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Control recommendations for the inactivation of Trichinella spiralis in pork products

Although the Safe Food for Canadians Regulations (SFCR) came into force on January 15, 2019, certain requirements may apply 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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Introduction

The purpose of this document is to provide information on measures for the destruction of Trichinella in pork products. Trichinella spiralis larvae may be destroyed by curing, heating and freezing.

A. Curing

The curing methods described here are designed specifically to ensure that viable Trichinella are destroyed in sausages and meat products containing striated pork muscle tissues. These methods do not guarantee the safety of product in terms of other pathogens such as Salmonella spp., Toxoplasma gondii, E. coli and L. monocytogenes, etc.

A.1 Sausages

A.1.1 Method # 1 (Cured and Dried Sausages)

The meat is ground or chopped into pieces of no more than 1.9 cm (¾ inch) maximum in diameter. A minimum of 3.33% of salt per weight of unstuffed sausage material is mixed thoroughly with the ground or chopped meat.

A.1.2 Method # 2 (Cured, Smoked and Dried Sausages)

Meat is ground into pieces of 1.9 cm (¾ inch) maximum diameter or less. A dry-curing mixture containing a minimum of 3.33% of salt per weight of unstuffed sausage material is mixed thoroughly with the ground or chopped meat. After stuffing, sausages are smoked a minimum of 40 hours at a temperature not lower than 26.7°C.

After smoking, sausages having a diameter not exceeding 8.8 cm (3½ inches), measured at the time of stuffing, are held in a drying room for a minimum of 10 days at a minimum temperature of 7.3°C. Sausages are not to be released from the drying room less than 18 days from the time curing materials are added to the meat.

After smoking, sausages in casings exceeding 8.8 cm (3½ inches) but not exceeding 10.2 cm (4 inches) in diameter at the time of stuffing are held in a drying room for a minimum of 25 days at a minimum temperature of 7.3°C. Sausages are not to be released from the drying room less than 33 days from the time the curing materials are added to the meat.

A.1.3 Method # 3 (Cured and Smoked Sausages)

Meat is ground or chopped into pieces of 1.9 cm (¾ inch) maximum diameter or less. A dry-curing mixture containing a minimum of 3.33% of salt per weight of unstuffed sausage material is mixed thoroughly with the ground or chopped meat.

Total curing time is no less than six days; this six-day period includes:

Smoking of sausages is mandatory in this process.

A.1.4 Method # 4 (Cured and Dried Sausages with optional cooking or smoking)

Meat is ground or chopped into pieces of 0.6 cm (¼ inch) maximum diameter. A dry-curing mixture containing a minimum of 2.5% of salt per weight of unstuffed sausage material is mixed thoroughly with the ground or chopped meat.

After adding the mixture with the curing salts and before stuffing, the ground or chopped meat is held as a compact mass of a depth of 15.2 cm (6 inches) or less at a minimum temperature of 2.3°C for a minimum of ten days. At the end of this holding period, sausages are stuffed in casings or cloth bags not to exceed a maximum diameter of 8.5 cm (3 ⅓ inches), as measured at the time of stuffing.

At any time after stuffing, the operator may choose to:

After stuffing, sausages are held in a drying room at a minimum temperature of 7.3°C for the remainder of a 35-day period, measured from the time curing materials were added to the meat. The time spent smoking or heating sausages are not to be included in the 35-day holding/drying period calculation.

A.1.5 Method #5 (Sausages with coated casings or coverings)

Meat is ground or chopped into pieces of 1.9 cm (¾ inch) maximum diameter. A dry-curing mixture containing a minimum of 3.33% of salt per weight of unstuffed sausage material is mixed thoroughly with the ground or chopped meat.

After stuffing, sausages are held in a drying room at a temperature no lower than 7.3°C for a minimum period of 65 days.

The casings or coverings for sausages prepared according to this method may be coated, before or during the drying period, with paraffin or other suitable substance.

