horizontal and drain for a period of 2 minutes.

Net content determination

Transfer the drained product to a tared pan and weigh. The result is the net content for the sample unit.

Appendix 8: Liquid or dry products sold by volume

This volumetric method describes a procedure to determine the net quantity of pre-packaged liquid or dry products of low viscosity (such as milks, juices, alcohols, vinegars) using the volumetric procedure.

This method is a destructive test and is applicable when the destruction of packages for test purposes poses no resource pressures on the industry and/or CFIA.

This method can be used as a cross reference for products found to be defective as a result of the gravimetric procedure for the verification of net quantity.

Sample Preparation

  1. The graduate must be conditioned before testing the product. To condition the graduate, fill it with an identical product being tested, then allow a 20 second drain time.
  2. Empty a sample package into a "to contain" graduated cylinder calibrated and allow a 30 second drain time.
  3. Before reading the volume content in the graduate, ensure:
    • temperature of product is at 20°C
    • graduate is on an even and level surface

Net content determination

Read the volume content in the graduate cylinder. The volume level measurement is taken at the bottom of the meniscus.

Appendix 9: Free flowing solids products - sold by volume

This volumetric method describes a procedure to determine the net quantity of pre-packaged free flowing solids labelled with a volumetric declaration of quantity (e.g. strawberries, blueberries, rice, powders)

This is a destructive method that does not apply to liquids or viscous products and is limited to packages having a volume of 1 liter or less.

Sample preparation

  1. Open each package carefully, if there is evidence of lumps in the product, break up with a spatula and mix well in the package.
  2. Gently pour the contents of one package into an appropriate size graduate, shake out any fragments of product which may be adhering to the sides of the package.
  3. Place the graduate on a level surface, without exerting pressure, level the product in the graduate.

Net content determination

Read the measure of the volume content in the graduate. This is the net volume for the product.

Appendix 10: Drained weight of canned fruits and vegetables

This method applies to canned fruits and vegetables subject to drained weight requirements Section 197 SFCR.

This method does not apply to canned bean, canned tomatoes and canned vegetarian beans.

Sample preparation

  1. Place the sieve in a clean drip tray, place both on the scale and tare the scale.
  2. Remove the sieve from the drip tray and place into an empty dish. Gently pour the contents of the opened container evenly over the screen of the sieve.
    • turn halves of peaches, pears or other fruit having concave surfaces so that the concave surfaces face downward on the screen to facilitate draining;
    • allow the container and its contents to drain into the dish for 30 seconds
  3. Place the sieve with the drained product in the drip tray.

Net content determination

Transfer the sieve and drip tray back to the tared scale and weigh. The resultant figure is the net content for that sample unit.

Appendix 11: Percent drained solids in canned tomatoes

This method is for the determination of the percent drained solids in canned tomatoes.

Sample preparation

  1. Weigh each unopened container and record the gross weight.
  2. Place an empty dish and the circular sieve on the scale and press the "tare" button.
  3. Remove the circular sieve, place it over a drain tray and gently pour the contents of the opened container evenly over the screen of the sieve.
  4. Without shifting the tomatoes, incline the sieve to facilitate draining of the juice.
  5. Allow the container and the tomatoes to drain into the dish for 30 seconds.
  6. Remove the sieve containing the tomatoes and place it back on the scale in the empty dish.

Net content determination

  1. Record the net weight of the drained solids on the worksheet.
  2. Wash and dry the empty container, weigh it (along with the lid and label) and record the weight on the worksheet.
  3. Calculate the total net weight using the following

    Total Net Weight = Gross Weight − Weight of the Empty Container

  4. Calculate the percent drained solids using the following formula:

    Percent Drained Solids = (Net Weight of Drained Solids ÷ Total Net Weight) × 100

Appendix 12: Percent drained solids in canned beans

This task applies to determine the percent drained solids in canned beans with pork, canned beans with pork and tomato sauce or vegetarian beans.

Sample preparation

  1. Weigh each unopened container and record the gross weight
  2. Determine the net weight of the drained solids
    1. Pour the contents of the opened container evenly onto the screen of the sieve.
    2. Wash the contents free of sauce with a gentle stream of warm water (approximately 60°C).
    3. Allow to drain 5 minutes.
    4. Gently tap the sieve to release entrapped water.
    5. Discard the liquid.
    6. Place the clean empty dish on the scale and press the "tare" button.

Net content determination

  1. Transfer the washed drained solids to the dish on the scale and weigh.
  2. Wash and dry the empty container, weigh it (along with the lid and label).
  3. Calculate the total net weight using the following formula and record the results on the worksheet.

    Total Net Weight = Gross Weight − Weight of the Empty Container

  4. Calculate the percent drained solids using the following formula

    Percent Drained Solids = (Net Weight of Drained Solids ÷ Total Net Weight) × 100

Appendix 13: 100 Bread/loaf screening method

The CFIA's screening method and tolerances were developed in association with the Bakery Council of Canada. In essence, instead of being granted a common moisture level for net quantity verification, bread is subject to a screening method involving extra tolerances (sometimes 2 times the current tolerances i.e. 28 g for a 680 g bread instead of the current 15 g tolerance) to compensate for the extreme variability of weights dependant on so many factors as the volume of the dough, its variable density (which changes as yeast produces its carbon dioxide), the air pockets, the time spent in the cooling chambers and in the oven etc.

