Oct., 1921
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
The Preservation of Fish Frozen in Chilled Brine. I-The
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Penetration of Salt',
By L. H.Almy and E.Field BUREAUOB CHEMISTRY, U. S. DEPARTM'ENT OB AGRICWLTURE, WASHINGTON, D. C.
The advantage derived from storing fish in the hard frozen condition in order to preserve them during the period when production exceeds consumption is well recognized throughout the greater part of the country. Judging from the results obtained, the methods now employed for the freezing and storing of fish1* appear to be quite satisfactory. At the present time efforts are being made to introduce new processes for freezing fish. These processes involve the use of chilled salt brine in freezing the product, the latter being in direct contact with the solution for periods varying from 15 min. to 3 or 4 hrs. until hard frozen. The detailed procedures recommended by the authors of these new methods differ in some respects. The fish may be immersed in the cold brine after they have been chilled to near 32" F.2or without having been thus precooled,s or they may be frozen in open shipping cases by passing chilled brine through the goods.* Practical experiments performed by European investigators both on a laboratory scales and under commercial conditionsa indicate that the freezing of fish in brine has many points in its favor. It does not take as long to freeze in brine as it does in air. During the slow freezing by the latter method f%h lose in weight somewhat, as the result of a slight evaporation of water. This, of course, does not take place in fish while being frozen in brine. It has been thought by some that the method would be cumbersome to operate. It is possible, however, by the use of suitable mechanical devices1 to make the process continuous and to freeze fish with very little labor. It seems to be well adapted for use on fishing boatss and to be practical for the commercial freezing of fish on land.9 Droogleever Fortuyn,'Owho examined histologicallythe flesh of fish frozen in air and in brine, states that the muscle fibers of fish frozen according to the latter method "swelled up and returned to their original form better than in other cases, when thawed." According to Reuter," during the freezing in brine the fluids in the muscle fibers near the outer surface of fish congeal practically i n situ, while the fluids in the muscle fibers deep in the body of a large fish exhibit a tendency to withdraw toward the center of the fibers, eventually forming single columns of ice crystals. Also, in the case of fish frozen slowly, as in the present air process, the separation of fluids is much more marked, the water escaping from the ruptured sheaths of the fibers and accumulating in the f o r p of large ice crystals between compressed masses of fibers. It would seem that, since less change occurs in the muscular tissue of fish frozen in brine than in that of fish frozen in air, the former would more nearly resemble fresh unfrozen fish in texture and flavor than would the latter. There thus appear to be advantages to be derived from the use of chilled brine for freezing fish. It is not the object of this paper, however, to discuss in detail the relative merits of these two general processes. A just comparison must necessarily await such time as the trade has given the new method a thorough trial, as little is now known by the trade of this country concerning the ease and economy of its operation under commercial conditions. For the successful preservation of fish in freezer storage it is necessary to limit the evaporation of water from the fish to a minimum. This is accomplished efficiently and economically by means of an ice glaze. Such a glaze, by retarding the drying out of the fish, tends to preserve not only the 3 Received M a y 19,1921.
* Numbers in text refer to References at end of paper.
quality of the flesh but also the external appearance. I n deciding concerning the usefulness of the brine method for preparing fish for freezer storage, it is important for one to know whether fish which have been frozen by that method will retain a glaze for a reasonable period of time. The Food Investigation Board of Great Britain,12 which touched upon this question in connection with its general study of the brine freezing of fish, found that salt was retained by the surface of the fish, the amount being directly proportional to the concentration of the brine and very nearly proportional to its temperature. The conclusion was reached "that, if glazing be insisted upon as necessary for prolonged preservation, brine freezing is a t a disadvantage." Plank, Ehrenbaum, and Reuterla report some experiments which indicate that the penetration of salt into the tissues of fish is not as great when the temperature corresponds to a point on the ice curve of the freezing solution as when the temperature is higher. The amount of salt absorbed when fish were frozen in unsaturated brine solutions a t or slightly below their freezing points was found to be comparatively small. I n view of the prominent part which the process of glazing plays in the successful preservation of fish in freezer storage in this country, a study was made of the degree of salt penetration into the skin and superficial tissues of weakfish (Cynoscion regalis), flounders (Pseudopleuronectesamericanus), herring (Clupea harengus), and whiting (Merluccius bilinearis), during immersion for different periods of time in cold brines of different temperatures and concentrations.