A.1.6 Method # 6 (Dry Cured Sausage; optional cooking or smoking; optional reduced salt formulation)

A.1.6.1 General Recommendations:

Meat is ground or chopped into pieces of 1.9 cm (¾ inch) maximum diameter. A dry-curing mixture containing a minimum of 3.33% salt per weight of unstuffed sausage material, excluding the weight of dry ingredients, is mixed thoroughly with the ground or chopped meat. Salt concentration for this method is calculated with the following formula:

Salt concentration = [weight of salt in sausage formula ÷ (weight of sausage formula – weight of dry ingredients)] × 100

The result is rounded down to the next lowest 0.1%

Example:

Formula: 120 kg pork, 3.56 kg salt, 2 kg spice, 0.5 kg wine, 1 kg water and starter culture, 0.8 kg sugar, 0.012 kg sodium nitrite.

Salt concentration = [weight of salt at 3.56 kg ÷ (weight of formula at 127.872 kg – weight of dry ingredients at 6.372 kg)] × 100
= 0.0293 or 2.93%; (2.9%)

After mixing, sausages are held for two time periods:

Note: The 48-hour holding period can take place entirely or partially before the beginning of the drying period. If the holding period is not completed before the beginning of the drying period, that part which remains is completed either after the end of the drying period or as an extension of the drying period.

Table A.1.6.1 – Sausage drying times by Method # 6 (baseline table)
Maximum diameter of casing at time of stuffing Table Note 1 in cm (inches) Minimum holding time in drying room (room temperature ≥1.7°C) Minimum number of days in drying room (room temperature ≥10°C)
2.5 cm (1.0") 48 hours 14 days
3.8 cm (1.5") 48 hours 15 days
5.0 cm (2.0") 48 hours 16 days
6.3 cm (2.5") 48 hours 18 days
7.6 cm (3.0") 48 hours 20 days
8.8 cm (3.5") 48 hours 23 days
10.1 cm (4.0") 48 hours 25 days
11.4 cm (4.5") 48 hours 30 days
12.7 cm (5.0") 48 hours 35 days
13.4 cm (5.5") 48 hours 43 days
15.2 cm (6.0") 48 hours 50 days

Table Note

Table Note 1

The drying time for flattened or oval sausages is calculated from a diameter derived by measuring the circumference and divided by 3.14 (pi).

Return to table note 1  referrer

A.1.6.2 Reduction in the number of drying days for sausages which are smoked or fermented during the holding period

Sausages fabricated according to the methods outlined in sections A.1.6.1 and A.1.6.3 may be smoked or fermented between the time curing materials are added and the time drying commences. If the internal temperature of the product is increased to 21.1°C or higher during the 48 hours holding period and maintained according to one of the time/temperature combinations described in Table A.1.6.2 below, the drying time prescribed for the product may be reduced.

Interpolation of these values is not acceptable.

Table A.1.6.2: For sausages manufactured according to Method # 6 which are smoked or fermented during the holding period - Reduction (%) of the drying period
Minimum number of hours during which the sausage is held at a temperature no lower than:
Internal temperature of product Table Note 2 (minimum)
21.1°C 70°F 23.9°C 75°F 26.7°C 80°F 29.5°C 85°F 32.2°C 90°F 35.0°C 95°F 37.9°C 100°F 40.6°C 105°F 43.3°C 110°F 48.9°C 120°F
24 hrs. 4% 5% 8% 10% 15% 23% 37% 57% 90% 100% Table Note 3
48 hrs. 9% 12% 18% 25% 35% 49% 88% 100% Table Note 3 100% Table Note 3 100%
72 hrs. 14% 19% 28% 39% 55% 74% 100% Table Note 3 100% 100% 100%
96 hrs. 19% 26% 38% 53% 75% 98% 100% Table Note 3 100% 100% 100%
120 hrs. 24% 33% 48% 67% 95% 100% Table Note 3 100% 100% 100% 100%

Table Notes

Table Note 2

Internal product temperature is used for all types of sausages with the exception of dry cured fermented sausages (e.g. sausages with a pH ≤ 5.3 at the end of the fermentation period and an aw of 0.90 or less at the end of drying). In these cases room temperature or product temperature is used.

