MFR PAPER 1185

Nitrite Additives- Harmful or Necessary?

ELINOR M. RAVESI

INTRODUCTION 1971; Sen, 1972; Fazio et aI., 1973; nitrite (Epstein), 1971; Hill·, 1971; Panalaks, Iyengar, and Sen, 1973; Sander and Schweinsberg 5, 1971; Can­ The use of nitrites in the preparation Panalaks et aI., 1974), cured fishery toni, Renon, and L'Acqua, 1974; of smoke-cured fishery products and products (Ender and Ceh, 1968; Sen et Myslivy et aI., 1974). Nitrosamines processed meat products dates back to aI., 1970; Fazio, Damico, Howard, have been isolated from gastric juices 1925. Prior to that, dating back to the White, and Watts, 1971; Sen et aI., of animals fed these precursors and early beginnings of the curing process, 1972; Kawabata et aI., 1973; Gadbois et under simulated human stomach con­ nitrates, usually containing nitrite aI., 1975), in addition to other products ditions (Walters, Saxby, and Newton 6, impurities, were used. Nitrites are such as cheese (Sen, Smith, Schwing­ 1971; Lane, Rice, and Bailey, 1974). used in the curing of meats to impart hamer, and Marleau, 1969), soybean oil The presence of several amines such red color, to enhance flavor, and to (Hedler et al:, 1971), milk (Hedler and as methylamine, di- and trimethyla­ protect the product from the growth of Marquardt, 1968), alcoholic beverages mine, di- and triethylamine, N-propy­ Clostridium botulinum in case of con­ (McGlashan, Walters, and McLean, lamine, and N-butylamine has been 1968), and tobacco (Hoffman et aI., tamination or mishandling. In the 1974). They have also been found to reported in a variety of fishery curing of fishery products, the addition occur in vivo. For a variety of animals products (Gruger, 1972). Their occur­ of sodium nitrite (NaNOz) prior to tested in feeding studies, many of rence, primarily a result of bacterial smoking to inhibit the growth of C. these compounds have been shown to and enzymic action, is known to vary botuUnum, thereby preventing for­ be highly potent carcinogens (Preuss­ considerably, quantitatively and quali­ mation of its toxin, is of primary mannz, 1971; Swann and Magee, 1971; tatively, depending on such factors as importance. In recent years, the use of and Preussmann, 1974). The danger of the species and the age of the fish, as nitrites has been viewed with suspicion, these N-nitroso-compounds to human well as storage and handling con­ beings has not yet been established, as and the continued use of NaNOz in the ditions. They may also arise during food industry has become a matter of there is no direct evidence of their cooking. Freshwater species of fish of controversy. The questions arising carcinogenicity in man. Although much remains to be learned concerning the from the use of nitrites are: 1) Is their 'Epstein. S. S. 1971. In vivo studies on continued use necessary for the pro­ chemistry of these compounds, they interactions between secondary amines and are known to form in foods and in the nitrites or nitrates. Presented at the Inter­ duction of a product safe from deadly national Agency for Research on Cancer and various organs of animals under the Deutshes Krebsforshungszentrum Joint bacterial toxin? 2) Is their presence Meeting on the Analysis and Formation of responsible for the occurrence and favorable conditions of pH, time, and Nitrosamines. temperature from the reaction of • Hill, M. J. 1971. Bacterial production of formation of highly potent carcinogens nitrosamines in vitro and in vivo. Presented at in foodstuffs and/or in the bodies of the secondary and tertiary amines with the I nternational Agency for Research on Cancer and the Deutshes Krebsforshungszen­ consumers of these foodstuffs? trum Joint Meeting on the Analysis and Formation of Nitrosamines. In recent years, the occurrence of 'Hedler, L., H. Kaunitz, P. Marquardt, H. ' Sander, J., and F. Schweinsberg. 1971. trace amounts of N-nitrosamines has Fales. and R. E . Johnson. 1971. Detection of In -v ivo and in-vitro experiments on the N-nitrosocompounds by gas chromatography formation of nitrosocompounds from amines been indicated in many cured meat (nitrogen detector) in soybean oil extract. and amides and nitrate on nitrite. Presented at products (Fazio, White, and Howard, Presented at the International Agency for the International Agency for Research on Research on Cancer and the Deutshes Krebs­ Cancer and the Deutshes Krebsforshungszen­ forshungszentrum Joint Meeting on the trum Joint Meeting on the Analysis and Analysis and Formation of Nitrosamines. Formation of Nitrosamines. Elinor M. Ravesi is a research 'Preussmann, R. 1971. On the significance of • Walters, C. L., M. J. Saxby, and B. E. chemist with the Northeast Utiliza­ N -nitrosocompounds as carcinogens and on Newton. 1971. Nitrosation under simulated tion Research Center, National problems related to their chemical analysis. stomach conditions. Presented at the Inter­ Presented at the International Agency for national Agency for Research on Cancer and Marine Fisheries Service, NOAA, Research on Cancer and the Deutshes Krebs­ the Deutshes Krebsforshungszentrum Joint Emerson Avenue, P.O. Box 61 , forshungszentrum Joint Meeting on the Meeting on the Analysis and Formation of Gloucester, MA 01930. Analysis and Formation of Nitrosamines. Nitrosamines.

