Chapter 7: Smoked Fish and Fishery Products

• Potential Food Safety Hazard
• Control Measures
• FDA Guidelines
• AFDO Guidelines
• NMFS Guidelines
• State Guidelines
• Alaska Smoked Fish regulations
• Michigan Smoked Fish Regulations
• Minnesota Smoked Fish Regulations
• New York: Smoked Fish Air Packed
• New York: Vacuum Packaged or Modified Packaged
• New York: VP/MAP Smoked Fish Processing Guidelines
• Process Establishment
• Critical Aspects of Processes
• Analytical Procedures
• Smoking Processes
• References

When C. botulinum grows it can produce a potent toxin, which can cause death by preventing breathing. It is one of the most poisonous naturally occurring substances known. The toxin can be destroyed by heat (e.g. boiling for 10 minutes), but processors cannot rely on this as a means of control.

There are two major groups of C. botulinum, the proteolytic group (i.e. those that break down proteins) and the nonproteolytic group (i.e. those that do not break down proteins). The proteolytic group includes C. botulinum type A and some of types B and F. The nonproteolytic group includes C. botulinum type E and some of types B and F.

The vegetative cells of all types are easily killed by heat. C. botulinum is able to produce spores. In this state the pathogen is very resistant to heat. The spores of the proteolytic group are much more resistant to heat than are those of the nonproteolytic group. Table A-4  provides guidance about the conditions under which the spores of the most heat resistant form of nonproteolytic C. botulinum, type B, are killed. However, there are some indications that substances that may be naturally present in some products, such as lysozyme, may enable nonproteolytic C. botulinum to more easily recover after heat damage, resulting in the need for a considerably more aggressive process to ensure destruction.

Temperature abuse occurs when product is exposed to temperatures favorable for C. botulinum growth for sufficient time to result in toxin formation. Table A-1 provides guidance about the conditions under which C. botulinum and other pathogens are able to grow.

Packaging conditions that reduce the amount of oxygen present in the package (e.g. vacuum packaging) extend the shelf life of product by inhibiting the growth of aerobic spoilage bacteria. The safety concern with these products is the increased potential for the formation of C. botulinum toxin before spoilage makes the product unacceptable to consumers.

C. botulinum forms toxin more rapidly at higher temperatures than at lower temperatures. The minimum temperature for growth and toxin formation by C. botulinum type E and nonproteolytic types B and F is 38°F (3.3°C). For type A and proteolytic types B and F, the minimum temperature for growth is 50°F (10°C). As the shelf life of refrigerated foods is increased, more time is available for C. botulinum growth and toxin formation. As storage temperatures increase, the time required for toxin formation is significantly shortened. Processors should expect that at some point during storage, distribution, display or consumer handling of refrigerated foods, proper refrigeration temperatures will not be maintained (especially for the nonproteolytic group). Surveys of retail display cases indicate that temperatures of 45-50°F (7-10°C) are not uncommon. Surveys of home refrigerators indicate that temperatures can exceed 50°F (10°C).

In reduced oxygen packaged products in which the spores of nonproteolytic C. botulinum are inhibited or destroyed (e.g., smoked fish, pasteurized crabmeat, pasteurized surimi), normal refrigeration temperatures of 40°F (4.4°C) are appropriate because they will limit the growth of proteolytic C. botulinum and other pathogens that may be present. Even in products where nonproteolytic C. botulinum is the target organism for the pasteurization process and vegetative pathogens, such as Listeria monocytogenes, are not likely to be present (e.g. pasteurized crabmeat, pasteurized surimi), a storage temperature of 40°F (4.4°C) is still appropriate because of the potential survival through the pasteurization process and recovery of spores of nonproteolytic C. botulinum aided by naturally occurring substances, such as lysozyme. In this case refrigeration serves as a prudent second barrier.

In reduced oxygen packaged products in which refrigeration is the sole barrier to outgrowth of nonproteolytic C. botulinum and the spores have not been destroyed (e.g. vacuum packaged raw fish, unpasteurized crayfish meat), the temperature must be maintained at 38°F (3.3°C) or below from packing to consumption. Ordinarily processors can ensure that temperatures are maintained at or below 38°F (3.3°C) while the product is in their control. However, current distribution channels do not ensure the maintenance of these temperatures after the product leaves their control. The use of time temperature integrators on each consumer package may be an appropriate means of enabling temperature control throughout distribution. Alternatively, products of this type may be safely marketed frozen, with appropriate labeling. For some products, control of C. botulinum can be achieved by breaking the vacuum seal before the product leaves the processor's control (FDA, 2001).

