Chapter 1: Acidified, Fermented, and Salted Fish and Fishery Products

• Potential Food Safety Hazard
• Clostridium botulinum
• Pathogens other than C. botulinum
• Control Measures
• C. botulinum control during processing
• C. botulinum control during storage
• Control of pathogens other than C. botulinum
• FDA Guidelines
• Process Establishment
• Critical Aspects of Processes
• Analytical Procedures
• Moisture analysis
• Drying oven procedure
• Microwave oven method
• pH analysis
• Colorimetric methods
• pH meter method
• Salt (NaCl) analysis
• Conductivity method
• Quantabâ method
• Water activity
• Water activity meter
• Water phase salt calculation
• Other analytical procedures
• Commercial Test Products
• Moisture
• Salt
• Water activity
• Acidifying, Fermenting, and Salting Processes
• Acidifying (pickling) processes
• Fermenting processes
• Salting processes
• References

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Potential Food Safety Hazard

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Clostridium botulinum

There are 2 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 types B and F. The nonproteolytic group includes C. botulinum type E and some types B and F.

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. The vegetative cells of all types are easily killed by heat.

Temperature abuse occurs when product is exposed to temperatures favorable for C. botulinum growth for sufficient time to result in toxin formation. Chapter 12 provides guidance about the conditions under which C. botulinum is able to grow.

Packaging conditions that exclude oxygen (e.g., vacuum packaging) favor the growth of C. botulinum, because oxygen is toxic to the pathogen. Vacuum packaging inhibits the growth of many spoilage bacteria, which increases the shelf life of the product. The safety concerns with these products is the increased potential for the formation of C. botulinum toxin before spoilage makes the product unacceptable to consumers. Both smoked and raw products in vacuum packaging and other reduced oxygen packaging require strict refrigeration (or frozen storage) throughout distribution.

C. botulinum forms toxin more rapidly at higher temperatures than at lower temperatures. The minimum temperature for growth of C. botulinum type E and nonproteolytic types B and F is 3.3ºC (37.9°F). For type A and proteolytic types B and F, the minimum temperature for growth is 10ºC (50°F). 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 7-10ºC (45-50°F) are not uncommon. Surveys of home refrigerators indicate that temperatures can exceed 10ºC (50°F).

C. botulinum can enter the process on raw materials. The spores of C. botulinum are very common in nature. They have been found in the gills and viscera of finfish, crabs, and shellfish. C. botulinum type E is the most common form found in freshwater and marine environments. Types A and B are generally found on land, but may also be occasionally found in water. It should be assumed that C. botulinum will be present in any raw fishery product, particularly in the viscera (FDA, 1998a).

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Pathogens other than C. botulinum

Pathogens can enter the process on raw materials. They can also be introduced into foods during processing from the air, unclean hands, insanitary utensils and equipment, unsafe water, sewage, and through cross-contamination between raw and cooked product (FDA, 1998b).

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Control Measures

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C. botulinum control during processing

• Adding sufficient salt to produce a water phase salt level (the concentration of salt in the water portion of the fish flesh) in the loin muscle of at least 5 %;
• Adding sufficient acid to reduce the acidity (pH) in the loin muscle to pH 5.0 or below;
• Reducing the amount of moisture that is available for growth (water activity) in the loin muscle to 0.97 or below (e.g., by adding salt or other substances that "bind" the available water); or
• Making a combination of salt, pH, and/or water activity adjustments that, when combined, prevent the growth of C. botulinum type E and nonproteolytic types B and F (to be established by a scientific study).

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

Because spores are known to be present in the viscera of fish, any product that will be preserved using salt, drying, pickling, or fermentation must be eviscerated prior to processing. Without evisceration, toxin formation is possible during the process.

Small fish, less than 5 inches (12.7 cm) in length (e.g., anchovies and herring sprats), that are processed in a manner that prevents toxin formation, and that reach a water phase salt content of 10 %, a water activity of below 0.85 (Note: this value is based on the minimum water activity for toxin production by Staphylococcus aureus), or a pH of 4.6 or less are exempt from the evisceration requirement.

The above discussed controls are not sufficient to prevent the growth of C. botulinum type A and proteolytic B and F. Strict refrigeration control during storage and distribution must, therefore, be maintained to prevent the growth of this group, unless one of the following conditions is also met:

• Sufficient salt is added to produce a water phase salt level in the loin muscle of at least 10 %;
• Sufficient acid is added to reduce the pH in the loin muscle to 4.6 or below; or
• The water activity in the loin muscle is reduced to 0.85 or below (e.g., by adding salt or other substances that "bind" the available water) (Note: this value is based on the minimum water activity for toxin production by S. aureus) (FDA, 1998a).

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C. botulinum control during storage

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Control of pathogens other than C. botulinum

• Managing the amount of time that food is exposed to temperatures that are favorable for pathogen growth and toxin production;
• Killing pathogens by cooking (covered in Chapter 3), pasteurizing (covered in Chapter 5), or retorting (covered by the low acid canned foods regulations, 21 CFR 113);
• Controlling the amount of moisture that is available for pathogen growth, water activity, in the product (covered in Chapter 4) for shelf-stable dried products; and in this Chapter for refrigerated products;
• Controlling the amount of salt or preservatives, such as sodium nitrite, in the product;
• Controlling the level of acidity or pH in the product (covered by the acidified foods regulations, 21 CFR 114 for shelf stable products; and for refrigerated acidified products in this Chapter).

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FDA Guidelines

Table 1-1. FDA guidelines for acidified, salted, and fermented fish and fishery products (FDA, 1998a).