Return to table note 2  referrer

Table note 3

Trichinella will be destroyed during fermentation or smoking at the temperature and length of time indicated. Therefore, no drying room period is required for Trichinella destruction for products so treated. However, the total holding period is last at least 48 hours.

Return to table note 3  referrer

How to use Table A.1.6.2:
  1. Determine how long and at which temperature the sausage will be fermented or smoked (Note: the heat treatment takes place during the holding period).
  2. Identify the appropriate row and column for these values in the table: when the time and/or temperature values used in the preparation of the product are not listed, select the next lowest value(s) (see following example).
  3. Find the % in reduction time.
  4. To obtain the number of days by which the minimum drying period can be reduced, multiply the % in reduction value by the baseline minimum number of drying days for the type of sausage (see Table A.1.6.1) and round this value to the next lowest integer number of days.
Example:

A 7.6 cm (3 inches) diameter sausage fermented at 29°C for 60 hours.

  1. The exact temperature is not in the table; the next lowest value in the table is 26.7°C.
  2. The exact time is not in the table; the next lowest value in the table is 48 hours.
  3. The percentage of reduction found in the table with 26.7°C and 48 hours is 18%.
  4. According to Table A.1.6.1, the baseline number of minimum drying days for the type of sausage of 7.6 cm diameter, is 20 days. The number of days by which the minimum drying period can be reduced is:

    20 days × 18% = 3.6 days (round to 3 days (nearest lowest number))

    Therefore, a reduction of three days to the number of drying days is allowed; the minimum number of drying days for this type of sausages is 20 days − 3 days = 17 days.

A.1.6.3. Reduced salt content: Increase in drying room times

Sausages prepared according to the general requirements in A.1.6.1 but with a recipe using less than 3.33% of salt per weight of unstuffed sausage material excluding the weight of dry ingredients (such as salts, sugars and spices) may be permitted provided the drying time is increased according to the schedule contained in Table A.1.6.3.

Table A.1.6.3 - Increase in drying room times for reduced salt content sausages prepared according to Method # 6
Minimum % of salt in sausage Table Note 4 Increase in drying room time (%)
3.3% 1%
3.2% 4%
3.1% 7%
3.0% 10%
2.9% 13%
2.8% 16%
2.7% 19%
2.6% 22%
2.5% 25%
2.4% 28%
2.3% 31%
2.2% 34%
2.1% 37%
2.0% 40%

Table Note

Table Note 4

Calculated on the base of the weight of sausage materials excluding dry ingredients (see section A.1.6.1)

Return to table note 4  referrer

How to use Table A.1.6.3:
  1. Calculate the percentage of salt in the sausage with the formula in section A.1.6.1
  2. With Table A.1.6.3 above, find the percentage by which the drying period is to be extended.
  3. To obtain the number of days by which the drying period is to be extended, multiply the % by the baseline minimum number of drying days specified in Table A.1.6.1 for the type of sausage in question and round this value to the nearest greater integer.
Example:

A 5.0 cm (2 inches) diameter sausage with 2.0% salt requires a 40% increase in drying time according to Table A.1.6.3.

  1. According to Table A.1.6.3, an increase of 40% in the drying time is required for sausages containing 2.0% salt.
  2. Same as 1.
  3. The formula used: 40% × 16 days = 6.4 days i.e. (round to next highest integer) 7 days. (The baseline number of drying days for a 2 inch sausage (see Table A.1.6.1) is 16 days).
    Therefore an extension to the drying period of 7 days is required; the minimum number of drying days for the sausage in this example is 16 days + 7 days = 23 days.

A.1.7 Method # 7 (Dry Sausages)

Meat is ground or chopped into pieces of a maximum 0.6 cm (¼ inch) diameter or less. A minimum of 2.7% of salt per weight of sausage meat is uniformly mixed with the ground or chopped meat.