Sources of C. botulinum

Reduced oxygen packaging

There are a number of conditions that can result in the creation of a reduced oxygen packaging environment. They include:

• Vacuum packaging or modified or controlled atmosphere packaging. These packaging methods directly reduce the amount of oxygen in the package;

• Packaging in hermetically sealed containers (e.g. double seamed cans, glass jars with sealed lids, heat sealed plastic containers), or packing in deep containers from which the air is expressed (e.g. caviar in large containers), or packing in oil. These and similar processing/packaging techniques prevent the entry of oxygen into the container. Any oxygen present at the time of packaging may be rapidly depleted by the activity of spoilage bacteria, resulting in the formation of a reduced oxygen environment.

Packaging that provides an oxygen transmission rate of 10,000 cc/m²/24hrs (e.g. 1.5 mil polyethylene) can be regarded as an oxygen-permeable packaging material for fishery products. This can be compared to an oxygen-impermeable package which might have an oxygen transmission rate as low as or lower than 100 cc/m²/24hr (e.g. 2 mil polyester). An oxygen permeable package should provide sufficient exchange of oxygen to allow aerobic spoilage organisms to grow and spoil the product before toxin is produced under moderate abuse temperatures. However, use of an oxygen permeable package will not compensate for the restriction to oxygen exchange created by practices such as packing in oil or in deep containers from which the air is expressed (FDA, 2001).

• Controlling the amount of salt or preservatives, such as sodium nitrite, in the finished product, in combination with other barriers, such as heat damage and competitive bacteria, sufficient to prevent the growth of C. botulinum type E and nonproteolytic types B and F;
• Managing the amount of time that food is exposed to temperatures that are favorable for C. botulinum growth and toxin formation during processing and storage ; and
• Controlling the growth of C. botulinum type A and proteolytic types B and F in the finished product with refrigerated storage.

In hot-smoked products, heat damage to the spores of C. botulinum type E and nonproteolytic types B and F also helps prevent toxin formation. In these products control of the heating process is critical to the safety of the finished product. It is important to note, however, that this same heating process also reduces the numbers of naturally occurring spoilage organisms. The spoilage organisms would otherwise have competed with, and inhibited the growth of, C. botulinum.

In cold-smoked fish, it is important that the product does not receive so much heat that the number of spoilage organisms are significantly reduced. This is true because spoilage organisms must be present to inhibit the growth and toxin formation of C. botulinum type E and nonproteolytic types B and F. This inhibition is important in cold-smoked fish because the heat applied during this process is not adequate to weaken the C. botulinum spores. Control of the temperature during the cold-smoking process is, therefore, critical to the safety of the finished product.

The interplay of these inhibitory effects (salt, temperature, smoke, and nitrite) is complex. Control of the brining or dry salting process is clearly critical to ensure that there is sufficient salt in the finished product. However, preventing C. botulinum type E (and nonproteolytic types B and F) toxin production is made even more complex by the fact that adequate salt levels are not usually achieved during brining. Proper drying is also critical in order to achieve the finished product water phase salt level (the concentration of salt in the water portion of the fish flesh) needed to inhibit the growth and toxin formation of C. botulinum.

Processors should ordinarily restrict brining, dry salting, and smoking loads to single species and to fish of approximately uniform size. This minimizes the complexity of controlling the operation.

Salt levels alone in some salted products may be adequate to prevent toxin formation by C. botulinum type A and proteolytic types B and F. However, even the combination of inhibitory effects that are present in smoked and smoke-flavored fish are not adequate to prevent the growth of type A and proteolytic types B and F. Strict refrigeration control must be maintained to prevent the growth of C. botulinum type A and proteolytic types B and F in these products (FDA, 1998).

Cold-Smoked Fish (Oxygen Permeable Packaging)

• No guidelines; treat as fresh fish

Cold-Smoked Fish (Reduced Oxygen Packaging)

• The smoker temperature must not exceed 32.2ºC (90°F) (FDA, 2001).

Hot-Smoked Fish (Oxygen Permeable Packaging)

• No guidelines; treat as cooked ready-to-eat fish

Hot-Smoked Fish (Reduced Oxygen Packaging

• The internal temperature of the fish must be maintained at or above 62.8ºC (145°F) throughout the fish for at least 30 min (FDA, 2001).
• Not less than 3.5% water phase salt in the loin muscle, or, where permitted, the combination of 3.0% water phase salt in the loin muscle and 100-200 ppm nitrite (FDA, 2001; 21CFR172.175; 21CFR172.177).
• The product must not be exposed to temperatures above 10ºC (50ºF) for more than 12 h nor to temperatures above 21.1ºC (70ºF) for more than 4 h, excluding time above 60ºC (140°F) (FDA, 2001).
• The product must not be exposed to storage temperatures above 10ºC (50ºF), which may be assured by:
  • A maximum cooler temperature of 10ºC (50ºF); and/or
  • The presence of sufficient cooling media (e.g., adequate ice to completely surround the product) (FDA, 2001).
• The product must not be exposed during transportation to temperatures above 10ºC (50ºF), which may be assured by:
  • A maximum refrigerated container temperature of 10ºC (50ºF) throughout transit; or
  • The presence of sufficient cooling media (e.g., adequate ice to completely surround the product) upon receipt (FDA, 2001).