Product	Minimum Water Phase Salt	Maximum aw	Maximum pH	Maximum In-Process and Finished ProductStorage Temperature	Maximum Time Product can be Exposed to Temperatures Above 10ºC (50ºF) or 21ºC (70ºF) During Processing (Excluding Time Above 60ºC (140ºF)
					>10ºC (50ºF)	>21ºC (70ºF)
Acidified "Pickled" fish, salted fish, fermented fish and similar products	-	-	5.0	10ºC (50ºF)	12 h	4 h
	-	-	4.6	None1	-	-
	5%	-	-	10ºC (50ºF)	12 h	4 h
	10%	-	-	-	-	-
	-	0.97	-	10ºC (50ºF)	12 h	4 h
	-	0.85	-	None2	-	-
	A combination of salt, pH, and/or water activity, established by a scientific study, that prevents the growth of C. botulinum type E and nonproteolytic types B and F			10ºC (50ºF)	12 h	4 h

¹Covered by the acidified foods regulations, 21CFR114. (Controls for these products are not required to be included in a HACCP plan).
²For more information, see Chapter 4.

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State Guidelines

New York Requirements For Shelf Stable Processing and Packaging of Caviar (Corby, 1999)

1. Minimum of 9% water phase salt
2. Pasteurization
3. Company must utilize a scheduled process developed by a qualified individual having extensive knowledge of thermal processing requirements of low-acid foods. This scheduled process must have FDA approval.

New York Requirements For Refrigerated Caviar (Corby, 1999)

1. 38°F storage minimum for products less than 5% water phase salt
2. 50°F storage minimum for products 5% or greater water phase salt

New York Guidelines for Processed fish (includes pickled, fermented and salted fish and fishery products) (Corby, 1999)

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.

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Process Establishment

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Critical Aspects of Processes

• Brine/acid strength;
• Brine/acid to fish ratio;
• Brining/pickling time;
• Brine/acid temperature;
• Thickness, texture, fat content, quality, and species of fish;
• Water phase salt, pH, and/or water activity of the finished product;
• Accuracy of thermometers, recorder thermometer charts, high temperature alarms, maximum indicating thermometers, and/or digital data loggers;
• Accuracy of other monitoring and timing instruments (FDA, 1998a).

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Moisture analysis

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Drying oven procedure (Woyewoda et al., 1986c; Hilderbrand, 1992)

1. Samples must be protected from water loss before weighing. After grinding or blending, material for analysis should be stored in filled containers with close fitting lids. Freeze samples for long term storage and after defrosting, mix thoroughly to re-distribute water, which may have drained to the bottom.
2. If an oven is unavailable when samples are received or for excessive numbers of samples, materials may be weighed into dishes and stored frozen until oven space becomes available. Prolonged drying time (over the weekend, etc.) may result in degradation and volatile loss.
3. Oven dried material readily absorbs moisture from the atmosphere. Samples should be cooled in a desiccator after removal from the oven and weighed immediately upon cooling.
4. Lipids absorb oxygen from the air and increase in weight on standing. High fat samples should be dried for the minimum time required.
5. Drying of high moisture or fat samples may be expedited by placing a disc of oven dried filter paper on the bottom of the drying dish before sample addition to spread and absorb the excess fluid and reduce splattering. Sometimes draping a pre-weighed filter paper disc over the sample will reduce loss by absorbing excess fluid and splattering fat.
6. Samples must be homogeneous and spread thinly (0.7 cm [1/4 inch] maximum) and evenly over the bottom of the drying dish.
7. If severe crusting is evident, drying time should be extended and in extreme cases the sample mixed with a small amount of weighed pre-dried sand.
8. When dealing with atypical or new products, the weight should be checked during the drying process to determine optimum drying time (to constant weight).

1. Drying dishes, disposable aluminum moisture pans.
2. Drying oven set at 103° ± 1°C (217.4° ± 1.8°F), maintain good ventilation.
3. Balance capable of weighing 0.001 g.

1. Place 3 pre-numbered empty moisture pans for each sample in drying oven at 103°C for 1 h. Cool in desiccator for 20 min.
2. Weigh each pan to the nearest 0.001 g.
3. Mix comminuted sample well. Add 2-10 g to pan and spread evenly over bottom. Weigh pan and contents.
4. Dry in oven overnight, cool in desiccator, and weigh again. Samples may be checked for constancy of weight by returning to oven for 1 h and reweighing.

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Microwave oven method (Hilderbrand, 1991)

1. Select a piece of fish that is most likely to have the lowest water phase salt (WPS). This will usually be the largest and thickest piece.
2. Cut a slice from the center of the piece big enough to blend evenly (1-1.5 pounds [0.5-0.7 kg]). Avoid bones.
3. Blend the sample until it is evenly ground into a fine particle size.
4. Dry 2 glass fiber sample pads (C.E.M. Corp., Matthews, NC) and 2 microwave-safe paper plates to constant weight in the microwave oven (about 1 min).
5. Zero the balance (use balance accurate to 0.1 g). Place 1 predried glass pad on the balance (use forceps). Place 1 paper plate containing the second glass pad on top of the first pad. Weigh and record weight.
6. Weigh and record weight of about 10 g (± 0.1 g) ground sample on the glass pad that is nested in the paper plate. Spread sample and cover with second pad and a second paper plate (inverted). Mark the top plate because it will not be weighed.
7. Remove sample, pads, and plates from balance then compress sample by pressing firmly on top plate (do not contaminate the sample with grease from fingers or other foreign matter).
8. Microwave for 30 s; lift top plate and pad using forceps, and blot moisture from the lower plate with paper towel.
9. Replace top plate and pads. Microwave for another 60 s. Record weight.
10. Invert the 2 pads on the lower plate, replace upper plate and microwave for an additional 30 s. Record weight. Repeat step 10 if necessary until no further weight loss is observed. Do not "overheat or burn" sample.
11. Record weight, compute weight loss (wtl), and calculate % moisture (%m) as weight loss divided by sample weight (wts):

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pH analysis

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Colorimetric methods for the determination of pH (21CFR114.90(b))