METHODS FREEZING APPARATUS-Awooden
tank 46 in. long X 23 in. wide x 36 in. deep, lined with galvanized iron was fitted with brine coils lining the sides and ends. The flow of brine through the coils was regulated by means of inlet and outlet valves. The inlet pipe was connected to the calcium chloride brine line of a fish freezer at Manasquan, N. J., and the outlet pipe delivered the brine to a storage tank above, whence it reentered the system to be recooled. The calcium chloride brine of the fish freezer a t this time was being maintained a t temperatures below -15" F. The salt brine in which the fish were frozen was made up of desired strength in the tank with the assistance of a hydrometer. FREEZING OF FISH-Small quantities of fish were lowered into the cold brine and held beneath the surface by means of suitable weights. By constantly adjusting the valves and agitating the solution the freezing medium was kept a t constant temperature. Some lots of fish were precooled in air to about 32' F. before freezing, while others were placed in the brine without previous chilling. All fish immediately after removal from the solution were dipped momentarily in cold fresh water to remove surface brine. ANALYSES OF FISH. Sampling-The fish were sampled while hard frozen. A section approximating a cylindrical quadrant in shape was cut from the mid-dorsal region. The skin of this section, after careful separation from the muscular tissue, was scraped to remove scales, and was then cut into fine pieces, divided into two portions, and placed in tared weighing bottles. From the piece of muscular tissue remaining two successive slices of known thickness were cut on the side which had been next to the skin. The slices were chopped into small pieces and transferred to tared weighing bottles. The samples, therefore, consisted of the skin (without scales) and frrst and second muscular layers. Solids-Total solids were determined in a number of the
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T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEiWSTRY
Vol. 13, No. 10
samples by drying the material to constant weight in tared Weakfish, flounders, and whiting were frozen in sodium chloride solutions of different concentrations a t their freezing porcelain dishes in a vacuum oven at 55" to 60" F. Ash-The organic matter in the sample, after drying, was points and at several degrees above these temperatures. I n driven off in an electric muffle at temperatures below 750" F. the former instances the presence of ice crystals in the freezing media was taken as an indication that the brine solutions The dish and contents were then weighed. Sodium Chloride-The ash residue in the porcelain dish were at the desired temperatures. The figures given in was treated with about 30 cc. of hot water, and allowed to Table I indicate that salt penetration occurs under all concool. The solution was titrated with 0.1 N silver nitrate, ditions. The amounts of penetrated salt in the first and second muscular layers of fish frozen in 25 per cent brine at using potassium chromate as an indicator. Fat-The percentage of fat was determined in representa- 6" F. and 12"I?. were greater than they werein fish frozen in tive samples of the entire flesh of some of the fish in the usual the same brine a t 0" F. Also, in the case of the whiting manner'4 by extracting the water-free solids from about 10 g. frozen in 15 per cent brine, the higher temperature appeared of flesh with anhydrous alcohol-free ether for 16 hrs. to be more favorable for salt penetration. In the majority of cases, however, the degree of the penetration is not markedly RESULTSOF EXPERIMENTS The conditions to which the fish were subjected in these influenced by the temperature factor. In most of these experimentsthe temperature of the fish upon experiments were intended to cover nearly every type which might be encountered in the commercial freezing of fish in entering the brine was 60"F. to 70 " F. Hence the difference chilled brine. Penetration of salt into the skin and outer in temperature between the