Plants and grounds

1. The following processes must be carried out in separate rooms or in a segregated fashion so as to eliminate contamination:
1. Receiving or shipping
2. Storage of raw fish
3. Presmoking operations such as thawing, dressing, and brining
4. Drying and smoking
5. Cooling and packing
6. Storage of final product
2. The product must be so processed as to prevent contamination by exposure to areas, utensils, or equipment involved in earlier processing steps, refuse, or other objectionable areas.

Sanitary operations

1. Before beginning the day's operations, all utensils and food contact surfaces of equipment to be used for the day's operations must be rinsed and sanitized to protect against the introduction of microorganisms into the fish or other ingredients. All utensils and food contact surfaces of equipment must be cleaned and sanitized after any interruption during which the food contact surfaces may have become contaminated.
2. Equipment and utensils used in the handling of raw or frozen fish and fish portions must not be used in the handling, transport, or packaging of product after it has entered the smoking chamber or used in the handling of finished product.

Sanitary facilities and controls

1. Readily understandable signs directing employees handling unprotected food, unprotected food packaging materials, or food contact surfaces to wash and sanitize their hands before they start work, after each absence from post of duty, and when their hands have become soiled or contaminated, should be conspicuously posted in the processing room(s), finished product packing room(s), and in all other areas where conditions require.
2. Handwashing facilities shall be conveniently located to permit use by all employees in fish preparation and processing areas. Handwash facilities shall be accessible to these employees at all times.
3. Handwash facilities shall be located in or immediately adjacent to toilet rooms or their vestibules.

Equipment and utensils

1. All plant equipment and utensils must be designed and of such material and workmanship as to be adequately cleanable, nonabsorbant, corrosion resistant, and they must be properly maintained. The design, construction, and use of equipment and utensils must preclude the adulteration of food with lubricants, fuel, metal fragments, wood fragments, contaminated water, or any other contaminants. All equipment must be installed and maintained as to facilitate the cleaning and sanitizing of the equipment and of all adjacent spaces. Food contact surfaces must be corrosion resistant when in contact with food. They must be made of nontoxic materials and designed to withstand the environment of their intended purpose (i.e., refrigerated storage, brining tank) and the action of the food, and cleaning and sanitizing agents. Food contact surfaces must be maintained to protect the food from being contaminated by any source, including unlawful indirect food additives.
2. Containers used to convey, brine, or store fish must not be nested while they contain fish or otherwise handled during processing or storage in a manner conducive to direct or indirect contamination of their contents.
3. Cleaning and sanitizing of utensils and portable equipment must be conducted in an area set aside for these purposes or in a segregated fashion so as to prevent contamination of food.
4. Each freezer and cold storage compartment used to store and hold food must be fitted with a thermometer or temperature recording device so installed as to show the temperature accurately within the compartment.
5. Instruments and controls used for measuring, regulating, or recording temperatures must be accurate and maintained on a regular schedule, and adequate in number for their designated uses.
6. Compressed air or other gases used to clean food contact surfaces or equipment must be treated in such a way that food is not contaminated with unlawful indirect food additives.
7. Each smoking chamber must be equipped with a temperature monitoring device so installed as to indicate accurately at all times the temperature of the air and of the fish within the smoking chamber, where required.
8. Thermometers or other temperature measuring devices must have an accuracy of ± 2ºF (1.1ºC) and the graduations must not exceed 2ºF (1.1ºC) within a range of 10ºF (5.5ºC) of the processing temperature. The accuracy of these devices must be maintained.
9. Equipment and utensils must be marked in some may to ensure that equipment and utensils used to handle raw fish are not used to handle product which has entered the smoking chamber or used in the handling of finished product.

Raw materials

1. Fresh fish received shall be inspected and adequately washed before processing. Only sound, wholesome fish free from adulteration and organoleptically detectable spoilage shall be processed.
2. Frozen fish received shall be adequately inspected, and only clean wholesome fish shall be processed.
3. Fresh fish, except those to be immediately processed, shall be iced or otherwise refrigerated to an internal temperature of 38ºF (3.3ºC) or below upon receipt and shall be maintained at that temperature until the fish are to be processed.
4. All fish received in a frozen state shall be either thawed promptly and processed, or stored at a temperature that will maintain it in a frozen state.
5. The defrosting of frozen fish shall be conducted in a sanitary manner and by such methods that the wholesomeness of the fish is not adversely affected. Frozen fish shall be defrosted:
1. In air so the temperature in any part of the fish does not exceed 45ºF (7.2ºC); or
2. In a continuous water-overflow thaw tank or spray system in such a manner that the temperature of the water does not exceed 60ºF (15.5ºC) and the internal temperature in any of the fish does not exceed 45ºF (7.2ºC); or
3. In a microwave tunnel in such a manner that the internal temperature in any of the fish does not exceed 45ºF (7.2ºC).
6. After thawing, fish shall be washed thoroughly with a vigorous potable water spray or a continuous water-flow system. When thawing and brining occur concurrently, the fish shall be washed in this same fashion following the thawing or brining.
7. All fish shall be free of viscera prior to processing, except:
1. Small species of fish, such as anchovies and herring sprats, provided they are processed in a safe fashion and will contain a water phase salt level of at least 10%, a water activity below 0.85, or a pH of 4.6 or less; and
2. Fermented fish, provided they are processed in a safe fashion and will contain a water phase salt level of at least 17%.
8. The evisceration of fish shall be conducted in an area that is segregated or separate from other processing operations. The evisceration shall be performed with minimal disturbance of the intestinal tract contents. The fish, including the body cavity, shall be washed thoroughly with a vigorous spray or a continuous water flow system following evisceration.