Depending on the size of the sausages, the treatment is as follows.

A.1.7.1 Sausages with a diameter of 10.5 cm (4 ⅛ inches) or less

Sausages at the time of stuffing are subjected to the following 23 hour process schedule after stuffing.

Table A.1.7.1: Process schedule for heat treated dry sausage of a diameter of 10.5 cm (4 ⅛ inches) or less
Step Minimum room temperature Minimum time (hours)
1 10.0°C / 50°F 12 hours
2 32.2°C / 90°F 1 hour
3 37.8°C / 100°F 1 hour
4 43.3°C / 110°F 1 hour
5 48.9°C / 120°F 1 hour
6 51.7°C / 125°F 7 hours

Total Time: 23 Hours

The sausages are then dried at a minimum temperature of 10°C for not less than 7 days.

A.1.7.2 Sausages with a diameter of 5.5 cm (2 ⅛ inches) or less

Alternatively, sausages with a diameter of 5.5 cm (2 ⅛ inches) or less at the time of stuffing, are to be subjected to the following 19-hour process schedule.

Table A.1.7.2: Process schedule for heat treated dry sausage of a diameter of 5.5 cm (2 ⅛ inches) or less
Step Minimum room temperature Minimum time (hours)
1 10.0°C / 50°F 12 hours
2 37.8°C / 100°F 1 hour
3 51.7°C / 125°F 6 hours

Total Time: 19 Hours

The sausages are then to be dried at a minimum temperature of 10°C for not less than 4 days.

Summary table of curing methods for sausage to ensure the destruction of Trichinella in sausage containing striated pork muscle
Method Maximum diameter of meat particles (cm) Minimum % of salt per weight of sausage material Diameter of sausage at time of stuffing (cm) Minimum curing time cure room temperature ≥3°C (days) Minimum smoking period – Time (hrs) Minimum smoking period – Initial Smokehouse temperature (°C) Minimum holding time in drying room temperature ≥7.3°C (days) Minimum time between addition of cure and release from the drying room (days)
1 1.9 3.33 < 3.5 Table Note 5 N/A N/A 15 20
1 1.9 3.33 < 8.8 N/A N/A 20 25
1 1.9 3.33 8.8 – 10.2 N/A N/A 35 40
2 1.9 3.33 < 8.8 N/A 40 ≥26.7°C 10 18
2 1.9 3.33 8.8 – 10.2 N/A 40 ≥26.7°C 25 33
3 1.9 3.33 < 8.8 6 Table Note 6 12 ≥32.3°C Table Note 7 N/A N/A
3 1.9 3.33 8.8 – 10.2 6 Table Note 6 15 ≥32.3°C Table Note 8 N/A N/A
4 0.6 2.5 < 8.5 10 Table Note 9 See Table Note 10 N/A 35 Table Note 10
5 Table Note 11 1.9 3.33 N/A N/A N/A N/A 65 N/A
6 1.9 See Table Note 12 2.5 – 15.0 Table Note 13 2 Table Note 14 See Table Note 15 See Table Note 16 N/A
7 0.6 See Table Note 17 < 10.5 N/A See Table Note 18 7 N/A
7 0.6 See Table Note 17 < 5.5 N/A See Table Note 19 4 N/A

Table Notes

Table Note 5

Sausages of the Pepperoni variety

Return to table note 5  referrer

Table note 6

This 6-day curing period includes a minimum 36-hour period, prior to stuffing, where the mixture is held at a temperature of 1.2°C or higher. Sausages may either be held at 1.5°C or more or placed in a pickle-cure of 50° (salimeter reading) or more at a temperature of 6.7°C or more for the remainder of the 6 days.

Return to table note 6  referrer

Table Note 7

During this 12-hour period, the smokehouse temperature is gradually raised (over a minimum period of 4 hours) and maintained (for a minimum of 4 additional hours) at 53.4°C or higher.