fish and the various brines when muscular tissue of the fish occurred in every instance, al- at the lower temperatures was 48" F. to 70"F. The entrance though many of the experiments were designed with a view into the cold brine of one or more such fish cannot fail to to preventing the entrance of salt. The amount of salt have some effect upon the temperature of the brine in immeentering was not sufficient in any case to affect the flavor of diate contact with the fish. This slight rise in temperature the fish after cooking. The percentage of penetrated salt in has the effect of retarding the process of freezing the outer the outer layer of muscular tissue one-eighth inch in thick- surface of the fish. Therefore, appreciahle salt enters the ness was found to be from 0.32 to 6.22 per cent (dry basis) skin and the superficial muscular layer before the surface of in the case of all fish so examined, the average being 2.88 the fish has congealed. It thus appears that, from the standpoint of the penetration of salt into fish, very little advantage per cent. The salt used throughout the investigation was of the is gained by endeavoring to keep the brine solution a t thegrade which is known as Ground Alum salt. It contained freezing point when the temperature of the product to be approximately 98-80 per cent NaC1, 0.90 per cent CaS04, frozen is appreciably higher than that of the brine. 0.06 per cent CaC12,and 0.003 per cent MgC12.15 TABLE 11-EFFECT O F CONCENTRATION OF BRINE ON SALT PENETRATION EFFECT OF BRINE CONCENTRATION AND TEMPERATURE-AS is well known, salts dissolved in water cause a lowering of the freezing point of the solvent. The point a t whichice begins to separate out under favorable conditions is a definite 1st 2nd Mus. Musfunction of the concentration of the solute. If the temperacular cnlar ture of an aqueous solution be maintained a t its freezing ExP?.. Skin Layer Layer No. FISH 'F. 3'6 * B. Hrs. In. Percent Percent Percent point while water is being added to it, theoretically ice 6021 Weakfish 60-70 15 12 2 0.125 3.31 2.47 0.83 crystals should form, since the diluted solution would then 6010 60-70 20 12 2 0.125 1.87 0.67 0 . 6 0 0.125 1.90 0.32 0.36 6010 60-70 20 12 2 be under its freezing point. 6025 Flounders 60-70 15 12 2 0.125 3.82 2 . 7 6 0.42 It is this property of solutions of which use is made in one 6011 60-70 20 12 2 0.125 4.15 3.28 0 . 8 1 31 1 8 . 9 12 1 0.09375 ... 2.28 2.40 0.91 6046 Whiting of the brine freezing processes.16 The concentrations and 31 15 12 1 0.09375 ... 1.33 6047 temperatures of the brine solutions are so adjusted that the solutions remain constant a t or slightly under their freezing I n the experiments reported in Table I1 an effort was made points during the entire freezing process. It is claimed that to determine the effect upon the degree of salt penetration under these conditions penetration of salt into the tissues of produced solely by variations in the concentration of the the products frozen is prevented, making possible a "strictly ' brine. The amount of penetrated salt was slightly greater indifferent and purely physical conservation of food com- in the first muscular layer but less in the second in the case modities." of whiting frozen in 18.9 per cent brine than it was in those TABLE I-ERFECT OF BRINETEMPSRATUR~ ON SALT PENETRATION frozen in 15 per cent brine, both being at 12" F. Flounders frozen in 20 per cent brine a t 12" F. absorbed more salt in Penetrated Sodium Chloride (Moisture-Free both muscular layers than did those frozen in 15 per cent Basis) a t the same temperature. A corresponding increase in salt 1st 2nd Mus- Muspenetration with increase in brine concentration did not cular cular ocrur in the weakfish examined. A consistent relationship Skin Layer Layer EXPT. Frsn OF. % IIrs. In. Per cent Per cent Per cent No. between salt penetration and brine concentration is not in6002 Weakfish 60-70 15 12 3 0,125 3.98 2.33 0.67 dicated by these experiments. 6008 60-70 15 17 3 0.125 6.06 2.43 0.49 6008 60-70 15 17 3 0.120 3.15 0.42 0.36 RATE O F SALT PENETRATION-weakfish, flounders, herring, 6004 60-70 20 6 2 0.125 1.34 0.57 0.52 0 . 