Operations and controls for processed fish

1. All operations involving the receiving, holding, processing, and packaging of processed fish shall be conducted utilizing clean and sanitary methods and shall be conducted as rapidly as practicable and at temperatures that will not cause any material increase in bacterial or other microscopic content or any deterioration or contamination of such processed fish.
2. All processed fish except smoked fish processed pursuant to the following sections shall be processed pursuant to a scheduled process established by a competent processing authority. A copy of said scheduled process which is utilized shall be available for examination in each processing establishment. The scheduled process must also be filed with the appropriate regulatory authority prior to the commencement of processing. Each scheduled process shall identify the name and address of the competent processing authority by whom it was established. The scheduled process shall include processing methods, procedures, and controls for each product, as well as packaging and labeling requirements. Whenever a deviation in a scheduled process occurs as discovered by records, processors check, or otherwise, the processors shall destroy all product affected by said deviation or hold it for a determination as to whether it is adulterated within the meaning of the Federal Food, Drug, and Cosmetic Act.
3. Mechanical manufacturing steps such as washing, cutting, sorting and inspecting, cooling, and drying must be performed so as to protect food against contamination including that which may drip, drain, or be drawn into the food. Protection must be provided by cleaning and sanitizing all food contact surfaces, and by using time and temperature controls at and between each manufacturing step.
4. All processed fish shall be distributed and sold at temperatures that do not exceed 38ºF (3.3ºC), except that:
1. Processed fish that have a water phase salt level of at least 17% shall not require refrigerated storage; and
2. Processed fish which contain a water phase salt level of at least 10% or a pH of 4.6 or below may be distributed or sold at refrigerated temperatures that do not exceed 45ºF (7.2ºC).
5. The vacuum packaging or modified atmosphere packaging of processed fish shall be conducted only within the facilities of the manufacturer.
6. Processed fish to be vacuum packaged or modified atmosphere packaged shall be chemically analyzed for water phase salt, and for nitrite and other additives when used, with sufficient frequency to ensure conformance with finished product specification requirements.

Brining or dry-salting

1. Brining must be carried out so that the temperature of the brine does not exceed 60ºF (15.5ºC) at the start of brining. If the brining time exceeds 4 h, the brining must take place in a refrigerated area at 38ºF 3.3ºC) or lower.
2. For dry salting, the fish must be returned to a refrigerated area of 38ºF (3.3ºC) or lower immediately after the application of the salt.
3. Different species of fish must not be mixed in the same brining tank.
4. Brines may not be reused unless there is an adequate process available to return the brine to an acceptable microbiological level.
5. Fish must be rinsed with freshwater after brining.

Heating, cooking, or smoking operations

1. Fish must be arranged without overcrowding or touching each other within the smokehouse oven or chamber to allow for uniform smoke absorption, heat exposure, and dehydration. Fish smoked in the same batch should be of relatively uniform size and weight.
2. Liquid smoke, generated smoke, or a combination of liquid smoke and generated smoke must be applied to all surfaces of the product. Liquid smoke can be applied to the product before, at the beginning, or during the process. Generated smoke is applied to the fish during the first half of the process. If a combination of liquid smoke and generated smoke is used, the procedures for liquid smoke must be followed and the generated smoke can be applied at any stage of the process.

Hot process smoked fish

1. Hot process smoked fish shall be produced by a controlled process that utilizes a monitoring system such as calibrated probes or recording thermometers to ensure that all products reach the required temperature. The temperature readings shall be obtained by inserting an accurate temperature indicating device into the thickest flesh portion of three or more of the largest fish in the smokehouse compartment. The coldest reading thus obtained shall be recorded in a fish smoking record as being the internal temperature of fish being smoked. The internal temperature of fish being smoked shall be obtained and recorded with the time taken at least three times during the operation of heating each load or batch of fish to assure that the required heat treatment has been accomplished. Each batch of smoked fish shall be identified as to the specific oven load, product temperature obtained, and data processed.
2. For hot process smoked fish to be air packaged, a controlled process must be used to heat fish to a continuous temperature of a least 145ºF (62.8ºC) throughout each fish for a minimum of 30 min for fish brined to contain not less than 2.5% water phase salt in the loin muscle of the finished product.
3. For hot process smoked fish to be vacuum or modified atmosphere packaged, a controlled process must be used to heat fish to a continuous temperature of at least 145ºF (62.8ºC) throughout each fish for a minimum of 30 min for fish brined to contain not less than 3.5% water phase salt in the loin muscle of the finished product or the combination of 3.0% water phase salt in the loin muscle of the finished product and not less than 100 ppm nor more than 200 ppm sodium nitrite.