24 the Great Lakes region, often used in approving such uses, and establishing test animals which had been simul­ the preparation of smoked fishery safe limits referred to in the law as taneously fed nitrites and certain products, have higher amine contents "tolerance limitations." secondary amines. Malignant tumors than do marine fishes. If it is proven A significant feature of the Food were produced in rats by a dose as low that the simultaneous consumption of Additives Amendment is the Delaney as 2 ppm of diethylnitrosamine (Com­ these amines and nitrites present a real Clause which is intended to protect the mittee on Government Operations, hazard to our health, then all possible consumer from the potential hazards of 1972). To date, a "no-effect level" has steps must be taken to eliminate this ingesting carcinogenic chemicals. FDA not been established for this com­ hazard. By no means would it be is prohibited by this clause from pound. A German study (Sander and possible for us to eliminate these amine approving the use of any food additive Seif, 1969), in which nitrate and the compounds from the foods we eat. We which has been found to induce cancer secondary amine diphenylamine were can, however, to some extent, control when consumed by man or animal. fed concurrently to human volunteers, the amount of nitrite we consume-at FDA may approve a proposed use of an demonstrated that both nitrosation and least that amount which is not a additive after evaluating the data the reduction of nitrate to nitrite were naturally occurring constituent of food. submitted to it and finding that there is occurring in the human body. For­ The U.S. Food and Drug Admin­ no doubt that the proposed use would mation of nitrosamines in human istration (FDA) has issued regulations accomplish the "intended physical or gastric juices due to ingestion of on the safe use of NaN0 2 for the other technical effect," that is, the precursors has also been demonstrated preservation of smoked fishery pro­ effect the additive may have on the by other investigators (Sen, Smith, ducts. As early as 1925, the U.S. sensory or other aspects of the food. and Schwinghamer, 1969; and Magee, Department of Agriculture (USDA) The task of the FDA, in its considera­ 1971). In no instance, however, was imposed an upper limit of 200 ppm tion of whether the additive produces carcinogenesis established. residual sodium nitrite in any cured the desired effect and how much of the Nitrates and nitrites received USDA meat or fish product as it was known additive is required to produce the approval for use in the curing of meats since the early part of this century that intended effect, does not include years before passage of the Food high doses of sodium nitrite had a toxic judging whether the effect increases Additives Amendment and were, effect on humans causing methemo­ the value of the product to the therefore, exempt from its provisions globinemia, the result of nitrite com­ consumer or improves its marketa­ because of "prior sanctions." However, bining with the hemogloblin of blood. bility. Significantly, the amendment prior sanctions may be revoked and Public concern and pressure for does not delegate to the FDA the regulatory action taken against the use stronger and more effective food and authority to balance the benefits of a of nitrates and nitrites. For food other drug control laws resulted in the enact­ food additive against the risks as­ than meats, no such prior sanction ment of the Federal Food, Drug, and sociated with its use in deciding exists, and the use of nitrates and Cosmetic Act of 25 June 1938. This whether to approve the use. The FDA nitrites in such foods must be pre­ legislation increased regulatory control is expected only to consider whether cleared and approved for use by FDA. over toxic s\lbstances added to food; the additive produces the intended The Delaney Clause prohibits FDA but as the use of new food additives effect and whether it is safe for human from approving any food additive "if it mushroomed, it became apparent that consumption. is found to induce cancer when ingested this law, too, was inadequate. In 1958, In January 1971, the Intergovern­ by man or animal." Application of this as a result of a study conducted by the mental Relations Subcommittee began clause to the nitrite situation is compli­ Congressional Delaney Committee, the an investigation to determine the cated by the fact that nitrites per se Food Additives Amendment of 1958 adequacy of the protection being have not been found to produce cancer was passed. This amendment required afforded consumers by the FDA and but rather when ingested simul­ FDA preclearance of all new food the USDA against potentially harmful taneously with certain secondary and additives for safety before marketing. food additives. The investigation was tertiary amines have produced cancer Prior to the passage of this amend­ undertaken because of widespread in animals. It would appear then that ment, when adulteration of food was public concern about the potential the Delaney Clause is technically and charged, FDA was legally obliged to dangers of food additives. In March of legally not applicable to nitrites if a prove that the substance was that year, hearings focused on addi­ reaction takes place between nitrites poisonous; that it had been