Return to table note 7  referrer

Table Note 8

During this 15-hour period, the smokehouse temperature is gradually raised (over a minimum period of 4 hours) and maintained (for a minimum of 7 additional hours) at 53.4°C or higher.

Return to table note 8  referrer

Table Note 9

This 10-day curing period takes place before stuffing; product is stored at 2.3°C or more as a compact mass of a depth not to exceed 15.2cm.

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Table note 10

A maximum of 3 hours cooking in a 29.5°C water bath and/or maximum 3 hours smoking at 26.7°C is permitted; if either option is used, the drying time is extended by a period of time equivalent to the time taken to cook and/or smoke the sausage.

Return to table note 10  referrer

Table Note 11

The coverings of these sausages may be coated with paraffin or other suitable substance.

Return to table note 11  referrer

Table Note 12

Salt content (%) is calculated on the basis of the unstuffed sausage weight, exclusive of the weight of the dry ingredients. The baseline value of salt % is 3.33%. Salt content may be reduced; see section A.1.6.3

Return to table note 12  referrer

Table Note 13

See section A.1.6.1 for specific information regarding this method.

Return to table note 13  referrer

Table Note 14

The 48 hour holding period at 1.7°C may be partly or entirely completed before the end of the drying period, if the holding period is not entirely completed before the drying period, the remainder can be completed after the end of drying, or as an extension of the drying process.

Return to table note 14  referrer

Table Note 15

Smoking of sausage is optional and may be used to lower the drying time; see section A.1.6.2

Return to table note 15  referrer

Table Note 16

This value is to be determined in accordance to the exact process used; see section A.1.6

Return to table note 16  referrer

Table note 17

This percentage is calculated on the basis of the sausage meat only (2.7%).

Return to table note 17  referrer

Table Note 18

Sausages are processed according to the method prescribed in Table A.1.7.1

Return to table note 18  referrer

Table Note 19

Sausages are processed according to the method prescribed in Table A.1.7.2

Return to table note 19  referrer

N/A Not applicable or no minimum standard specified.

A.2 Capicola (Capocollo Capacola) and Coppa

Capicola, Capocollo and Capacola are dry-cured smoked boneless pork shoulder butts.

Coppa is a dry-cured unsmoked boneless pork shoulder butt.

Boneless pork butts used for coppa or capicola (or Capocolo or Capacola) are to be dry-cured using a mixture containing a minimum 4.5 kg of salt per 100 kg of fresh meat (weight before curing). Product is cured and dried according to the schedule set out in Table A.2.

If curing materials are applied by the "churning" process, a small amount of pickle may be added. During the curing period, butts may be overhauled (for example, turned over for application of additional pickle or dry salt during the process).

In addition, capicola, capocollo and capacola are smoked at a minimum temperature of 26.7°C for a minimum period of 30 hours.

Butts are not to be treated, except for superficial washing, in any manner designed to remove salt from the meat during or after curing.

Table A.2: Minimum treatments for ensuring the destruction of Trichinella.
Type of Product Curing period at temperature not lower than 2.3°C (36°F) (days) Smoking time at temperature not lower than 26.7°C (80°F) (hours) Drying time at temperature not lower than 7.3°C (45°F) (days)
Capicola, Capocollo, Capacola 25 30 20
Coppa 18 N/A 35

A.3 Hams and pork shoulders picnics

In the curing of hams and pork shoulder picnics, one of the following methods is used to destroy Trichinella.

A.3.1. Method #1

Hams and pork shoulder picnics are laid down in salt, in a ratio of at least 4.0 kg of salt for each 100 kg of fresh meat (before curing) for a minimum of 40 days in a room maintained at a temperature not lower than 2.3°C.

Salt is to be applied in a thorough manner to the lean meat of each item. When placed in cure, product may be pumped with pickle. At least once during the curing process, products are to be overhauled (turned over for application of additional cure) and additional salt applied, if required, to thoroughly cover the lean meat of each item.

At the end of the curing period, product may be soaked up to a maximum of 15 hours in water at a temperature not to exceed 21°C (70°F). The water may be changed only once during this 15 hour period. The product is not to be treated, except for superficial washing, in any other manner designed to remove salt from the meat.