Cold process smoked fish

1. Cold process smoked fish shall be produced by a controlled process that utilizes a temperature monitoring system positioned within the smoking chamber to assure that all products do not exceed process temperatures in accordance with one of the following methods:
1. The temperature in the smoking chamber does not exceed 90ºF (32.2ºC) during a drying and smoking period that does not exceed 20 h; or
2. The temperature in the smoking chamber does not exceed 50ºF (10.0ºC) during a drying and smoking period that does not exceed 24 h; or
3. The temperature in the smoking chamber does not exceed 120ºF (48.9ºC) during a drying and smoking period that does not exceed 6 h for cold process smoked sablefish.
2. For cold process smoked fish to be air packaged, only fish that have been brined to contain not less than 2.5% water phase salt in the loin muscle of the finished product may be used.
3. For cold process smoked fish to be vacuum or modified atmosphere packaged, only fish that have been brined to contain not less than 3.5% water phase salt in the loin muscle of the finished product or a combination of 3.0% water phase salt in the loin muscle of the finished product and not less than 100 ppm nor more than 200 ppm sodium nitrite may be used.

Cooling

Packaging and labeling of processed fish

1. The finished product shall be stored and handled in a segregated area apart from unprocessed fish and equipment used for unprocessed fish.
2. Shipping containers, retail packages, and shipping records relating to processed fish shall indicate, by appropriate labeling, the perishable nature of the product. Frozen product shall clearly indicate that the product shall remain frozen until thawed at refrigerated temperatures and shall not be refrozen. Refrigerated product shall clearly and conspicuously state "Keep Refrigerated at 38ºF (3.3ºC) or Below."
3. Each container of processed fish shall be marked with an identifying code which shall be permanently visible to the naked eye. Where the container does not permit the code to be embossed or inked, the label may be legibly perforated or otherwise marked, provided that in all instances the label shall be securely affixed to the product container. The required identification shall identify in code –the establishment where packed, the product contained therein, the year packed, the day packed, and the period during which packed. The packing period code shall be changed with sufficient frequency to enable ready identification of lots during their sale and distribution.

Inspection and certification of vacuum packaged hot-processed smoked or hot-processed smoke-flavored salmon

1. The processing facility must be in compliance with the requirements of 50 CFR Part 260.
2. Defrosting of eviscerated frozen fish shall be carried out in:
1. Air at 45° F (7.2° C) or below until completely thawed and the internal temperature of any part of the fish does not exceed 45° F (7.2° C).
2. A continuous water flow tank or spray system until thawed. Salmon shall not be mixed with other species during thawing. Fish shall not remain in the tank for over 4 h after they are completely defrosted and the temperature in any part of the fish shall not exceed 60° F (15.6° C) during this period. If longer delays and encountered, the fish shall be returned to temperatures of 38° F (3.3° C) or below until brined.
3. Both fresh and thawed fish shall be washed thoroughly with a vigorous chlorinated water spray or in a continuous water flow system prior to brining. (Chlorine concentration in water shall not exceed 50 ppm available chlorine).
4. All fish shall be dry-salted at a temperature not to exceed 38° F (3.3° C) throughout the fish, or if brined, the salmon shall not be mixed with other species of fish in the same tank and shall be brined in such a manner that the temperature of the fish and brine:
1. Does not exceed 60° F (15.6° C) at the start of the brining, and
2. If the brine time exceeds 4 h, the brining shall take place in a refrigerated room of 42° F (5.6° C) or lower. The product may not be held above 38° F (3.3° C) for more than 48 h.
3. Brines may not be reused unless there is an adequate process (e.g., ultrafiltration) to return the brine to an acceptable microbiological level.
[Note: Brine tanks that have been used to brine other species of fish shall be cleaned and sanitized before being used to brine salmon]
5. Hot-process smoked or hot-process smoke-flavored salmon shall be brined in such a manner that the final sodium nitrite content of the loin muscle of the finished product shall be no less than 100 ppm and no more than 200 ppm (parts per million) after processing. These same products shall contain not less than the minimum concentrations of one of the following combinations of water phase salt (w.p. NaCl) and sodium nitrite in the deepest part of the loin:

% w.p. NaCl	ppm sodium nitrite
3.5	100
3.4	120
3.3	140
3.2	160
3.1	180

6. Hot-process smoked or hot-process smoke-flavored salmon shall be heated by a controlled heat process that provides a monitoring system (e.g., calibrated probes or dial thermometers) positioned in as many strategic locations in the oven as necessary to assure that all products reach the minimum internal temperature.