5 0 0.63 6004 613-70 20 6 2 0.125 2.50 and whiting, as indicated in Table 111, were immersed for 6010 60-70 20 12 2 0.125 1.87 0.67 0.60 30,60,90 and 120 rnin in 15 per cent brine a t 12 " F. Exami0.125 1.90 0.32 0 . 3 6 6010 60-70 20 12 2 0 1 . 5 0.125 14.12 2 . 5 1 0 . 5 9 6012 60-70 25 nation of the skin and outer muscular layers revealed the 6012 60-70 25 0 1 . 5 0.125 9.05 3.45 0.35 6014 60-70 25 6 1 . 5 0.125 7.26 3 . 9 0 0.86 fact that in the case of weakfish and flounders the greater 6014 60-70 2.5 6 1.5 0.125 6.49 6.62 1.69 6015 60-70 25 12 1 . 5 0.125 9.50 4.71 1.85 part of the salt penetration occurred during the first 30 min. 6015 00-70 25 12 1 . 5 0,125 5.59 3 . 8 1 1.78 of the freezing. I n the herring and whiting the absorption 6030 Flounders 60-70 15 12 1 0,125 ... 4.84 5.01 .,. 6031 60-70 15 17 1 0.125 ... of salt continued throughout the 2 hrs. in which the fish 6013 60-70 29 0 1 . 5 0,125 6.99 2.37 0:2S were under observation. The results indicate that the rate 6016 60-70 20 6 1 . 5 0.125 6.23 5.57 1 . 3 1 6017 60-70 25 12 1 . 5 0.125 9.70 1.56 0.69 and amount of salt absorption varies with the species of fish, 6044 Whiting 31 15 17 1 0.09375 ... 2 . 8 0 1.43 a subject which will be discussed in another section. 6047 31 15 12 1 0,09375 .. . 2.28 1.33 O F .
TABLE111-RATE O F SALT PENETRATION (15 Per cent Brine at 1Z0 F . )
EXPT. NO.
6018 6018 601s 6018 8040 6040 6040 8040 8022 6022 6022 6022 6041 6041 6041 6041 6042 6042 6042 6042
FISH Weakfish
Flounders
Herring
Whitinn
F. 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 60-70 fi0-70 60-70 60-70
Min. 30 60
90 120 30 60 90 120 30 60 90 120 30 60 90 120 30 60 90 120
Penetrated Sodium Chloride (MoirtureFree Basis) 1st 2nd Mus- Muscular cular Skin Layer Layer In. E'er cent Per cent Per cent 0.126 3.88 2.46 0 . 5 4 0.i25 3.38 2.27 0.57 0.125 4.46 3.13 1.35 0.125 3.31 2.47 0.83 0.09375 4.72 2.32 0.92 0.09375 6.53 2.49 1.09 0.09375 6.52 3.25 1.18 0.09375 7.88 1.70 0.75 0.125 4.40 4.11 0.59 0.126 4.91 3.53 0.29 0.125 6.40 3.82 0.66 0.125 3.82 2.75 0.42 0.09375 5.39 0.14 0.02 0.09375 3.90 0.50 0.06 0.09375 4.99 0.57 0.09 0.09375 3.75 1.04 0.41 0.09375 4.06 2.28 1.13 0.09375 4.31 3.05 1.45 0.09375 5.36 4.39 1.98 0.09375 5.79 5.44 2.45
The weakfish and flounders differed from the other two species of fish in another respect. There occurred a falling off in the per cent of salt in the first and second muscular layers after the former had remained for 90 min. in the brine. A plausible explanation of the phenomenon is that in the first few minutes during the immersion of the fish in the brine the rate of penetration of salt into the skin and outer muscular layer is faster than the speed of diffusion of this salt to the inner layers and that later the salt travels inward with greater speed than it is being replenished from without, the frozen exterior of the fish greatly retarding salt penetration. If the above expresses the true condition, then it must also be admitted that salt will tend to spread itself uniformly through the entire flesh of the fish, by diffusion inward, even after the tissues have become hard frozen. That this mode of action is probable is indicated by the fact that when a block of ice is immersed for 2 hrs. in chilled brine a t its freezing point, salt will enter the ice and will proceed inward toward the center of the block after removal from the brine and while standing in air a t the same temperature as the brine. The latter observation was made in connection with some experiments which were performed on the absorption of salt by ice, the results of which will be made the subject of a separate communication. TABLEIV-EPFECT OB PRECOOLING ON SALTPENETRATION