added; and tives of current scientific concern such and secondary amines in a man's that it was unnecessary in the pro­ as nitrites and nitrates because of their stomach but does become applicable if duction of the food. The Food Additives possible conversion in food or in the it can be demonstrated that nitro­ Amendment changed this situation. It body to cancer-producing nitrosamines samines are produced in the meat or shifted the burden of proof from FDA and nitrosamides making them a fish from the added nitrite and these to the manufacturer, distributor, or potentially serious health hazard. To nitrosamines are consumed. user of a new food additive who was date, there is no conclusive evidence The discovery prior to 1925 that required to prove its safety. Under the that nitrosation, the formation of nitrites would more efficiently produce amendment, FDA is responsible for nitrosamines from their precursors, in the intended effect, namely color determining the safety of all food the human stomach causes cancer; fixation and enhancement in meat, led additive uses, publishing regulations, however, cancer has been produced in to the petition of USDA by several

25 meat establishments to experiment Laboratory has done considerable it is found that the nitrites are being with the use of nitrites. As a result of research in the area of nitrosamine added not as a preservative but only to these experiments, the limit or occurrence and detection. He is critical fix color, then it apears unquestionable tolerance of 200 ppm of nitrite was set. of the present use of nitrites stating that their use should be prohibited. If, This limit was based on the maximum that the permitted level of 200 ppm of on the other hand, levels of nitrite can nitrite content found in the cured nitrite leaves no margin of safety. be established which cause no nitrosa­ meats produced during these experi­ Lijinsky has not called for a ban on the mines to be formed in the product, then ments, and it in no way pertains to the use of nitrites in the curing process but the use of nitrites should not be prohib­ minimum quantity necessary to accom­ rather urges that the permitted levels ited by a sweeping generalization; plish the intended effect. There is no of residual nitrite be brought into line i.e., assuming it can be shown that justification whatsoever for this limit. by carefully determined needs rather there is no significant formation of ni­ A most important question to be than to be set by an arbitrarily chosen trosamines in the stomach after inges­ answered then is how much nitrite is amount. If the amount of residual tion of these nitrites. The FDA ini­ actually needed to accomplish its nitrite varies so considerably in a tiated formal action in November 1972, purpose. As little as 10 ppm of nitrite, finished product and if the amount is so to ban the unnecessary and hazardous for example, suffices to impart accept­ often found below 50 ppm and found to use of nitrites, an action which would able flavor and color to bacon; however, be effective at these low concen· seriously affect the smoked fish indus­ from a bacteriological viewpoint, this trations, why then can't lower limits be try. If finalized, this action would put a level may be inadequate. established and enforced? stop to the use of sodium nitrite in In view of the findings of the sub­ More than 6,500 samples of nitrite­ smoked-cured sablefish, salmon, and committee, the evidence that nitrites treated meat were tested by the USDA shad, sodium nitrite in smoked tuna play an important role in preventing during the period 1 January 1970, to 31 fish products, and potassium nitrite in the occurrence of botulinum poisoning January 1971. More than 79 percent of cod roe. Allegedly, the additives in in meats is not exceptionally strong these samples were found to have 25 these instances are being added pri­ except in special cases such as the ppm or less, and 92 percent contained marily as preservatives. larger-sized canned hams. The 3- and 50 ppm or less. Actually, the problem Following the passage of the Food 5-lb cans may require the addition of of how much nitrite is needed in the Additives Amendment of 1958, the nitrite because the heat penetration curing of a product and the determi­ FDA imposed regulations pertaining to necessary to destroy botulinum spores nation of the residual nitrite that the use of nitrate and nitrite in smoked in meat may be difficult to achieve. remains in the product after curing and and cured fish products. The following A summary (Center for Disease storage are complicated , to say the regulations (Committee on Govern­ Control, 1974) of botulism outbreaks least. Residual nitrite is only that ment Operations, 1972) were pub­ during the period 1899-1975 revealed amount of nitrite which can be detected lished. only 11 (possibly 10) instances in which by current analytical techniques. It is a meat was the cause of botulinum 1) Regulations 21 CFR 121.1063 superficial description and in no way and 121.1064 which permit the use poisoning. Beef was the vehicle in four explains what became of the nitrite of sodium nitrate and sodium nitrite outbreaks (in one outbreak, traced to which was incorporated into the pro­ in amounts not to exceed 500 parts beef stew, the actual source is duct at the time of curing but which, per million of