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pH meter method (Woyewoda et al., 1986a)

1. The pH meter must be allowed sufficient time for warm-up.
2. The electrode must be kept clean and free of occluded protein. A weak base or a mild detergent solution may be used to clean the electrode. Soaking in 8M urea for 2 h may also help. At no time should abrasion be used since this will lead to permanent damage.
3. The pH meter must be standardized carefully 1 pH unit on either side of the anticipated pH to ensure linearity in the pH range being measured. Commercially available pH standards are available for this purpose.
4. All standardization solutions and samples should be at room temperature (or at a common temperature) when being measured. The effect of temperature variation on pH of standards is noted on their label.
5. When drying the pH electrode, the lip should be patted with tissue rather than wiped to prevent build up of static electricity in the electrode.
6. Use good quality fresh pH standards. Some standards change pH with age or on extended exposure to air.
7. Electrode should be stored immersed in distilled water between readings.
8. When the electrode is removed from a solution the meter should be placed on "standby."
9. All electrodes age resulting in a slower speed of response. Reconditioning may help restore electrode response. Reconditioning by immersing electrode tip 15 s in 0.1 N HCl rinsing in tap water, immersing for 15 s in 0.1 N NaOH, rinsing and repeating each step several times. If this does not restore electrode, immerse in a 20% solution of NH₄F·HF (ammonium bifloride) for 2-3 min, rinse and check.
10. Some magnetic stirrers may influence readings. Check during standardization. It is not necessary to use a stirrer for routine pH checks of homogeneous sample.
11. Several samples should be used to compensate for biological variation among samples.
12. Sample pH must be determined immediately after maceration or blending of sample.
13. Samples should not be allowed to remain at room temperature for extended periods of time since bacterial activity will raise pH.
14. If using method B (without water addition) ensure good flesh/electrode contact.

Representative samples should be rendered homogeneous by comminuting in a food processor and then immediately analyzed. Several samples should be used.

1. pH meter equipped with combination pH electrode.
2. Blender or food processor.
3. Glassware: 25 ml and 50 ml beakers.
4. Thermometer.

The method involves blending a sample with water, measuring the electrical conductivity in milli-mho units of the solution by means of a conductivity meter and interpreting the results from standard curves.

Temperature control is critical for the measurements; all measured solutions must be at the same temperature as standards used for the preparation of the standard curve.

For samples of low salt content the proportion of water must be decreased. However, in the extreme, some errors may be encountered from the presence of natural salts since the procedure is not specific for sodium but rather takes into account all inorganic ionizable salts. For low concentrations, the silver nitrate titration procedure may be preferable.

Sample preparation

1. With a sharp knife cut sample into portions of approximately ½" x ½" (1.3 x 1.3 cm).
2. Comminute sample:
1. For lean fish (salt cod), place several portions into a dry blender jar and blend for 10 s intervals until material is shredded.
2. For fatty fish (herring, mackerel), comminute sample in a food processor until a homogeneous paste has been produced. If portions are very dry a blender may be used for comminution.
3. Pre-weigh portions of fish according to anticipated salt content, i.e., 10, 20, or 40 g portions for 18, 8, and 4% NaCl (wet weight) respectively.
4. Save some material for moisture determination.

Apparatus

1. Conductivity meter equipped with conductivity cell. For example, Radiometer CDM2 meter with CDC-114 flow cell (Radiometer Analytical Group, Westlake, OH) is appropriate.
2. Blender, Waring or equivalent.
3. Water bath, constant temperature, maintained at 20 or 25 ± 0.5ºC.
4. Glass wool or filter paper, Whatman #4.
5. Glassware: 100 ml measuring cylinders, funnels (glass or plastic), test tubes (18 x 150 mm), 100 ml beaker, 100 ml volumetric flasks.

Reagents

1. Sodium chloride: dry 30 g ACS grade NaCl at 110ºC overnight in 100 ml beaker and store in desiccator.
2. Sodium chloride standards: To 100 ml volumetric flasks add 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6 and 1.8 g portions (accurately weighed) of NaCl with 80 ml distilled water. Swirl to dissolve and make up to volume. Standards represent 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 1.8% w/v solutions.

Procedure

1. Calibration of meter.
1. Add standard solutions to clean test tubes and equilibrate in constant temperature bath - allow at least 15 min.
2. With attached bulb rinse cell with distilled water. Cell should be stored filled with distilled water or soaked for at least 30 min before use.
3. With function switch on "calibrate" and range at 5 milli-mho, set pointer to red calibration mark on meter.
4. Partially fill cell with standard solution of lowest salt concentration and dispel into waste container.
5. Fill and empty (back into test tube) cell several times with standard solution to ensure temperature equilibration of cell. Allow cell to rest in test tube (in bath).
6. Record reading from meter.
7. Proceed (without rinsing) to solution of next higher concentration, discarding first aliquot drawn. If meter goes off scale switch to 15 milli-mho range.
2. Salt in sample
1. Determine moisture of samples.
2. Blend preweighed samples of fish with 200 ml distilled water for 1-2 min until homogeneity is achieved.
3. Filter a portion of the blend through glass wool or Whatman #4 filter paper into a glass test tube to remove particles.
4. Place test tube in water bath at set temperature and allow at least 15 min for equilibration.
5. Rinse cell with distilled water at temperature of water bath; cell should always be stored partially filled with distilled water.
6. On conductivity meter set output to 5 milli-mho and function switch to "calibrate." With calibration knob adjust meter so that needle rests on red calibration mark. Set switch to "measure."
7. With rubber bulb attached to cell partially fill cell chamber with filtered sample solution to rinse. Dispel into waste beaker.
8. Refill chamber with new solution ensuring that coil in cell is immersed in solution. Leave cell in the test tube (in water bath) and fill and empty cell several times to ensure constancy of and homogeneity of solution. Record reading from meter. If reading is off scale set meter to 15 milli-mho. Dispel solution.