of that occurring in those which were not precooled. In the practical operation of a plant, the chilling of the fish prior to freezing in this manner would necessitate a slight delay in completing the freezing process and would add somewhat to the cost of freezing the fish. I n view of the fact that absorption of salt occurs in spite of this precaution, it would seem that such a procedure would hardly be justified from that point of view alone. These remarks apply only to freshly caught fish, as it is assumed that fish which have been out of the water for some time have been kept cold by one means or another and would, therefore, not require further precooling before treatment. SALT PENETRATION AS A SPECIES CHARACTERISTIC-on examination of the figures in Tables I, 11, 111, and I V it will be noted that in several instances the amount of sodium chloride absorbed by the tissues varied in the same species even when all conditions, which could be controlled, were identical. These irregularities were due, i t is believed, in part to differences in the composition of the outer muscular and cutaneous layers of the fish and in lesser degree to slight inequalities in the physical condition of the fish brought about in the handling prior to immersion in the brine. Although great care, was exercised to prevent a bruising of the fish, it is possible that some of them may have received slight wounds which, though not visible to the naked eye, may have been effective in altering the resistance of the outer tissues to invasion by foreign material. TABLEV-SALT PENETRATION AS A SPECIES CHARACTERISTIC
e"
1;
EXPT. No. 6019 6023 6030 6041 6040 6042
FISH Weakfish Flounder Flounder Herring Weakfish Whiting
80-70 34 34 60-70 34 56 31
12 12 12 17 17 12 12
lk 15 15 15 15 15 15
1 1 1 1 1 1 1
0.125 0.125 0.125 0.125 0.125 0.09375 0.09375
4.98 1.87 1.31 5.17 2.69 3.50 2.28
FISH-Inasmuch as the penetration of salt is greatly retarded after the surface of the fish has become hard frozen, it is obvious that it might prove of advantage to precool fish before immersing them in the brine in order to hasten the freezing process and thus reduce the amount of salt absorption. The effect of such a procedure is illustrated by the figures in Table IV, showing the per cent of salt in the first muscular layer of weakfish and whiting, some of which were precooled to 31" or 34" F., and others of which were a t temperatures between 50" and 70" F. just prior to immersion in the brine. There was considerably less absorption in the case of the precooled fish, the amount being 35 to 66 per cent PRECOOLED
....
Aside from the individual variation in the same species, there appear to be marked species differences in the amount (Table V) and rate (Table 111) of salt penetration. Arranging the fish in series, beginning with the species which absorbs the most salt and ending with the one which offers the most resistance to salt penetration, they assume the following order: whiting, flounder, weakfish, and herring. Mention has been made of the differences in the rate of salt penetration exhibited by weakfish and flounders on the one hand and whiting and herring on the other. TABLEVI-DATA
6028 Weakfish 6032 6036 6029 6033 6048 Whiting 6047
OF. Hrs. 60-70 60-70 60-70 60-70 60-70 80-70
Penetrated Sodium Chloride (MoistureFree Basis) 1st 2nd MUS- MUScular cular Skin Layer Layer In. I'er cent Per cent Per cent 3.38 2.27 0.57 0.125 4.91 3.53 0.29 0.125 5.01 0.125 0.09375 i : $ b 1.04 0.41 0.09375 7.88 1.70 0.75 0.09375 6.79 5.44 2.45
CONCERNING THE DISTRIBUTION OF FAT IN EXPSRIMENTAL FISH ON DRY BASIS
Skin EXPT. No. FISR .. 679 Whiting 676 Flounder 677 Weakfish 678 Herring
Gram 0.0407 0.0743 0 0769 010627
Scales Gram Percent 0.0391 (3) 3 86 1) 0.0704 (4) 5 : 36 12) 0 0366 (2) 52 56 (4) 0:0346 (1) 44:79 (3)
Fat-Subcutaneous Body Tissue Tissue Percent Percent 4.74 (1) 0.52( I ) 11 .16(2) 1.04 (2) 59.10 3) 10.37(3) 63.4814) 14.36 (4)
The analyses reported in Table VI were made in an effort to determine the causes responsible for these species differences. Comparisons were made of the dry fat-free weights of equal areas of scale-free skin and the per cent of fat in the skin, subcutaneous tissue and main body tissue of whiting, flounders, weakfish, and herring. If the numbers in each of the last four columns in this table are arranged in sequence of increasing values they will fall in the order indicated by the figures in parentheses opposite each number. It is seen