[Note: The temperature monitoring device shall be tested for accuracy against a known standard thermometer upon installation and at least once a year thereafter, or more frequently if necessary, to ensure their accuracy. Graduations on the temperature monitoring device shall not exceed 2° F (1.1° C) within a range of 10° F (5.6° C) of the processing temperature.]

Each fish or fish portion shall be heated to an internal temperature of 150° F (65.6° C) or higher and maintained at 150° F (65.6° C) for 30 min or longer.

7. Liquid smoke or generated smoke or a combination of liquid smoke and generated smoke shall be applied to the entire product. If only liquid smoke is used in the process it can be applied to the product prior to, at the beginning of, or during the process. Liquid smoke added during the process shall be applied before the internal temperature of the product exceeds 125° F (51.7° C). The liquid smoke shall be prepared by the aqueous process (e.g., U.S. Patent 3,106,473) and have a minimum of the following major constituents in its compositions: 1) 10% titratable acidity; 2) 9 mg phenol/g; 3) 12 g carbonyls/100 ml, and be used at concentrations of 50% or greater.

When only generated smoke is used in the process, dense smoke shall be applied to the fish for at least 90 min at the beginning of the process. If a drying cycle is used in the smoking process, the air temperature surrounding the product shall not exceed 110° F (43.3° C) and the time period shall not exceed 60 min at temperatures between 60° F (15.6° C) and 110° F (43.3° C) before the application of smoke. If lower temperatures (60° F [15.6° C] or below) are used, this time period shall not exceed 6 h. Generated smoke shall be produced from burning hardwood. If a combination of liquid smoke and generated smoke are used, the procedures for liquid smoke shall be followed and the generated smoke can be applied at any stage of the process.

8. The finished product shall be cooled to a temperature of 50° F (10° C) or below within 5 h after cooking and further cooled to a temperature of 38° F (3.3° C) or below within 12 h after cooking. The finished product shall be maintained at 38° F (3.3° C) or lower during all subsequent storage and distribution.
9. Primary packages and master cartons shall be clearly marked with a statement to maintain the product below 38° F (3.3° C). If fish are frozen, they shall be clearly labeled to thaw at refrigerated temperatures and that the thawed product must subsequently be stored below 38° F (3.3° C).
10. The finished product shall be analyzed chemically with sufficient frequency to assure that the required water-phase salt and sodium nitrite is obtained and that other chemical additives are present at authorized levels. To reduce the possibility of post processing contamination with food poisoning bacteria, the product shall be vacuum-packaged only within the facility in which it was processed.
11. Permanently legible code marks shall be placed on the outer layer of every finished product package and master carton. Such marks shall identify at least the plant where packed and the date of packing. Records shall be maintained at the processing facility for a minimum of 6 months from the date of processing as to provide positive identification (1) of the process procedures (including process/product time, temperature, sodium nitrite and water-phase salt levels) used for the manufacture of hot-process smoked and hot-process smoke-flavored fish and (2) of the distribution of the finished product (NMFS, 1984).

• Section 310. Processing Requirements for Smoked or Smoke-Flavored Seafood Product
• Section 315. Native-Style Smoked or Smoke-Flavored Dried Salmon
• Section 320. Finished Product Handling

All processed fish shall be produced pursuant to a scheduled process established by a competent processing authority. A copy of said scheduled process shall be available for examination in each fish processing establishment. Each scheduled process shall identify the name and address of the competent processing authority by whom it was established. The scheduled process shall include processing methods, procedures and controls for each product, as well as packaging and labeling requirements. Whenever a deviation in a scheduled process occurs, as disclosed by records, processor check or otherwise, the processor shall destroy all product affected by said deviation or hold it for a determination as to whether it is adulterated within the meaning of Section 200 of the Agriculture and Markets Law:

Unless otherwise provided by a scheduled process, the following additional requirements shall apply to vacuum packaged or modified atmosphere packaged smoked fish.