Calculations

1. Standard Curve.

On graph paper plot meter reading vs. g NaCl/100 ml.
2. Salt Concentration in Samples

From the meter reading obtained for each solution determine from the calibration graph a final NaCl concentration. Salt in sample may be calculated as: Where: C = concentration of NaCl in sample expressed as % on a wet weight base
M = moisture as % by weight
R = %NaCl reading determined from graph
V = volume (ml) distilled water added
W = weight (grams) of sample used.

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Quantabâ method (Hilderbrand, 1991; ETS, 1998)

1. Select a piece of fish that is most likely to have the lowest salt content. This will usually be the largest and thickest piece.
2. Cut a slice from the center of the piece big enough to blend evenly (1-1.5 pounds [0.5-0.7 kg]). Avoid bones.
3. Blend the sample until it is evenly ground into a fine particle size.
4. Place exactly 10 g of sample in a 250 ml beaker.
5. Add 90 ml (or 90 g) of boiling distilled water. Use boiling tap water only if a test with a Quantab (Environmental Test Systems, Inc., Elkhart, IN) shows the tap water to be salt free.
6. Stir for 30 s, wait 1 min (or longer if particles are large), and stir another 30 s to insure all salt is extracted from sample.
7. Place lower end of salt titrator into sample solution. Do not allow solution to reach yellow completion string at top of titrator.
8. Wait for solution to saturate titrator and turn yellow string dark blue. Note where the tip of the yellow/white peak on reacted titrator falls on the numbered scale in Quantab units.
9. Determine salt concentration from calibration table on Quantab container. Multiply by dilution factor of 10.
10. Note: Filtration of the sample solution may be needed to prevent obstruction of the titrator.

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Water activity

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Water activity meter (AquaLab CX2)(Decagon, 1997)

1. Place AquaLab (Decagon Devices, Inc., Pullman, WA) on a level surface and in a location where the temperature remains fairly stable.
2. Plug in AquaLab and turn on power switch. The display will show all zeros in about 15 s. The instrument requires a warm up time depending on the ambient temperature.
3. Verify the calibration against a known salt standard before and after each sample run. For batch processing, calibration should be verified more frequently.
4. Make sure sample to be measured is homogeneous. Spread the sample material in the bottom of the disposable sample cup, covering the bottom of the cup if possible.
5. Place a sample in the sample drawer. Close the drawer and turn the knob from "Open/Load" to "Read." When the reading is complete, the instrument will beep continuously and the decimal points will blink.
6. The display will show a final a_w and temperature of the sample in degrees Celsius. The drawer can be opened at this time and the reading will be retained until the next sample is started. Most readings take less than 5 min.

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Water phase salt calculation

Calculate water phase salt (WPS) as % salt (%S) divided by % salt + % moisture (%M) multiplied by 100 (Hilderbrand, 1992).

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Other analytical procedures

• pH of acidified foods (AOAC, 1995a).
• Potentiometric method for the determination of pH (21CFR114.90(a)).
• Titratable acidity (21CFR114.90(c)).
• Salt (chlorine as sodium chloride) in seafood: Potentiometric method(AOAC, 1995c).
• Salt (chlorine as sodium chloride) in seafood: Volumetric method(AOAC, 1995b).

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Commercial Test Products

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Moisture

Table 1-2. Commercial test products for moisture.

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Salt

Table 1-3. Commercial test products for salt.

Test Kit	Analytical Technique	Approx. Total Test Time	Supplier
CDM210 Conductivity Meter	Conductivity		Radiometer Analytical Group A division of Struers Inc. 810 Sharon Drive  Westlake, Ohio 44145-1598 Mr. Nick Mizencko  Phone: 440/ 871-5975  Phone: 1 800/998-8110 Fax: 440/899-1139  E-mail: analytical@clevelandoh.com Web: http://www.radiometer.tm.fr/index.html
Quantab chloride titrators		20-45 min	Environmental Test Systems, Inc. P.O. Box 4659 Elkhart, IN 46514 Phone: 1-888-387-7874 Web: http://www.etsstrips.com/Default.html
Ultra S® Salt Measurement System	Ion selective electrode	5-15 min	Lazar Research Laboratories, Inc. 731 N. Labrea Ave. Los Angeles, CA 90038 Phone: 213/931-1433 Fax: 213/931-1434 E-mail: service@lazarlab.com Web: http://www.lazarlab.com

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Water activity

Table 1-4. Commercial test products for water activity.

Test Kit	Analytical Technique	Approx. Total Test Time	Supplier
AquaLab CX2 water activity meter	Cooled mirror condensation dewpoint sensor	3-4 min	Decagon Devices, Inc. 950 NE Nelson Court Pullman, WA 99163 USA  Phone: 509-332-2756  Fax: 509-332-5158 E-mail: sales@decagon.com Web: http://www.decagon.com
A2101 Water Activity Meter	Relative humidity sensor	4-6 min	Rotronic Instrument Corp. 160 E. Main Street Huntington, NY 11743 Phone: 516/427-3898 Fax: 516/427-3902 Web: http://www.rotronic-usa.com

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Acidifying, Fermenting, and Salting Processes

Acidifying "pickling" processes

Bismarck herring

Cut spiced herring I

Cut herring across the body in pieces 1-2 inches (2.5-5.1 cm) long. Pack pieces in wooden tubs holding 10-20 pounds (4.5-9.1 kg), or in kegs holding 100 pounds (45.4 kg). Mix together the dry spices. Place a few spices, 1-2 bay leaves, and several slices of onion in the bottom of the tub or keg, then a layer of cut herring, over which are laid onion slices and a sprinkling of spices. Repeat until tub or keg is filled. Dissolve sugar in the water and mix with vinegar. Cover cut herring with sugar-vinegar mixture. Store at 4.4ºC (40ºF) for 10 d to cure. At the end of this time, if the fish are to be repacked, fill cut pieces into 8, 16, or 32 ounce (237, 474, or 947 ml) glass containers. Use the curing vinegar to fill containers but strain it before reuse. Some packers prefer to use fresh vinegar diluted to 3% acidity. Place a few spices, 1-2 bay leaves, and a little chopped onion in each jar. Vacuum seal the containers, wipe containers clean and label (Long et al., 1982).