nitrate and 200 parts unknown), pork in three, poultry in during storage, "disappeared." A per million of nitrite in smoked and cured salmon, sablefish, and shad, three, mutton in one, and venison in number of reaction pathways have and in home-cured meat, poultry one. All of these were caused by types been well established for the removal and game, primarily for color fixa­ A and B toxins with the exception of of free nitrite in meat products tion and secondarily for preser­ the venison-caused outbreak which (Cassens et aI., 1974); however, total vation. was traced to the rare type F. There losses still can't be accounted for. To be 2) Regulation 21 CFR 121.1132 permits the use of potassium nitrate has never been any reported instance concerned with the free nitrite which as a curing agent In the processing of botulism attributable to fresh meat. might combine with amines to form of cod roe in an amount not to Here the potential might seem to exist nitrosamines is to be concerned with exceed 200 parts per million of the since beef is often aged at controlled only a portion of the problem. What, finished roe. 3) Regulation 21 CFR 121.223 temperatures for varying periods of for example, is the "Perigo inhibitor" permitting the use of sodium nitrite time before cooking or curing. (Perigo, Whiting, and Bashford, 1967)? as a preservative and color fixative However, most meats are cooked prior This unknown inhibitor for the growth in canned pet food containing fish to consumption destroying the of several species of Clostridium has and meat provided that the level of sodium nitrite does not exceed 20 botulium toxin and ensuring the safety been found to form when certain parts per million. of the food. The toxin is easily culture media are heated in the 4) Regulation 21 CFR 121.1064 destroyed by heat, therefore any meat presence of NaNOz, and its inhibitory permitting the use of sodium nitrite which must be cooked cannot present a activity differs from that of nitrite as a preservative and color fixative hazard to the consumer. Bacon, then, alone. in smoked and cured tuna fish products, provided that the level of would be considered a typical example. If nitrites are being used with sodium nitrite does not exceed ten William Lijinsky of the Carcino­ concomitant formation of nitrosamines parts per million in the finished genesis Program at Oak Ridge National when no danger of botulism exists or if product. 26 5) Regulation 21 CFR 121.1230 and it is these violators who are strain had not yet been identified. permitting the use of sodium nitrite exacerbating the problems in the use of However in 1935, type E was isolated in processing smoked chubs to aid in nitrite additives for the conscientious from Russian sturgeon and was found inhibiting the outgrowth of toxin formation from Clostridium botuli­ processor of smoked fish. Violations to be identical to that strain isolated num type E, provided that the become more common with insufficient from the salmon of the 1932 outbreak sodium nitrite content of the edible monitoring and laxity in regulatory and also from some imported German portion of the finished smoked action. Though the maximum per­ canned sprats which were the cause of product is not less than 100 parts per million and not greater than 200 mitted tolerance for sodium nitrite is a second outbreak in 1934. parts per million as measured in the 200 ppm in smoked and cured fish, It was in the early sixties that loin muscle. FDA has established 260 ppm as the attention was focused on the smoked, Regulation (5) went into effect in action level for smoked chub. That is, freshwater fish of the Great Lakes August 1969. Before that date, chubs seizure or other action involving region. The first known cases of were prepared without the use of smoked chub containing excess sodium botulism caused by fish caught in the nitrites because it use was not per­ nitrite will not be authorized unless the Great Lakes were reported in 1960 mitted. However, after three out­ level is at least 260 ppm. The 1970 when commercially-processed, va­ breaks of botulism which were attri­ survey also revealed smoked chub cuum-packed, smoked ciscoes were buted to smoked chubs and which samples with nitrite levels far below found to be the cause of an outbreak in caused a number of deaths, the Bureau the minimum level of 100 ppm. Though Minnesota. Type E toxin was isolated. of Commercial Fisheries under the such small concentrations of nitrite Since 1960, commercially-processed, U.S. Department of the Interior were not likely to have any significant smoked fish from the Great Lakes petitioned FDA for a regulation to preservative effect in the control of region has been responsible for four allow the use of NaNO 2 in chubs. A botulism, FDA instituted no action outbreaks of botulism which have regulation was published which re­ against any of the producers though involved 22 cases resulting in 10 quires chubs to contain not less than they were in direct violation of the deaths. In 1963, Michigan was the 100 ppm of sodium nitrite for effective regulations published by the FDA. location of an additional outbreak of preservation against botulism and per­ If a safe product is to be offered type E botulinum; but in this case, mits a maximum of 200 ppm. This to the consumer, it may be that the three persons were stricken