1. Brining of fish for smoking shall be carried out so that the temperature of the brine does not exceed 60 degrees Fahrenheit at the start of brining. If the brining time exceeds 4 hours, the brining shall take place in a refrigerated area of 38 degrees Fahrenheit or lower. For dry salting, the fish shall be returned to a refrigerated area of 38 degrees Fahrenheit or lower immediately after the salting step.
2. Brining tanks shall be cleaned and sanitized prior to use. Different species of fish shall not be mixed in the same tank and brines shall not be reused unless there is an adequate process available to return the brine to an acceptable microbiological level.
3. Fish to be smoked shall be arranged without overcrowding or touching each other within the smokehouse oven or chamber to allow for uniform smoke absorption, heat exposure and dehydration.
4. Liquid smoke, generated smoke or a combination of liquid smoke and generated smoke shall be applied to all surfaces of fish to be smoked. Liquid smoke may be applied to the product prior to, at the commencement of, or during the process, while generated smoke shall be applied to the fish during the first half of the process and longer if necessary. If a combination of liquid smoke and generated smoke is used, the procedures for liquid smoke shall be followed and the generated smoke may be applied at any stage of the process.
5. Vacuum packaged or modified atmosphere packaged hot process smoked fish shall be produced by a controlled process that utilizes a monitoring system such as calibrated probes or dial thermometers to assure that all products reach the required temperature. The temperature readings shall be obtained by inserting an accurate temperature indicating device into, the thickest flesh portion of three or more of the largest fish in the smokehouse compartment. The coldest reading thus obtained shall be recorded in a fish smoking record as being the internal temperature of fish being smoked. The internal temperature of fish being smoked shall be obtained and recorded with the time taken at least three times during the operation of heating each load or batch of fish to assure that the required heat treatment has been accomplished. Each batch of smoked fish shall be identified as to the specific oven load, product temperature obtained and date processed. The temperature monitoring system shall be accurate to within 2 degrees Fahrenheit.
6. Vacuum packaged or modified atmosphere packaged hot process smoked fish shall be produced by a controlled process whereby each fish or fish portion shall be heated to an internal temperature of 145 degrees Fahrenheit or higher and maintained at 145 degrees Fahrenheit or higher for 30 minutes or longer. The smoked fish shall be brined to contain at least 3.5 percent water phase salt in the loin muscle of the finished product, except that vacuum packaged or modified atmosphere packaged hot process smoked fish which contain 100-200 parts per million sodium nitrite shall contain at least 3.0 percent water phase salt in the loin muscle of the finished product when processed in this fashion. Vacuum packaged or modified atmosphere packaged seafood processed in this fashion shall be brined to contain at least 3.5 percent water phase salt in the flesh portion of the product.
7. Vacuum packaged or modified atmosphere packaged cold process smoked fish shall be produced by one of the following processes:
1. Vacuum packaged or modified atmosphere packaged cold process smoked fish shall be produced by a controlled process that utilizes a temperature monitoring system positioned within the smoking chamber and results in a temperature that shall not exceed 90 degrees Fahrenheit during the drying and smoking period, which period shall not exceed 20 hours. The smoked fish shall be brined to contain at least 3.5 percent water phase salt in the loin muscle of the finished product except that vacuum packaged or modified atmosphere packaged cold process smoked fish which contain 100-200 parts per million sodium nitrite shall contain at least 3.0 percent water phase salt in the loin muscle of the finished product when processed in this fashion or;
2. Vacuum packaged or modified atmosphere packaged cold process smoked fish shall be produced by a controlled process that utilizes a temperature monitoring system positioned within the smoking chamber and results in a temperature that does not exceed 50 degrees Fahrenheit during the drying and smoking period, which period shall not exceed 24 hours. The smoked fish shall be brined to contain at least 3.5 percent water phase salt in the loin muscle of the finished product except that vacuum packaged or modified atmosphere packaged cold process smoked fish which contain 100-200 parts per million sodium nitrite shall contain at least 3.0 percent water phase salt in the loin muscle of the finished product when processed in this fashion or;
3. Vacuum packaged or modified atmosphere packaged cold process smoked sable fish shall be produced by a controlled process that utilizes a temperature monitoring system positioned within the smoking chamber and results in a temperature that shall not exceed 120 degrees Fahrenheit during the drying and smoking period, which period shall not exceed 6 hours. The smoked fish shall be brined to contain at least 3.5 percent water phase salt in the loin muscle of the finished product except that vacuum packaged or modified atmosphere packaged cold process smoked sable fish which contain 100-200 parts per million sodium nitrite shall contain at least 3.0 percent water phase salt in the loin muscle of the finished product when processed in this fashion.
8. Vacuum packaged or modified atmosphere packaged smoked fish shall be immediately cooled after processing to 50 degrees Fahrenheit or below within 5 hours and further cooled to a temperature of 38 degrees Fahrenheit or below within 12 hours after processing.

1. Brining Procedures: (VP/MAP)
1. Brine not to exceed 60°F at start
2. Brining procedures greater than 4 hours to be conducted under refrigeration of 38°F
3. Dry salting placed under 38°F refrigeration after the salting step
4. Brines not to be reused
5. Mixing of fish species in brines not allowed
2. Smoking Procedures: (VP/MAP)
1. Fish not overcrowded in smokehouse so as to promote absorption and exposure
2. Generated smoke applied to fish during the first half of process
3. Liquid smoke may be added before or during process
• Hot Smoking
1. Temperature probe of 3 or more fish with the coldest reading being recorded on process record
2. Temperature recorded 3 times during heating
3. Process record to include batch load temperature and date
4. 145°F/30 minutes and 3.5% wps. 145°F/30 minutes and 3.0% wps w/100-200 ppm nitrite
• Cold Smoking
1. Smokehouse or chamber temperature monitored
2. Processing parameters:
• 90°F/20 hours and 3.5% wps
• 90°F/20 hours and 3.0% wps w/100-200 ppm nitrite
• 50°F/24 hours and 3.5% wps
• 50°F/24 hours and 3.0% wps w/100-200 ppm nitrite
• Sablefish 120°F/6 hours and 3.5% wps
• Sablefish 120°F/6 hours and 3.0% wps w/100-200 ppm nitrite
3. Cooling Procedures: (VP/MAP)
• 50°F within 5 hours and 38°F within 12 hours