Cut spiced herring II

The shelf life of this product depends upon the care in manufacture and temperature of storage. If held at 4.4ºC (40ºF), the product should remain in good condition for at least 6 months. Exposure to light causes deterioration more rapidly even if held under refrigeration, as in a refrigerated showcase (Long et al, 1982).

Escabeche

Cut fish into small serving portions. Wash thoroughly, drain, and place in 90° salimeter brine for ½ h. Wipe the fish dry. Heat a minced clove of garlic, 6 bay leaves, and a few red peppers in olive oil until they are light brown, and then cool. Cook onions in the oil until they are yellow. Add black peppers, cumin seed, marjoram, and vinegar. Cook slowly for 15-30 min and cool. Pack cold fish into sterilized jars with the rest of the bay leaves and red peppers. Fill the jars with sauce and close immediately. Store in a cool place for at least 24 h before use (Jarvis, 1987).

Fish pickled in wine

Thyme may be substituted for rosemary, and the spice combination may be otherwise altered to suit the individual preference (Long et al., 1982).

Gabelbissen

Use fresh fat herring. Cure round herring 30-40 h in 90º salimeter brine. In some instances, however, this preliminary brine cure is omitted and the fresh fish are packed directly into barrels. Scatter a special curing mixture on the bottom of the barrel between the fish and over each layer. Pack the herring with bellies straight up and tails overlapping. Pack layers of fish in rather loosely. Head up the barrels and put them in cold storage at about 4.4ºC (40ºF), for several months to cure and ripen.

At the end of about 3 months, remove the herring from storage, drain well, head, bone, and skin. Cut the fillets into sections and pack in glass containers, or pack whole fillets in oval or oblong flat cans. If desired, lay a bay leaf and a thin slice of lemon in each can. Fill the containers with the original curing brine diluted ½ with distilled vinegar or pack in wine sauce, dill sauce, or curry sauce. Seal the containers and hold under refrigeration until sold (Long et al., 1982).

Gaffelbiter

Cut fat, mild-cure salt herring into fillets and skin. Freshen in running water 2-3 h depending upon size of the herring, whether mild or heavy cure, and local market preference. Cut fillets into 1 inch (2.5 cm) sections; pack into tubs or crocks and mix in the chopped onions and spices; cover with distilled vinegar. Store in a cool place (about 4.4ºC [40ºF]) and allow to cure for 48 h. Then repack herring pieces in sterilized containers. Fill containers with either fresh vinegar or the vinegar used for curing, but strain before using. Seal containers and pack for market distribution (Long et al, 1982).

German delicatessen anchovies

The following preservation and spicing mixtures are given for 1-liter tins:

Table 1-5. Ingredients for German delicatessen anchovies.
 

Ingredient	No. 1 g	No. 2 g	No. 3 g
Luneberg salt	125-150	150
Liverpool salt			150
Sugar	50	100	100
Sodium nitrate	1.5	2
Jamaica pepper	3.5		4
Black pepper	1	2	3
Cayenne pepper			0.04
Cloves	1.5	1.5	2
Mace	1		1
Sandlewood		1	1
Cinnamon	0.5		1
Ginger	0.5	1	2
Spanish hops		1	2
Bay leaves	1.5	2	2

Weigh out salt, sugar, and sodium nitrate and thoroughly mix together. Then weigh out the remaining spice ingredients and mix thoroughly with the salt-sugar mixture.

Spread some of the spice mixture on the bottom of the 1-L tins and between each layer of fish. Place the first layer of fish in rows with backs down; the second layer in rows obliquely to the rows below with backs of the fish down. Repeat until there are 4 layers in the tin. Place 1 bay leaf on the bottom of the tin, 1 between each layer, and 1 on top. The lid is then put on and, for local use, made airtight with paraffin. Store the tins in a cool place, preferably under refrigeration (Long et al., 1982).

Herring in sour cream sauce

Use the mild-cured herring (Holland style). Fillet and save the milts. Soak fillets in cold water for 2 h. Rub the milts through a fine sieve. Drain fillets of surplus moisture. Boil together the vinegar, wine, and mixed spices for 3-5 min; cool and remove spices. Blend together the sour cream, sweet cream, milts, and cooled vinegar. Pack fillets in a large container with sliced onions, cover with the cream-vinegar sauce, and marinate in a cool place for 1 week. Pack fish and onion slices in glass jars with the sauce (Long et al., 1982).

Herring in wine sauce

Put all the ingredients into a large jar with cover. Place jar in a large enough cooking pot to which water can be added to the depth of the ingredients in the jar. Bring water to a boil and boil for 2 h. Then allow jar to stand overnight. When sauce is ready to be used, strain to remove the spices.

If vinegar-salt cure herring are used, cut the fillets in pieces of suitable size, rinse in freshwater, drain, and pack in sterilized jars with a few fresh spices and a slice of lemon. Fill jars with wine sauce. Seal.

If ordinary salt herring are used, fillet and freshen in water. Drain the fillets; pack in a stoneware crock; cover with 1 quart (946 ml) distilled vinegar (3% acidity) and let stand for 48 h. Remove the fillets from the vinegar and cut into pieces of suitable size; pack into sterilized jars and fill with wine sauce (Long et al., 1982).