after regulation also carries requirements use of nitrites is needed. The outbreaks eating commercially packed, canned for heat processing and an adequate of botulism due to smoked · fishery tuna from California. In 1963, this content of NaCI, both of which have a products are not common, but also they region was particularly hard hit. preservative effect. If such a level are not rare. A review of botulism out­ Smoked whitefish, vacuum-packed in correctly reflects the minimum nitrite breaks during the period 1899-1973 re­ Michigan and shipped to the adjoining content necessary for protection vealed the occurrence of 688 outbreaks states of Tennessee, Alabama, and against botulism, the effectiveness of involving a total of 1,784 cases with 978 Kentucky was the cause of 17 cases, in the low levels of nitrite found by the reported deaths. Four hundred and which 5 persons died. In this same USDA in meats as a prevention against ninety-five (72 percent) of these out­ year, two additional outbreaks bot ul ism becomes q uestiona ble. breaks have been traced to home occurred in Michigan and Minnesota, Actually, the level 100 ppm is in itself processed foods. Only 62 (9 percent) also due to commercially processed, open to question and closer exami­ outbreaks have been caused by com­ smoked whitefish. In 1967, commer­ nation may indicate a lower level of mercially processed foods. The source cially packed whitefish was the cause of nitrite may be sufficiently effective. of food responsible for the remaining an outbreak in Illinois. Whereas FDA's survey of the meat outbreaks is unknown. As a vehicle Type E toxin shows a widespread industry revealed a preponderance of responsible for botulism outbreaks, distribution along both the Atlantic samples of low NaNO 2 content, i.e., fish is relatively more important than and the Pacific coasts and in the Great much less than 200 ppm, this was not meat. During the period 1899-1973, Lakes Region. Alaska is the leading commonly the case with fish samples fishery products have been responsible state (12 outbreaks) reporting type E analyzed. In a 1969 preliminary survey for 4.4 percent of the total outbreaks, outbreaks which is due to the popu­ conducted by FDA to determine the beef 0.9 percent, pork 0.4 percent, and larity of certain foods such as cheese distribution of sodium nitrite in cold, poultry 0.4 percent. It is generally eggs or fermented salmon eggs with smoked fish, six plants were inspected. assumed that if botulism is caused by a certain groups of native Alaskans and Three of these firms were found to marine product, type E toxin is the widespread practice of home-pro­ have produced smoked salmon with responsible; but of the 29 outbreaks cessing. Up to the present, 32 out­ sodium nitrite contents in excess of 200 caused by fish products up to 1973, 19 breaks of botulism have occurred in the ppm. A 1970 survey also revealed some were due to type E, 7 were due to type United States which can be attributed smoked chub samples with excessively A, and 3 to type B. to fish and seafood. high nitrite concentrations. This is not The first reported outbreak of Although the need for nitrite in meant to imply that this situation is botulism in the U.S. due to fishery smoke-cured fish as a means of typical of most smoked fish producers. products occurred in 1932 and was preventing botulism has been stressed, Rather, it is intended to illustrate that caused by salmon caught and smoked the bacteriostatic action of nitrite is not violations of the regulations do exist, in Labrador. At that time, type E firmly established. It is not mandatory 27 that processors of cured, smoked fish Iyengar, and Sen, 1973), 197 samples of nitrosamines in meat products, it was use nitrites in their product to prevent various kinds of meat products were concluded that nitrosamine formation botulism. Sodium chloride in the con­ tested. Of these, 57 samples indicated was influenced mainly by heat treat­ centration range 2.5 percent-5.8 trace amounts (2-12 ppb) of DMNA. ment (sterilization, roasting, frying), percent has been reported to inhibit These included such products as ham but not by pH. No effects of bacterial outgrowth and toxin production by C. spread, luncheon meat, ox tongue, fermentation, increased salting, or botulinum type E (Abrahamsson, wieners, bologna, Polish and Ukranian increased addition of pepper or paprika Gullmar, and Molin, 1966; Segner, sausage, salami, pastrami, and bacon. was observed. No increase in nitrosa­ Schmidt, and Boltz, 1966; Christiansen Others were negative. No mass mine concentration attributable to et aI., 1968; Emodi and Lechowich, spectrometric confirmation of the dry salting was noted except in bacon 1969; Lechowich, 1970). However, identity of DMNA was carried out so which contained 45 ppmnitrosamines­ inhibition of outgrowth of types A and results should be considered as only mainly dimethyl-, diethyl-, piperidine, B spores requires a sodium chloride tentative. In only a few types of meat and pyrrolidine derivatives. No concentration of 8.2 percent-10.5 products did the concentrations of .relationship was observed between percent (Lechowich, 1970). It is nitrate and nitrite correlate with that residual nitrate or nitrite concentration generally agreed if the 180°F for 30 of DMNA detected in the samples. In a and nitrosamine content. Addition of minutes requirement is met and the later study by this same group (Pana­ ascorbic acid or its sodium salt resulted fish is subsequently distributed under laks et aI., 1974), of a total of 80 in increased concentrations of nitros­ adequate refrigeration with proper samples of different kinds of cured opyrrolidine. This is in contrast to sanitation, there would be no need for meat products. 