Finally, product is dried or smoked at a time and temperature specified in Table A.3.3 below.

A.3.2. Method # 2

A.3.2.1. Traditional dry curing:

Hams and shoulders should have all exposed muscle tissue covered and the hock region packed with a cure mixture containing a minimum of 70% salt (by weight of the curing mixture).

Curing consists of:

The number of days obtained using days/kg, is calculated by multiplying the value of #days/kg by the weight in kilograms of the heaviest piece of the lot (as weighed prior to the addition of cure materials).

The total curing time (between application of cure and entry into the drying room) is at least 40 days and in no case less than 4.4 days/kg of uncured ham or shoulder.

During the curing time, exposed muscle tissue stays coated with the cure mixture. After this period, the operator may remove excess cure from the product's surface either mechanically or by a water rinse of a maximum duration of 60 seconds, and allow the product to rest in order to permit salt to permeate the product's inner tissues (equalization). Soaking of hams to remove cure is not permitted.

Product is to be dried in accordance with Table A.3.3.

A.3.2.2. Bag curing:

Hams and cure mixture are wrapped together in uncoated kraft paper and hung individually. Reapplication of salt is not necessary since the wrapping keeps the cure mixture in close contact with the product.

Exposed muscle tissue is rubbed and hocks packed with a cure mixture containing at least 6 kg of salt for each 100 kg of uncured meat (weighed before the addition of curing material). Any remaining cure mixture is used in wrapping the product in the paper bag.

Product remains wrapped during a minimum curing period of at least 40 days but not less than 4.4 days/kg of uncured ham or shoulder (which ever period is longest) at a room temperature between 1.7°C and 7.3°C. It may be unwrapped during the drying period.

The number of days obtained using days/kg, is calculated by multiplying the value of #days/kg by the weight in kilograms of the heaviest piece of the lot (as weighed prior to the addition of cure materials).

Product is to be dried in accordance with Table A.3.3.

A.3.3 Method # 3

Hams and shoulders are cured with a cure mixture containing a minimum of 71.5% salt by weight. The operator may substitute potassium chloride (KCl) for up to half of the required salt on an equal weight basis.

Cure is applied at a minimum rate of 5.72 kg of cure for each 100 kg of fresh meat (weighed before addition of the curing materials). The hock region is to be packed and all exposed muscle tissue covered. The cure is applied in either three or four approximately equal amounts (three or four overhauls) at separate times during the first 14 days of curing.

The product is kept in contact with the cure mixture at a minimum temperature of 1.7°C for a minimum period of 4.4 days/kg of uncured product but for at least 30 days, whichever period is longest.

The number of days obtained using days/kg, is calculated by multiplying the value of #days/kg by the weight in kilograms of the heaviest piece of the lot (as weighed prior to the addition of cure materials).

At the end of the cure contact period, excess cure mixture may be removed either by rinsing for a maximum of 60 seconds with water or by mechanically removing the excess from the product's surface. Soaking is not allowed.

After the cure contact period has ended and the excess cure has been removed, an additional period of a minimum 2.2 days/kg of uncured product but at least 14 days (whichever period is longest) is provided to allow the cure to permeate the deeper muscle masses. Additional cure contact days may be substituted for an equal number of equalization days.

Drying cannot begin until the end of the equalization period. Drying is to be performed according to one of the methods described in Table A.3.3.

Table A.3.3: Minimum drying time/temperature combinations to ensure the destruction of Trichinella in dry cured hams
Minimum drying temperature (°F) Minimum drying temperature (°C) Minimum days at drying temperature Fractional period/ drying day
≥130 ≥54.4 1.5 0.67
≥125 ≥51.7 2 0.50
≥120 ≥48.9 3 0.33
≥115 ≥46.1 4 0.25
≥110 ≥43.3 5 0.20
≥105 ≥40.6 6 0.17
≥100 ≥37.8 7 0.14
≥95 ≥35.0 9 0.11
≥90 ≥32.2 11 0.091
≥85 ≥29.4 18 0.056
≥80 ≥26.7 25 0.040
≥75 ≥23.9 35 0.029

How to use Table A.3.3:

Interpolation of these times or temperatures is not acceptable.