Matjeshering

Wash the herring and scale. Remove the gills and pull the intestines out through the gill opening so that the throat or belly walls are not cut open. Soak the cleaned fish in a 7% white wine vinegar solution for 12-18 h (they must be removed from this solution before the skin becomes soft and flabby). Wipe fish dry. Roll in a curing mixture of: 2.2 pounds (1 kg) salt, 1.1 pound (0.5 kg) brown sugar, and 4 ounces (113 g) sodium nitrate.

Pack herring in a small keg in straight layers with backs up. Scatter some of the curing mixture between the fish as they are packed and sprinkle some over each layer. Allow to stand 24-48 h. Then repack fish, using the original brine that has collected. If not enough brine has formed, make up additional brine to cover herring by boiling together 1 part salt-sugar mixture (as above) to 4 parts water. Cool and filter before using. Close kegs and store at 4.4ºC (40ºF) for at least 1 month before using (Long et al., 1982).

Mustard or Kaiser-Friedrich herring

Pickled and spiced mackerel fillets

Clean fish and wash thoroughly, and cut into fillets, removing the backbone. Divide the fillets into 2 inch (5.1 cm) lengths and dredge with fine salt. Pick up pieces with as much salt as will cling to the flesh and pack in a crock or tub. Let the fish stand for 1-2 h, then rinse in freshwater. Cook the vinegar, water and other ingredients slowly and gently for 10 min after reaching boiling point. Add the fish and cook slowly for 10 min longer, counting from the time at which the solution again begins to boil after the fish has been put in. Remove the fish and allow the pieces to drain, then pack them in sterilized jars, adding some chopped onion, a bay leaf, a few spices, and a slice of lemon to each jar. Strain the spice vinegar sauce and bring to a boil. Fill the containers with hot sauce and seal immediately. Store in a cool, dry place (Long et al., 1982).

Pickled eels

Pickled haddock fillets

The fish are covered with a solution of 2 parts vinegar and 1 part water, adding a small piece of alum about the size of a walnut. Boil slowly until the fish may be pierced easily with a fork. After cooling, the product is packed in glass containers, adding a few fresh spices, a bay leaf, and a slice of lemon around the side of the jar for decoration. A few slices of onion may also be packed with the fish. Strain the vinegar sauce, heat it, and pour over the fish until the top is well covered. Seal the containers immediately. For maximum preservation, store under refrigeration (Long et al., 1982).

Pickled herring for rollmops, cut spiced, or Bismarck herring

For final manufacture, repack herring in kegs and fill with a solution of distilled vinegar diluted with water to a 3% acidity and containing sufficient salt to test 35º salimeter. Dressed herring may be cut into fillets or the backbone may be removed leaving the fish otherwise whole before repacking. Store repacked kegs in cold storage at 1.1ºC (34ºF).

Begin the final process by soaking the herring in a tank of cold water 8-10 h. Remove the herring and drain. Place the fish in a solution of vinegar, salt and water for 72 h. Make up the solution in the following proportions: 1 gallon (3.79 L) of 6% white distilled vinegar to 1 gallon (3.79 L) of water, and 1 pound (454 g) of salt. Be certain the fish are well covered with the solution. Then make them up into cut spiced herring, rollmops, or Bismarck herring (Long et al., 1982).

Pickled mussels I

Pickled mussels II

Pickled octopus meat

Pickled oysters I

Remove oysters from liquor. Strain liquor and add sufficient salted water to make 3 pints (1.4 L). Simmer liquor over low heat. When it is near the boiling point, add a few oysters at a time and cook until fringe curls. Cool. Make a sauce of the cooking liquor, vinegar, wine, and spices. Simmer for 30-45 min then cool and strain. Pack oysters in glass jars with a bay leaf, slice of lemon, and a few fresh spices in each jar. Fill jars with strained sauce. Seal jars and cure for 10-14 d in a cool, dark place (Long et al., 1982).

Pickled oysters II

Blanch oysters in their own liquor until fringe curls. Remove and cool oysters. Bring the oyster liquor to a boil, then cool. Cook vinegar and spices over low heat for 5 min. Strain vinegar to remove spices. Combine oyster liquor and spiced vinegar and cool. Pack the oysters in glass jars with a bay leaf and thin slice of lemon in each jar. Fill containers with the cool sauce and seal immediately. Store under refrigeration (Long et al., 1982).

Pickled salmon I

Cut salmon into individual serving portions. Wash well in cold water, drain, and dredge in fine salt. Allow to stand for 30 min, drain off leakage, and slowly simmer salmon until done. Place the warm fish pieces in an earthenware crock. Cover with a vinegar-spice sauce made as follows: Sauté onions in olive oil slowly until they are yellow and soft. Add remainder of ingredients and simmer gently for 45 min. Cool sauce, then pour it over the fish making sure that all pieces are covered. Let fish stand in sauce for 48 h then repack in pint (0.5 L) jars with a slice of lemon, slice of onion, and 1 bay leaf inserted around sides of jar for decoration. Filter the spice sauce before pouring it over the fish; fill container with sauce, then seal. This product should be held under refrigeration at 4.4ºC (40ºF) (Long et al., 1982).

Pickled salmon II

Some mild-cure salmon is cut into 2 inch (5.1 cm) cubes, freshened in cold water, and packed in spiced vinegar sauce or in wine sauce (Long et al., 1982).

Pickled spiced shrimp

Pickled sturgeon, pike, pickerel, salmon, herring, trout, and other fish

Wash fish well and cut into small, 2-4 ounce (57-113 g), individual serving size portions. Dredge pieces in fine salt and store for 1-3 h. Rinse off salt, dry the pieces, and brush with cooking oil. Broil the pieces over a hot fire until both sides are light brown, brushing with cooking oil during the process. Cool fish and pack in glass containers with 1-2 slices of lemon, bay leaves, onion, and a scattering of rosemary, whole black peppers, and whole cloves between layers of fish. Fill jars with a marinade made of white wine, vinegar and water, and seal immediately. Store in a dry, cool place (Jarvis, 1987).