17 contained 13-105 ppb other studies which have shown that the use of NaN02 • The complaint of nitrosopyrrolidine (NPy ); 29 samples the addition of ascorbic acid has acted industry is, however, that they are not contained 2-35 ppb DMNA; and 9 to decrease the amount of nitrosamines equipped to use that alternative and, samples contained 2-25 ppb diethyl­ formed in nitrite-treated meat products moreover, use of this alternative nitrosamine (DENA). In a few cases, (Mirvish et aI., 1972; Kawabata et aI., results in a product showing excessive identities were confirmed by gas-liquid 1973; Fan and Tannenbaum, 1973; thermal damage. Also, the possibility chromotography (GLC) and mass Fiddler et aI., 1973; and Mottram et that heat resistant mutants may evolve spectrometry. aI., 1975). must not be overlooked. In 1953, a Scientists with the USDA and FDA The quantity of cured meat con­ team of investigators (Dolman and have investigated the volatile nitrosa­ sumed in this country is high. Ap­ Chang, 1953) reported survivors mine content of bacon. High N­ proximately 70 percent of all pork among type E spores heated at 212°F nitrosopyrrolidine concentrations in produced annually in the United States (100°C) for 30 minutes. A second alter­ this product have been reported. The is cured. The per capita consump­ native would be to heat the 'product to FDA investigators (Fazio et aI., 1973) tion of pork in 1974 was 66.5 pounds an internal temperature of 150°F for 30 reported levels isolated from 8 com­ which means an average of 46.5 pounds minutes and have a minimum of 5 mercial brands ranging from 10-108 of cured pork was consumed by each percent salt in the water phase. It is ppb. This potent carcinogen was found person. This is more than 90 times the generally felt, however, that this in the cooked product but not in the raw amount of cured fish which is con­ produces a product that is too salty. form. Fat remaining in the pan after sumed. As a nation, we consumed (This is the problem which now con­ frying also contained nitrosopyrrolidine' about 2 billion pounds of wieners and fronts the meat and fish industries.) at levels ranging from 45-207 ppb. bologna in 1973, plus 66 million pounds The controversial status of nitrites Since approximately 1.5 billion pounds of smoked or dried beef, and 230 during recent years has resulted in of bacon are consumed each year, the million pounds of cured beef. extensive testing of a variety of meat presence of this nitrosamine in such a The quantity of cured fish consumed and fishery products by a number of popular product deserves much con­ per capita annually in this country is institutions, government and aca­ sideration. Studies (Pensabene et aI., small compared to that of meat. Of the demic, and private industry for nitrosa­ 1974) investigating the effect of levels total per capita consumption of 12.0 mine occurrence. Analyses of various of sodium nitrite and cooking on the pounds of all types of fish, only 0.5 cured meat products have disclosed the formation of NPy indicate that the con­ pound of cured fish is consumed. This presence of nitrosamines in many. A centration of this nitrosamine increases has not fluctuated greatly over the last concentration of dimethylnitrosamine with increasing nitrite levels. Samples 25 years, ranging between 0.4 and 0.7 (DMNA) has been detected in some which were pan fried showed the pounds. This does not lessen the ham samples at the 5 parts per billion highest concentration of NPy , while responsibility of the fish processor to (ppb) level (Fazio, White, and Howard, microwave-cooked samples showed the insure a safe product to the consumer; 1971). In other samples, it was non­ least. Concentrations of NPy appeared however, it would seem to indicate that existent. to be dependent upon the frying he could expect the same or equal Investigators of the Food Research temperature. judgment on his product as that which Division in Ottawa have made a study In a German study (Nagata and the processor of cured meat products of numerous cured meat products with Mirna, 1974) which was carried out to receives. regard to their nitrite and nitrosamine determine the effects of processing Although cured fish has come under contents. In one study (Panalaks, conditions on the concentration of investigation the same as has cured 28 meat, the nitrosamine concentrations vative. The agency had been expected Regulations of food additives-nitrites and nitrates. House Rep. 92·1338. found in any species have been rela­ to ban use of nitrite in the hot-smoked Dolman. C. E .. and H. Chan~ . 1953. The Epi· tively low compared to those isolated fish process, but FDA officials granted demiology and pathogeneSIs of type E and fish -borne botulism. Can. J. Public Health and measured in some meat products_ an extension after concern was ex­ 44 :231·244. Emodi. A. S .. and R. V. Lechowich. 