A.4 Boneless pork loins and loin ends

Loins are cured for a minimum period of 25 days at a temperature not lower than of 2.3°C using one of the following methods.

Loins may be soaked in maximum 21°C temperature water for a maximum duration of one hour, or washed under a spray. Product is not to be subjected, during or after curing, to any other treatment designed to remove salt.

Loins are smoked for a minimum of 12 hours. The smokehouse temperature is maintained above a minimum temperature of 37.8°C during the entire smoking process. In addition, within the 12 hours smoking period, the smokehouse temperature is maintained at a minimum temperature of 51.7°C for at least four consecutive hours.

Smoked product is then to be held in a drying room maintained at a temperature of not less than 7.3°C for a minimum period of 12 days.

B. Heating

All parts of the pork muscle tissue are heated according to one of the time/temperature combinations listed in Table B..

Table B. - Thermal treatments to ensure the destruction of Trichinella in pork products
Minimal internal temperature (°C) Minimum time Table Note 20
49 21 hrs.
50 9.5 hrs.
52 4.5 hrs.
53 2.0 hrs.
54 1.0 hr.
55 30 min.
56 15 min.
57 6 min.
58 3 min.
59 2 min.
60 1 min. Table Note 21
62 1 min. Table Note 21
63 Instant Table Note 21

Table Notes

Table Note 20

The time to raise internal product temperature from 15°C to 49°C does not to exceed 2 hours unless the product is cured or fermented.

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Table note 21

Time, when in combination with internal product temperatures of 59°C to 62°C, does not need to be monitored if the product's minimum thickness exceeds 5.1 cm and refrigeration of the product does not begin within 5 minutes of attaining 59°C.

Return to table note 21  referrer

C. Freezing

There are five freezing methods described below. Consider the following highlights of these various methods for destroying Trichinella.

C.1.1 Freezing Method #1:

After preparatory chilling to a temperature of 4°C or less, pork striated muscle or products containing pork striated muscle tissue are kept frozen at the indicated temperature for an uninterrupted length of time equal or longer to the one specified in the following table.

Table C.1.1: Freezing Method #1 to ensure the destruction of Trichinella
(Temperature −25°C)
Group Time
Group 1
pork products with maximum thickness of 25 cm
10 days
Group 2
pork products with thickness between 25 - 50 cm
20 days

Insulating packaging material is removed prior to the commencement of the freezing process. Boxes are stacked in such a way as to permit air circulation and to permit product to reach the freezing room temperature as quickly as possible (spacers required and no shrink wrap).

Freezing time calculation begins only from the moment that the freezer's temperature reaches the specified value. In cases where the freezer temperature exceeds the specified maximum temperature indicated in the freezing schedule, the operator either uses a different time-temperature schedule which allows for the higher temperature or restarts the counting of the number of uninterrupted freezing days from the moment that the freezer temperature returns below the specified maximum.

C.1.2 Freezing Method # 2:

After preparatory chilling to a temperature of 4°C or less, pork muscle or products containing pork muscle tissue are kept frozen at the indicated temperature for an uninterrupted length of time equal or longer to the one specified in Table C.1.2.

Insulating packaging material is removed prior to the commencement of the freezing process. Boxes are stacked in such a way as to permit air circulation and to permit product to reach the freezing room temperature as quickly as possible (spacers required and no shrink wrap).

Freezing time calculation begins only from the moment that the freezer's temperature reaches the specified value. In cases where the freezer temperature exceeds the specified maximum temperature indicated in the freezing schedule, the operator either uses a different time-temperature schedule which allows for the higher temperature or restarts the counting of the number of uninterrupted freezing days from the moment that the freezer temperature returns below the specified maximum.