Rollmops

Cut each dill pickle lengthwise into 4 parts, then each of these across the center, making 8 pieces in all.

Roll the fillets around a piece of pickle and fasten with a fresh clove. A clove serves the purpose just as well as a toothpick and adds to the attractiveness of the pack.

Place 1 teaspoon (10 ml) of mixed used spices on the bottom of the jar, then pack the fish. With a medium sized herring, 3 rolls will pack nicely into a No. 306 jar (6 fluid ounces [178 ml] capacity) if placed on end. Decorate around the sides with a couple of chili peppers and a bay leaf. Add sufficient pickle to fill (from 25 to 30 ml) (this is about equivalent to 2 level tablespoonful). The net weight should be 5½ ounces (156 g) or over. Seal the jars immediately after packing. Vacuum sealing is preferable.

Store is a cool place. Cold storage at about 1.7ºC (35ºF) is advisable to ensure longest preservation.

Note: If vinegar-salt-cured herring are used, the preparation and preliminary vinegar-cure steps will be unnecessary. (It is believed that a better product will be obtained if the vinegar-salt-cure herring are used.) In this case, the spice-vinegar sauce should be diluted to 3% acidity and the rollmops should be cured in the spice sauce for 10 d. They should then be repacked in jars with a few spices and the jars filled with fresh 3% vinegar to which are added 2 tablespoons (59 ml) sugar and 1 tablespoon (30 ml) salt per quart (946 ml). Store at 1.1-4.4ºC (34º-40ºF) (Long et al., 1982).

Russian sardines

Pack fresh small herring (5-7 inches [12.7-17.8 cm]) in 90-100º salimeter brine as soon as possible after catching. Hold in the brine about 10 d until they are thoroughly salt-cured or struck through. After salting, remove heads, pulling out the viscera with the same stroke of the knife without tearing the belly open. Wash in clean water and place on wire trays for draining. Allow to drain for several h. Sort for size and pack each size separately in small kegs holding about 7 pounds (3.2 kg) of fish. For packing, mix all spices and flavorings together. Scatter a thin layer of these ingredients in the bottom of the keg and a layer of herring with backs up. Lightly press down layer, scatter another thin layer of spice ingredients over fish, and add a little vinegar. Repeat this process until keg is filled. Pour in as much vinegar as the keg will hold and head up the keg. The fish is ready for the market in from 4-5 d (summer) to 3-4 weeks (winter). Refrigerate at about 4.4ºC (40ºF) for a 1-year shelf life (Long et al., 1982).

Scandinavian anchovies

Cure 25-30 pounds (11.3-13.6 kg) of bristling for 12 h in brine made of 4½ pounds (2.0 kg) of Liverpool salt and 7 quarts (6.62 L) of water. Drain the fish on a wire screen. Make up a spice mixture with all spices well pulverized and the ingredients thoroughly blended: 2¼ pounds (1.0 kg) Luneberg salt, 3 ounces (85 g) black pepper, 3 ounces (85 g) allspice, 3 ounces (85 g) sugar, ½ ounce (14 g) cloves, ½ ounce (14 g) nutmeg, ½ ounce (14 g) cayenne.

Use half of the spice mixture and mix well with the sprats. Pack them in a large container and cure for 14 d. Repack in individual containers in layers, bellies up. Scatter some of the remaining spice mixture between each layer with pieces of chopped bay and cherry leaves. On the bottom and top of each container, lay 2 whole bay leaves. The brine formed in the original spice cure is filtered and used to fill the small containers after packing. During the first few d after the containers are closed, roll them about and invert them at least every other day.

Tin containers are preferred to wooden kegs which are often leaky and the airtight seal of a tin container permits a longer period of preservation.

For 40 pounds (18.1 kg) of bristling prepare the following spice mixture well pulverized and thoroughly blended: 2¼ pounds (1 kg) Luneberg salt, 7 ounces (198 g) black pepper, 7 ounces (198 g) allspice, 7 ounces (198 g) sugar, 1-1/8 ounce (32 g) cloves, 1-1/8 (32 g) ounce nutmeg, 1-1/8 ounce (32 g) Spanish hops.

Place fresh bristling in strong salt brine from 12-24 h. Drain on a screen, and pack in layers in small kegs after being rolled in a spice-curing mixture. Scatter some of this mixture between the layers of fish. At the top, bottom, and in the middle of the keg, lay several bay leaves. Pack the kegs tightly and roll them about or invert them for 14 d. Repack the anchovies in tins in 14 d in summer or after 4-8 weeks in winter.

Wash brine-salted bristling in light brine testing 40º salimeter. Drain and pack loosely in new barrels with some of the following spice mixture scattered between each layer of fish. This quantity of spice mixture is for 1 barrel original weight: 2 pounds (0.9 kg) black peppers, 1 pound (0.5 kg) allspice, 1½ pounds (0.7 kg) sugar (best raw), 1 pound (0.5 kg) sodium nitrate, 1 pound (0.5 kg) bay leaves, 6 ounces (170 g) Spanish hops, 2 ounces (57 g) mace, 2 ounces (57 g) cloves, 2 ounces (57 g) cinnamon, 2 ounces (57 g) ginger.

Filter the brine used for washing and the original brine and pour into the barrels after filling. Place the barrels in cool storage for several months for the fish to ripen or acquire and aromatic flavor. Roll the barrels about daily or at the least, at intervals of 2-3 d. When the fish have completely absorbed the spice flavor, repack in small individual containers, small kegs holding about 7 pounds (3.2 kg), cans holding from 2-5 pounds(0.9-2.3), and glass jars. Filter the brine used in curing and fill into the containers when they have been packed with fish. In summer 0.5% benzoic acid may be added to the brine (Long et al., 1982).