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T H E JOURNAL OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
that the order in which the fish fall on the basis of the f a t content of the subcutaneous and body tissue is the same as that which they assume when arranged according to their increasing resistance to salt penetration. It therefore appears that the presence of fat in these tissues tends to retard the entrance of salt. The latter substance in aqueous solution will penetrate fat-poor tissue with greater speed than it will the fat-rich tissue, partly because the amount of moisture in fatty flesh is less than it is in lean and partly on account of the mechanical retarding action of the solid fat in the chilled tissues. Variations in the proportions of subcutaneous fat would have a greater effect upon the extent of salt penetration than would differences in the per cent of body fat, as the proportion of water accompanying the former is much less than that associated with the latter and the adipose tissue is also more favorably situated to retard the entrance of the salt. While the differences in the fat content of the superficial body tissues of the fish offer an explanation for the species variations in the amount of salt which penetrates in equal periods of time, they do not explain why herring and whiting differ markedly from weakfish and flounders in the rate of salt penetration. In the absence of evidence to the contrary it would seem that differences in skin and muscle structure might well account for the latter phenomenon.
SUMMARY Weakfish (Cynoscioa regalis), flounders (Pseudopleuronectes americanus), herring (Clupea harengws), and whiting (Merluccius bilinearis) were frozen in chilled brine under different conditions to determine the various factors which influence the penetration of salt into the outer tissues of the fish. To assist in the determipation of the degree of salt penetration, the skin and two successive layers of muscular tissue just beneath the skin were analyzed for their content of penetrated salt. The muscular layers examined were usually one-eighth of an inch in depth, a few being threethirtyseconds of an inch thick. It was found that: 1-Salt penetrated perceptibly into the skin and superficial muscular tissues of all the fish under all conditions, the amount not being sufficient, however, to affect the taste of the cooked product. 2-During the process of freezing the above species of fish under various conditions, the outer muscular layer oneeighth inch in depth absorbed from 0.32 to 6.22 per cent of salt on the dry basis, the average being 2.88 per cent. 3-In a few instances the amount of salt absorbed by fish frozen in brine a t its freezing point was slightly less than that which occurred when the brine temperature was several de-~ Pees above this point. In the majority of cases, however, no such temperature influence could be observed. & - w h e n fish were frozen in brines Of different tions but a t the same temperature, no Consistent differences in the amount of salt absorbed by the fish could be noted. S-Fish which had been precooled to near 320 F. before immersion in the brine did not take Up as much Salt as those which were a t atmospheric temperature a t this time, the absorption in the former case being 35 to 65 per cent of that in the latter. 6-The amount and rate of penetration of salt into the tissues of fish varies with the species. In weaMish and flounders the greater part of the salt which can be found in the superficial tissues a t the end of a 2-hr. immersion in brine entered during the &st 30 min. The absorption in the case of whiting and herring was more gradual, continuing rather uniformly during the two hours. 7-Inequalities in the fat content of the subcutaneous and body tissue of the fish are responsible in large measure for
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the differences in the susceptibility to salt penetration possessed by fish of the same species and by those of different species.