Table C.1.2: Freezing Method # 2 to ensure destruction of Trichinella
Freezer temperature (°C) Min. # of days (uninterrupted)
Group 1
Min. # of days (uninterrupted)
Group 2
−15 20 30
−23 10
−25 20
−29 6 12

Group 1: 15 cm thickness or less

Group 2: 15 to 50 cm thickness

C.1.3 Freezing Method # 3:

In lieu of the methods prescribed in Freezing Method # 1 and Freezing Method #2 above, products containing pork striated muscle may be treated by means of commercial freeze drying or controlled freezing.

When using this method # 3, there is no obligation to use spacers and the use of shrink wrap around pallets is considered acceptable.

Product brought in already frozen is treated in accordance with one of the time/product internal temperature combinations specified in Table C.1.3. For each lot, the internal temperature is to be monitored by a thermocouple placed in the centre of the thickest piece of meat and in the warmest location of the freezer (not close to cooling equipment). The temperature is measured with properly calibrated thermoelectric instruments (recording thermometers) and continuously recorded. The charts include pertinent information, including the lot number, its description, the number of boxes, date in and date out.

Table C.1.3 Freezing Method # 3 to ensure destruction of Trichinella
Product internal temperature (°C) Minimum time (hours)
−18.00 106
−21.00 82
−23.50 63
−26.00 48
−29.00 35
−32.00 22
−35.00 8
−37.00 ½

Temperature, when measured in degrees Celsius, is measured to the next lowest tenth of a degree Celsius or, in the case of temperature measuring devices unable to attain such a degree of accuracy, to the next lowest degree Celsius. For example, if a thermometer is not accurate enough to read −23.5°C, the meat is frozen to −24°C.

C.1.4 Freezing Method # 4:

For freezing methods #1 and #2, the control of the freezing temperature is accomplished by monitoring the freezer's ambient temperature. For freezing method # 3, the same control is exerted through the use of a thermocouple in the centre of the warmest piece of meat.

A fourth method has been found acceptable. This method is based on both types of controls to ensure the destruction of trichina.

When using this method # 4, there is no obligation to use spacers and the use of shrink wrap around pallets is acceptable.

This method is done in two steps.

Step 1:

The purpose of this first step is to ensure that all products in the lot to be treated have attained a temperature equilibrium with the freezer temperature. For each lot, the internal temperature is to be monitored by a thermocouple placed in the centre of the thickest piece of meat and in the warmest location of the freezer (not close to cooling equipment). As soon as the product is brought into the freezer, a thermocouple is placed at the centre of the warmest box of the lot. This box is then placed at the centre of the largest pallet. The temperature is then to be measured with properly calibrated thermoelectric instruments (recording thermometers) and continuously recorded until product temperature at the centre of this box is the same as the freezer's ambient temperature.

Step 2:

At this time, the thermocouple may be removed. The freezing time calculation may begin. The treated products are kept frozen at the indicated temperature for an uninterrupted length of time equal or longer to the one specified in Table C.1.1 or C.1.2.

For each lot treated, the operator keeps the charts of the two steps to clearly demonstrate the control that is exerted. Records for the two steps are kept on file for each lot. The charts include all pertinent information, including the lot number, its description, the number of boxes, date in, date out and the freezing method used. The official log book should be completed.

C.1.5 Freezing Method # 5

This method has two steps and applies only to big cuts of meat in bulk containers, e.g. a ham with bone (refer to Table C.1.3).

Step 1:

The first step consists in ensuring that all refrigerated products that will be put in bulk containers will reach a temperature of −18°C or lower. From the outset of the freezing process, core temperature is monitored for each lot to be treated using a thermocouple inserted in the middle of the biggest cut of meat located in the warmest part of the freezer (not close to a refrigeration unit). Temperature is recorded on a continuous basis using properly calibrated thermoelectric instruments (recording thermometers).

Step 2:

Treated products are kept at the prescribed temperature without interruption for the amount of time specified in Table C.1.3.

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