Sample preparation

The sampling must be done in the bakery. The loaves may still be warm and may be wrapped or unwrapped. If the size of the lot to be sampled is:

  • 100 loaves or more, select 100 loaves from that lot for weighing
  • less than 100 loaves, select 13 loaves from that lot for weighing.

Specimens are to be selected randomly so as to represent that lot.

Net content determination

  • Unwrapped loaves should be weighed within 3 hours of removal from the oven.
  • Wrapped bread should be weighed within 36 hours of removal from the oven. If the bread is wrapped, the wrapper weight allowance should be that of the average of a minimum of 10 wrappers together with labels and closures if both are used.

Determine the tare weight of packaged loaves, weigh each container and record the gross weight

The lot will pass the screening method if all the following conditions are satisfied:

  • The average loaf weight must be equal to or greater than the declared weight.
  • A minimum of 51 loaves, in the case of a specimen of 100 loaves, or 7 loaves, in the case of a specimen of 13 loaves, must each have a net weight equal to or in excess of that declared.
  • No loaf declared as weighing 680 g may be short weight by more than 28 grams.
  • No loaf declared as weighing 454 g may be short weight by more than 20 grams.
  • No loaf declared as weighing any other weight may be short weight by more than an amount proportional to the 28 grams for a 680 g loaf rounded up to the next higher whole number of grams.

If these conditions are met, the lot passes the screening method. However, if a lot fails the screening method, proceed with the net quantity determination as described in 6.0 of this guidance.

Appendix 14: Gravimetric procedure for homogenous liquids sold by volume

The gravimetric procedure allows for the non-destructive net quantity verification of homogenous liquids by measuring the net weight of the product factored by the product's density.

Determine the density of the homogenous liquid

  1. Use a stainless steel pycnometer and wipe it clean with a soft, lint‑free cloth.
  2. Record the "certified pycnometer volume" (located on the calibration certificate) in the "Density Determination" section of the worksheet.
  3. Weigh the empty pycnometer, including lid, then record this value on the worksheet as "weight of empty pycnometer".
  4. Mix the specimen well in the original container. If necessary, transfer some product to another container for mixing. For high viscosity products, mix gently to avoid incorporating air into the product, as air will affect the density.
  5. Bring the temperature of the specimen to 20°C. This can be done by pouring approximately 200 ml of the product into a 500 mL beaker and heating or cooling the product (as the case may be) while stirring gently.
  6. Bring the temperature of the pycnometer to 20°C by immersing it in 20° C water.
  7. Dry the pycnometer thoroughly then fill with product at 20°C. For high viscosity products, tap the pycnometer on a flat surface several times to remove any air trapped in the product.
  8. Place the matching perforated lid on top of the pycnometer and seal it with a careful twisting motion.
  9. Wipe excess product from the pycnometer and lid with a soft, lint-free wiper.
  10. Weigh the loaded pycnometer and record this value as "weight of pycnometer and fluid" on the worksheet.

    Density = weight of sample ÷ volume of sample

Net content determination

  1. Convert the declared volume to net weight. This is accomplished by multiplying the declared volume on the product label by the density.

    Example: 200mL x 1.2 g/mL = 240 g

    This is equivalent to the declared net content of the product.

  2. Measure gross weight of the product in the container.
  3. Determine the net weight of the container.

Appendix 15: Miscellaneous

Alimentary Paste & Flour

The methodology used establishes common parameters under which current net quantity determinations with the applicable tolerances must be performed; i.e. at 13% moisture level for pasta and 14% for flour. These moisture adjustments are provided to establish a "level playing field" for manufacturers selling their goods from coast to coast where the temperatures and humidity fluctuate from a very humid environment to drier conditions. Imported pasta and flour products were also considered in the analysis.

Net quantity verification for flour does not require moisture adjustments when conducted within 16 hours after production; the same is true for pasta checked at manufacturing level within 24 hours. The moisture level determination for these commodities is done on premises with a moisture analyser called Compu-Trac MA-1 which is a combination of a computer and an electronic scale.

Sliced Smoked Salmon

  • Where the skin has been detached from the flesh of the product but is included in the package, the weight of the skin must be excluded from the net weight of the product.
  • Where the skin has been detached from the flesh of the product and is not included in the package, the net weight of the product shall be the total contents of the package.
  • Where the skin is still attached to the flesh of the product or is partially attached to maintain "kosher" requirements, the weight of the skin shall not be included in the net weight of the product unless the label indicates that the skin is included in the declared weight.
Note

The weight of the plastic dividers inserted between the smoked salmon slices shall be excluded from the declared weight of the product.

Dry Pack Lobster [definition: SFCR 262 (1)(c)]

Dry Pack is a term applied to lobster meat that has been vacuum packed, with no water or brine added to the final product.

Net weight would reflect the product as added to the container at the time of packaging. The product would be the shucked meat and nothing else. The product would not be subject to the removal of any liquid from the package to determine the net weight. Freezing and vacuum packaging of this product could result in some cryogenic drip. Include this liquid in the net weight determination.

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