1969 . Investigators at FDA have isolated and pressed that present temperature and Low temperature growth of type E Clo s­ confirmed by mass spectrometry levels other requirements may not be tridium botulinum spores. 1. Effects of sodium chloride. sodium nitrite. and pH. J. of DMNA ranging from 4 to 26 ppb effective to control C. botulinum types Food Sci . 34:78·81. from samples of raw, smoked, and A and B without the use of nitrites. Ender, F., and L. Ceh. 1968. Occurrence of nitrosamines in foodstuffs for human and smoked nitrite- and/or nitrate-treated The FDA believes that type E can be animal consumption. Food Cosmel. Toxicol. sable, salmon, and shad (Fazio, Damico, controlled without nitrites, but is not 6:569·571. Fan. T. Y.. and S. R. Tannenbaum. 1973. et aL, 1971). Though no nitrosamine as certain about the more heat-resis­ Natural inhibiwrs of nitrosation reactions: The concept of available nitrite. J. Food . Sci . was detected in the raw salmon and - tant types A and B. Studies on the 38 :1067-1069. shad, in the raw sable a level of 4 ppb effect of nitrite on outgrowth and toxin Fazio. T .. J. N. Damico. J. W. Howard. R. H. White. and J .O. Watts. 1971. Gas chromato­ was measured. In a separate study production by C. botulinum in hot- and graphic determination and mass spectro· (Howard, Fazio, and Watts, 1970) cold-smoked fishery products are being metric confirmation of N-nitrosodimethyla· mine in smoke· processed marine fish. J. conducted by this same group on conducted by the National Marine Agric. Food Chern. 19 :250·253. smoked, nitrite-treated chub, such Fisheries Service. Fazio. T .. R. H. White. L. R. Dusold. and J . W. Howard . 1973. Nitrosopyrrolidine in cooked very low levels of 1-2 ppb detected (de­ The formation of N-nitroso com­ bacon. J. Assoc . Off. Anal. Chern. 56 :919-921. Fazio, T .. R. H. White. and J . W. Howard. monstrated sensitivity of method 10 pounds in food products and in bio­ 1971. Analyses of nitrite· and / or nitrate· ppb) led to the conclusion that DMNA logical systems is not completely processed meats for N.nitrosodime~hyla . mme. J. Assoc. Off. Anal. Chern. 54 .1157· was not formed under processing understood. A problem of nitrosamine 1159. conditions in the nitrite-treated fish. research is the minute occurrence of Fiddler. W .. J . W. Pensabene. E. G. Poitrow· ski. R. C. Doerr. and A. E . Wasserman. Even fortification of the fish with large these substances in food. Not only are 1973. Use of sodium ascorbate or erythor· amounts of trimethylamine hydrochlo­ bate to inhibit formation of N·nitrosodi· these compounds elusive in behavior, methylamine in frankfurters. J. Food Sci. ride (1,500 ppm) and treatment with but their detection is most tedious. 38:1084. Gadbois. D. F .. E. M. Ravesi. R. C. Lundstrom. nitrite at high levels (2,500 ppm) prior Occurrences at the parts per billion and R. C. Maney. 1975. N·nitrosodimethyla­ to smoking did not cause an increase in level make their extraction and mine in cold -smoked sablefish. J. Agric. Food Chern. 23:665·668. the apparent amount of DMNA . Nitros­ isolation necessarily exacting, and Gruger. E. H .. Jr. 1972. Chromato~aphic an.· amine studies conducted at the North­ techniques currently being used could alyses of volatile amines in maTlne fish . J . Agric. Food Chern. 20:781·785. east Utilization Research Center of the benefit from improvements. No doubt, Hedler. L .. and P. Marquardt. 1968. Occur· National Marine Fisheries Service rence of diethylnitrosamine in some samples many erroneous results have been of food. Food Cosmet. Toxicol. 6:341-348. have also revealed the presence of only reported, and initial findings should be Hoffmann. D .. S. S. Hecht. R. M. Ornaf. and E. L. Wynder. 1974. N·Nitrosonornicotine in trace amounts « 10 ppb) of DMNA in confirmed. The problem of nitrites and wbacco. Science (Wash .. D.C.) 186:265·267. cold-smoked sablefish to which had nitrosamines today calls for vast Howard. J. W .• T. Fazio. and J . O. Watts. 1970 . Extraction and gas chromotographic been added nitrite at levels ranging amounts of additional research in all determination of N ·nitrosodimethylamine in from 0 to 550 ppm (Gadbois et aI., areas-detection, formation, and the smoked fish: Application to smoked nitrite· treated chub. J. Assoc. Off. Anal. Chern. 1975). Concentrations of DMNA in establishment of tolerance limits. 53:269·274 . these samples showed no apparent Kawabata. T .. M. Kurihara, E. Kasai. and C Nitrite additives-harmful or neces­ Yoshida. 1973. Formation of dimethylnitros· increase when samples were stored for sary? They may be both, but a amine in salted Alaska pollock roe products and a preventive method (In Jap., Eng!. two weeks at refrigerated tempera­ cooperative effort must be made by abstr.) Bull. Jap. Soc. Sci. Fish. 39:883·889. tures (40°F). Twenty-four samples of private industry and federal officials Lane. R. P .. R. H. Rice. and M. E. Bailey. 1974. Gas chromawgrallhic-mass spectro· various salmon roe products packed by before a more comprehensive answer metric determination of N-nitrosodimethyla· Japanese producers were also investi­ can be given. mine formed in synthetic and human gastric juice. J . Agric. Food Chern. 22:1019-1023. gated by this group. The presence of LITERATURE CITED Lechowich. R. V. 1970. The effects of chemicals DMNA in all samples analyzed was too upon the growth of Clostridium botulinum. Abrahamsson, K .. B. Gullmar. and N. Molin . In M. Herzberg (editor). Proceedings of the low for confirmation_ Twenty-three 1966. The effect of temperature on toxin for­ first U .S.