"Scotch-cured" herring

Table 1-6. Sizes for Scotch-cured herring.
 

	Inches	Cm	No. per 250-Lb. (113.4 kg) Scotch-Style Barrel
Large fulls	11¼	28.6	600-650
Fulls	10¼	26.0	700-750
Matfulls	9¼	23.5	800-850
Matties	8½	21.6	900-1,000

When sufficient "pipped" herring have been sorted "rouse" with salt by placing them in a large tub and covering them with fine salt; mix thoroughly by hand until the entire surface of each herring is evenly covered with salt. Pack either in tight 250 pound (113.4 kg) or 125 pound (56.7 kg) barrels. The standard Scotch barrel (250 pounds [113.4 kg]) is made of staves about ¾ inch (1.9 cm) thick; 30 inches (76.2 cm) high and has a head 17 inches (43.2 cm) in diameter; its capacity is 32 U.S. gallons (121.1 L). Carefully pack the fish in layers with backside down, taking care to keep the rows even so the layers are uniform. Pack the second layer at right angles to the first layer. Using Liverpool No. 2 fishery salt, half-ground Spanish salt, or half-ground double washed California salt, sprinkle enough salt over each layer to almost cover them. Fish containing milt or roe require more salt. But, do not use an excess of salt, as the completely cured fish should be free from undissolved salt.

Some herring salters allow the fish to make their own pickle; others add some saturated brine immediately after the fish are packed into barrels. Adding the brine is advisable during warm weather and when curing extra large herring for it enables the pickle to "strike the bone" immediately from the inside and outside as well.

On the first or second day after salting when the herring have settled somewhat, fill the barrel with herring of the same day's pack. Put the head on the barrel and place it on its side for 8-10 d. At the end of this time, up-end the barrel, head up, and remove the head. Bore a bunghole in the center of the side of the barrel and drain the pickle as far down as the bunghole. Pour the drained pickle over the top tiers of fish in the barrel 2-3 times, which will cause the herring to settle. Again fill the barrel with salted herring of the same day's pack. In repacking the barrel, sprinkle a very small quantity of salt over each additional layer except the last layer to which no salt is added. When the layers of salted fish reach the top of the staves, the head is "jumped" in. After tightening the hoops, place the barrel on its side and fill with saturated brine. Replace the bung (Long et al., 1982).

Contents

Fermenting processes

Ayu-sushi

Black fermented squid meat

Cured ayu in koji

Cured Atka mackerel or flat-fish

Cured fermented ayu in sake-lees

Cured fermented abalone in sake-lees

Cured herring in koji

Cured herring in rice bran

For dried herring meat, soak in freshwater for 2-3 d. Wash thoroughly and drain. Make a paste of rice bran and saturated salt solution and cure softened herring and rice bran paste in a barrel (Tanikawa et al., 1985).

Cured mackerel in koji

Cured mackerel roe in koji

Cured octopus or squid meat in koji

Cured puffer fish meat in rice bran

Cured puffer fish roe in rice bran

Cured salmon or cod meat in sake-lees

Cured salmon-"sushi"

Cured sardine in rice bran

Cured sea bream in koji

Cured squid meat

Fermented ayu milt

Fermented ayu roe

Fermented bonito meat

Fermented bonito stomach

Fermented bonito viscera

Fermented meat and viscera of ayu

Fermented mixture of ayu roe and milt

Fermented sea-cucumber viscera

Fermented viscera of ayu

Fermented "sushi"

Liquid fermented sand fish (Arctoscopus japonicus) sauce

Ordinary fermented squid meat

Mix together 100 parts of meat strips, 4-8 parts liver, and 20 parts salt in summer (15 parts salt in winter) in a barrel and store. Stir the mixture 2-3 times a day during the first week, then seal the barrel tightly and store (Tanikawa et al., 1985).

Pasty fermented sea urchin

Pulpy fermented sea urchin

Red fermented squid meat

Watery fermented sea urchin

White fermented squid meat

Contents

Salting processes

Alaska Scotch-cure herring

Anchovies, Spanish style

Hold tanks at 26.7-32.2ºC (80-90°F) for about 4 months. The anchovies are ready when the flesh is red from skin to backbone and has a strong, sharp flavor.

Remove anchovies from tank, drain, and pack in round tins holding 8, 14, or 28 pounds (3.6, 6.4, or 12.7 kg). Press fish to remove excess moisture and oil. Seal cans and store (Jarvis, 1987).

Appetitslid

Brine packed cod

Brine-salted mackerel

Brine-salted mullet

Brine-salted sablefish

Brine-salted salmon roe

Caviar, cod

Caviar, fresh grain, Russian

Caviar, grain in barrels (Russia)

Caviar, lake whitefish

Caviar, lumpfish

• Water phase salt >3.95%, a_w <0.978, pH <5.2
• Water phase salt >4.67%, a_w <0.974, pH <5.6
• Water phase salt >5.56%, a_w <0.968
• pH <5.0

Caviar, pickled grainy

Caviar, pressed (Russia)

Caviar, salmon

Caviar, salmon Russian method

Caviar, sturgeon (U.S.)

Caviar, sturgeon in jars (Russia)

Corned herring

Dry-salted mullet roe

Dry-salted salmon roe

Dry-salted sardines and saury

Hard salted salmon I

Hard-salted salmon II

Matje cure herring

Mild cure salmon

Norwegian-cure herring

Round cure herring

Salted Atka Mackerel

Salted cod or Alaska pollock roe

Salted cod tongues

Salted herring roe

Salted lake herring

Salted jellyfish

Salted mackerel fillets

Salted pressed pilchard

Salted river herring

Salted salmon bellies

Salted yellowtail

Salting salmon

Scotch cure herring

Slack-salted cod

Slack-salted herring

Slack-salted salmon

Slack-salted salmon eggs

Split cure herring