REFERENCES I-“The Commercial Freezing and Storing of Fish,” U. S. Department of Agriculture, Bulletin 686; E. D . Clark and I ,. H. Almy, “A Chemical Study of Frozen Fish in Storage for Short and Long Periods,’ THIS JOURNAL, i a (19201, 656. 2-J. R. Henderson: U. S. Patent 1,055,636 (1913). 3-A. J. A. Ottesen: U. S. Patent 1,129,716 (1915); Fish Trades Gazette, October 20, 1917, 39, 41, 43. 4-N. Dahl: U. S Patents 1,123,701 (1915), 1,177,308 (1916),1,235,661 (1917), 1,367,024 (1921); H. J. Bull, U. S. Patent 1,201,552 (1916). &J. S. Gardiner and G. H. F. Nuttall: “Frozen Fish. Dry Freezing -Brine Freezing,” Fish Trades Gazette, January 19, 1918, 23, 25. +Cold Sforage and Produce Review, 22 (1919), 173. 7-Ibid., 28 (1920), 227. 8-Ice and Refrigevalion, 49 (19151, 333. *The Frigus System, developed b y N. Dahl, has been operated with profit at Throndhjem, Norway, for a number of years. 10-J. M. Bottemaine: “Notes on the Investigation of Preserving Fish b y Artificial Cold.” Preliminary Report, 3rd International Congress of Refrigeration, 3rd Section (The Netherlands). Washington-Chicago, 19lS,27. 11-R. Plank, E. Ehrenbaum and K. Reuter: “Die Ronservierung von Fischen durch das Gefrierverfahren,” Abhandlungen zur Volksernahrung, issued b y the Zentral-Einkaufsgesellschaft, 6 (ISIS), 218. 12-“Interim Report on Methods of Freezing Fish, with Special Reference to the Handling of Large Quantities in Gluts,” Fish Preservation Committee, Food Investigation Board, Department of Scientific and Industria! Research, London, England (1920). I3-Plank, el al., LOC.cil , 5 2 4 2 . 14-Association of Official Agricultural Chemists, “Methods of Analysis,” 1916, 80. 1.5-Plans for determining the effect upon salt penetration produced by additions of calcium salts to the brine solution had t o be abandoned when the chemical laboratory equipment a t Philadelphia was”dismantled on the occasion of the removal of the headquarters of the Food Research Laboratory to Indianapolis, Ind. 16-A. J. A. Ottesen: LOC.cil.
Labeling of Vinegar The question as to the legal labeling of vinegar made from evaporated apples under the Federal Food and Drugs Act, which has been under controversy for some time, is to be litigated in the Federal Courts, according to a statement just issued by the Secretary of Agriculture. In February 1912, the Department of Agriculture in Food Inspection Decision 140 defined vinegar, cider vinegar, and apple vinegar as the product made from the alcoholic and subsequent acetous fermentations of the expressed juice of apples. This decision further provided that “the product made from dried apple skins, cores, and chops by the process of soaking with subsequent alcoholic and acetous fermentations of the solution thus obtained is not entitled to be called vinegar without further designation, but must be plainly marked to show the material from which it is Droduced.” Upon finding in the mark& vinegar made from evaporated apples but labeled as cider vinegar, the Department made a number of seizures. Some of the manufacturers elected to contest these cases in court, but the termination of such litigation has been delayed. In the effort to reach a satisfactory settlement of the question the Secretary of Agriculture, under date of July 14, 1921, called a public hearing and invited representatives of the industry, food law officials, and all interested parties to submit their views. The hearing was attended bv a numbelof vinegar manufacturers, and letters were received -from many state officials charged with the enforcement of food laws, and it was evident that the tentative suggestion of the Department that the term “apple vinegar” be permitted for vinegar made from evaporated apples is unsatisfactory to some of the manufacturers of such vinegar and to some of the manufacturers of vinegar from apple juice, as well as to many state food officials. The manufacturers of vinegar from evaporated apple stock claim that as their vinegar is made wholly from apples and apple products they have a right to use the descriptive terms “cider vinegar” and “apple cider vinegar,” while the manufacturers of vinegar from fresh apple juice insist that Food Inspection Decision 140 be strictly adhered to. Pending the expected prompt decision of the court, no seizures will be made of vinegar made from evaporated apple stock and labeled “apple vinegar.”