·J apan conference on WXIC micro­ mation and toxin stability of Clostridium organism~ p. 468-475. U.S. Gov . Print. Off.. commercially prepared salted Alaska botulinum type E in different environments. Wash. D.I", . pollock roe samples analyzed for nitros­ Can. J. Microbiol. 12: 385·394. Magee. P. N. 1971. Toxicity of nitrosamines: Cantoni. C .. P. Renon. and V. L·AcQua. 1974. Their possible human health hazards. Food amines by a Japanese team of scientists Nitrates. nitrites and nitrosamines in meats Cosmet. Toxicol. 9:207·218. showed almost no DMNA (Kawabata and viscera of calves fed with milk substi· McGlashan, N. D .• C. L. Walters. and A. E. M. tutes containing nitrates. Arch. Vet. Ital. McLean . 1968. Nitrosamines in African alco· et aI., 1973) . In most cases, it was 25(1 / 2):21-27 . holic spirits and oesophageal cancer. Lancet below or around the detection limit of 1 Cassens. R. G .. J. G. Sebranek. G. Kubberod. 2:1017. and G. Woolford. 1974. Where does the Mirvish, S. S .• L. Wallcave. M. Eagen, and P. ppb, except in one sample from which nitrite go? Food Prod. Develop. 8(10):50-56. Shubik. 1972 . Ascorbate-nitrite reaction: Center for Disease Control. 1974. Botulism in Possible means of blocking the formation of 6.7 ppb DMNA was detected. the United States. 1899·1973. Handbook for carcinogenic N-nitroso compounds. Science The FDA has placed the use of epidemiologists. clinicians. and laborawry (Wash., D.C.) 177:65-68. workers. Public Health Serv .• U.S. Gov . Mottram. D. S .• R. L. S. Patterson, D. N. nitrite in both hot-smoked fish and Publ., Readex Microprint 09584. N. Y. Rhodes. and T. A. Gough. 1975. Influence of cold-smoked fish processes under Christiansen, L. N., J. Deffner, E. M. ascorbic acid and pH on the formation of N· Foster. and H. Sugiyama. 1968. Survival and nitrosodimethylamine in cured pork con­ interim food additive regulation until outgrowth of Clostridium botulinum type E taining added dimethylamine. J. Sci . Food tests are completed to establish the spores in smoked fish. Appl. Microbiol. 16: Agric. 26 :47-53. 133·137. Myslivy. T . S .. E . L. Wick, M. C. Archer. R. C. safety and the need for the preser- Committee on Government Operations. 1972. Shank. and P . M. Newberne. 1974. For·

29 mation of N-nitrosopyrrolidine in a dog's 1967 . Observations on the inhibition of vege­ Food Cosmet. Toxicol. 10 :219-223. stomach _ Br. J. Cancer 30 :279-283. ta ti ve cells of Clos tridium sporrmgenes by Sen, N.P., L. A. Schwinghamer, B. A. Nagata, Y., and A. Mirna. 1974. Effect of pro­ nitrite which has been autocla ved in a labora­ Donaldson, and W. F. Miles. 1972. N-ni­ cessing on nitrosamine formation in meat tory medium, discussed in the context of sub­ trosodimethylamine in fish meal. J _ Agric. products. Fleischwirtschaft 54(11) :1781 - lethally processed cured meat. J _ Food Food Chem. 20 :1280-1281. 1786_ Technol. 2:377-397. Sen, N. P., D. C. Smith, andL.Schwinghamer. Panalaks, T_, J. R. Iyengar, B. A. Donaldson, Preussmann, R. 1974 . Formation of carcino­ 1969. Formation of N-nitrosamines from W. F . Miles, and N. P. Sen. 1974 . Further gens from precursors occurring in the secondary amines and nitrite in human and survey of cured meat products for volatile N ­ environment: New aspects of nItrosamine a~imal gastric juice. Food Cos met. Toxicol. nitrosamines. J . Assoc. Off. Ana!. Chem. 57: induced tumor genesis. Cancer Res. 34 :9 -15. 7 .301 -3(J7. 806-812. Sander, J ., and F. Seif. 1969. Bakterielle re­ Sen, N. P., D_ C. Smith, L. Schwinghamer, and Panalaks, T., J. R. Iyengar. and N. P. Sen. duktion von nitrat im magen des menschen B. Howsam. 1970. Formation of nItrosa mines 1973 . Nitrate, nitrite, and dimethylnitrosa­ als ursache einer nitrosamm-bildung. Arnei­ in nitrite treated fish . Can . lnst. Food Tech­ mine in cured meat products_ J . Assoc. Off. mittel-Forschung 19:1091 -1093. no!. J. 3:66-69. Anal. Chem. 56:621-625. Segner, W. P., C. F. Schmidt, and J. K. Boltz. Sen, N. P., D. C. Smith, L. Schwinghamer, and Pensabene, J . W., W. Fiddler, R. A_ Gates, J. 1966. Effect of sodium chloride and pH on the J . J. Marleau_ 1969. Diethylnitrosamine and C. Fagan, and A. E. Wasserman. 1974 . outgrowth of spores of type E_ Clostridium other N -nitrosamines in foods. J . Assoc. Effect of frying and other cookin~ conditions botulinum at optimal and suboptimal Off. Anal. Chem. 52:47 -52_ on nitrosopyrrolidine formation m bacon. J . temperatures. Appl. Microbio!. 14 :49-54 . Swann, P. F., and P . N. Magee. 1971. Nitros­ Food Sci. 39:314-316. Sen, N. P . 1972. The evidence for the presence amine-induced carcinogenesis_ Biochem. J . Perigo, J . A ., E. Whiting, and T. E. Bashford. of dimethylnitrosamine in meat products. 125:841 -847 _

MFR Paper 1185. From Marine Fisher ies Review, Vol. 38, No.4, April 1976 . Copies of this paper, in limited numbers, are avaifable from D825, Technical Information DiviSion, tnvironmental Science Information Ce nter, NOAA , Washington, DC 20235. Copies of Marine Fisheries Review are available from the Superintendent of Doc uments, U. S. Government Printing Olfice, Washington, DC 20402 for $1 . 10 each.

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