• brine strength; 
• brine to fish ratio; 
• brining time; 
• brining temperature; 
• thickness, 
• texture, 
• fat content, 
• quality, and species of fish; 
• drying time; 
• input/output air temperature, humidity, and velocity; 
• smoke density; 
• drier loading;
• accuracy of thermometers, recorder thermometer charts, high temperature alarms, maximum indicating thermometers, and/or digital data loggers; and
• accuracy of other monitoring and timing instruments (FDA, 1998).

Moisture analysis

Salt analysis

Water activity

Water phase salt calculation

Cold-smoked roe

Cold-smoked croaker

Cold-smoked eel

Cold-smoked flounder

 Cold-smoked haddock (finnan haddie)

Cold-smoked haddock fillets

Cold-smoked herring

Cold-smoked herring (bloaters I)

Cold-smoked herring (bloaters II)

Cold-smoked herring (hard-smoked herring)

Cold-smoked herring (kippered herring)

Cold-smoked herring (red herring)

Cold-smoked kingfish

Cold-smoked mackerel

Cold-smoked mullet

Cold-smoked salmon I

Cold-smoked salmon II

Cold-smoked salmon (German smoked salmon)

Cold-smoked salmon (hard-smoke or Indian-cure salmon)

Cold-smoked salmon (Scotch smoked salmon I)

Cold-smoked salmon (Scotch smoked salmon II)

Cold-smoked shrimp (peeled shrimp)

Cold-smoked shrimp (shell-on shrimp)

Cold-smoked yellowtail

Hot-smoked butterfish

Hot-smoked carp

Hot-smoked catfish

Hot-smoked eel

Hot-smoked goosefish

Hot-smoked haddock (smokies)

Hot-smoked herring (buckling)

Hot-smoked herring

Hot-smoked lake herring and whitefish

Hot-smoked mackerel

Hot-smoked mullet

Hot-smoked sablefish (kippered black cod)

Hot-smoked salmon I

Hot-smoked salmon II

Hot-smoked salmon (kippered salmon)

then at 76.7-82.2ºC (170-180ºF) for an h (Jarvis, 1987).

Hot-smoked Spanish mackerel

Hot-smoked squid (seasoned-smoked squid meat)

Hot-smoked sturgeon

21CFR172.175. 1997 Sodium nitrite. Title 21, part 172, section 175, Code of Federal Regulations, U.S. Government Printing Office, Washington, DC.

21CFR172.177. 1997. Sodium nitrite used in processing smoked chub. Title 21, part 172, section 177, Code of Federal Regulations, U.S. Government Printing Office, Washington, DC.

AFDO. 1991. Cured, Salted, and Smoked Fish Establishments Good Manufacturing Practices. Association of Food and Drug Officials, York, PA.

Corby, J. 1999. Personal communication, Director, Division of Food Safety and Inspection, Department of Agriculture and Markets, State of New York, Albany, NY.

Eklund, M.W., Peterson, M.E., Paranjpye, R., and Pelroy, G.A. 1988. Feasibility of a heat-pasteurization process for the inactivation of nonproteolytic Clostridium botulinum types B and E in vacuum-packaged, hot-process (smoked) fish. J. Food Protect. 51(9):720-726.

FDA. 1998. Clostridium botulinum toxin formation. Ch. 13. In Fish and Fishery Products Hazards and Controls Guide, 2^nd ed., p. 151-174. Department of Health and Human Services, Public Health Service, Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Seafood, Washington, DC.

FDA. 2001. Clostridium botulinum toxin formation. Ch. 13. In Fish and Fishery Products Hazards and Controls Guidance, 3^rd ed., p. 167-190. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Seafood, Washington, DC.

Jarvis, N.R. 1987. Curing of Fishery Products. Teaparty Books, Kingston, MA.

NMFS. 1984. Inspection and certification of vacuum packaged hot-processed smoked or hot-processed smoke-flavored salmon. NMFS Fishery Products Inspection Manual, Part III, Ch. 6, Sec. 2. National Marine Fisheries Service, Washington, DC.

Tanikawa, E., Motohiro, T. and Akiba, M. 1985. Marine Products in Japan, revised ed. Koseisha Koseikaku Co., Ltd., Tokyo.