Thousands of years ago, the Rabbis of old recognized that Jewish identity is the key to the survival of Klal Yisrael. To this end, they enacted three sets of food laws to limit socialization: bishul akum, pas akum, and stam yainom (cooked food, bread, and wine prepared by gentiles). This was based on the realization that bonds of friendship are established by eating together, and breaking bread with a stranger is the first step to developing a closer relationship. For thousands of years of exile, the biblical and rabbinic laws of kosher have formed a natural fortress that prevented the assimilation of the Jewish people into many different cultures of the world. Today, with spiraling assimilation wreaking havoc at a frightening rate, the prophetic vision of Chazal is all the more apparent. It is significant that even for secularized Jews, a kosher kitchen often remains the last bastion against intermarriage and assimilation.
More than two thousand years ago, the Rabbis1 prohibited eating certain foods cooked2 by non-Jews in order to limit socialization which might lead to intermarriage between Jews and gentiles3. This prohibition is known as bishul akum. Food which has a bishul akum status is no more kosher than a sandwich of cold roast beef and cheese4, even though the ingredients used to prepare the food were initially kosher in and of themselves.
In recent years, with many women entering the workforce, it has become increasingly more prevalent for non-Jewish5 help to prepare meals while a couple is away from home. Unfortunately, many people are completely unaware that food prepared by a non-Jewish live-in maid or babysitter may not be kosher, and even their utensils, pots and pans may require kosherization6. Though certain foods are excluded from this prohibition the typical family dinner consists of meat, poultry, fish, and other items which are definitely restricted when cooked by a gentile. As indicated in the quiz, this problem has been exacerbated by the introduction of stoves with electronic ignition rather than standing pilot lights. Why electronic ignition is a factor in bishul akum reflects an important aspect of this area of halachah.
There is a dispute among the Rishonim (early commentators) whether bishul akum is negated when a Jew contributes to the cooking process by lighting the fire before a non-Jew places a pot of food on the stove, The major codifiers of Jewish law argue this point as well.
Rav Yosef Caro, author of the Shulchan Oruch, subscribes to the stringent opinion, and this is the custom practiced by Sephardic Jewry. According to this view, a Jew must place the pot on a burning fire in order that the food be considered bishul yisrael7. Alternatively, a Jew may turn on the fire after a non-Jew placed the pot on the cold stove8, The Ramo follows the lenient opinion, and allows a gentile to place raw food on a fire that was ignited by a Jew. Since the Jew has a share in the overall process, the food is, not considered to be bishul akum. The Ramo goes one step further, and writes that if a Jew has even a partial role in preparing the fire, bishul akum does not apply. For example, if a Jew added a wood chip or any other fuel to the fire9, or alternatively, if a non-Jew lit a fire from another fire which was originally ignited by a Jew, there is no restriction of bishul akum. In both of these instances, the fire is considered aish yisrael (fire of a Jew) because of the involvement of the Jew. Jews of Ashkenazic descent follow this ruling, and accordingly, a non-Jew may turn on a gas burner which is ignited from a pilot light that was lit by a Jew10. However, stoves with pilot lights are no longer common, and it is important that observant Jews realize the serious halachic concerns associated with meals prepared by hired help11.
The reader is perhaps wondering who turns on the fires in factories around the world in remote locations that are supervised by the OU and other kosher organizations. Although many foods are prepared without any heat (for example, mayonnaise and pickles), there are numerous other products that are cooked. In truth, members of the Rabbinic staff of the OU spend a disproportionate amount of time seeking halachic and practical solutions to the problems of bishul akum, and where no solution is found, supervision is not granted.
In some instances, it is possible to effect bishul yisrael (for example, in restaurants and meat processing plants where there is a mashgiach timid12 ), but generally there is a halachic basis to supervise a product without bishul yisrael. There are many instances where bishul akum does not apply for a variety of reasons, which we will now examine.
EDIBLE IN A RAW STATE
Food that can be eaten in a raw state is not prohibited when cooked by a non-Jew13. Since the food is edible without preparation, the consumer feels minimal appreciation to the chef, and eating the food does not engender socialization. Some foods that fall into this category are: water, oil, butter, jam and jelly, juice, honey, yogurt, canned fruit, flavored drinks, milk, ice cream, banana chips, nuts, cheese, vinegar, ketchup, sauces, apple sauce and many canned vegetables (com, string beans, peas, carrots, mushrooms, cucumbers, peppers, etc.
NOT SERVED AT A ROYAL TABLE
Food that is not fit to be served at a royal dinner14 may be prepared by a non-Jew. Here, too, the level of appreciation to the cook is minimal since the food is not a prestigious item. Some examples of this group are as follows: cereal, potato chips15 com chips, donuts16, canned beans, popcorn17, and candy.
It is often difficult to establish whether a particular food is fit for a royal dinner. For example, the Chochmas Adam (66-4) writes that bishul akum applies to potatoes, while the Oruch HaShulchan (113-18) maintains that potatoes are a poor man’s staple. In addition, these issues must be revisited in every generation, and one cannot point to halachic precedent, since the determination of what is served at a royal dinner is subject to contemporary custom. Today, it is not uncommon to find mashed potatoes and potato fries at elaborate meals, and even the Oruch HaShulchan would perhaps agree that potatoes are now fit for a royal table18.
REQUIRES FURTHER PROCESSING
What if the gentile cooks food to the point where it is partially edible, but a Jew completes the cooking process? According to Rav Yosef Caro, this situation normally constitutes bishul akum, while the Ramo maintains that the partial involvement of the Jew is sufficient to be considered bishul yisrael19. Many kosher agencies who follow the Ashkenazic tradition of the Ramo allow non-Jewish companies to prepare specific types of food that cannot be used out of the container without further processing. Since these items will require additional cooking in any event, it is assumed that the final stages will be done by a Jew and the product will then be considered bishul yisrael. Examples of this category include: parboiled rice, water chestnuts20, canned potatoes21, frozen French fries, latkes & tater fries22 and instant potatoes23 and pasta.
Bread items were not included in the restriction of bishul akum24 and are governed by a completely different set of rules. Many are of the opinion that the sages initially prohibited bread baked by a gentile (pas akum) but later rescinded this restriction for commercial bread (pas palter) which is a staple food item.
Some authorities allow the purchase of pas palter if pas yisrael of comparable quality is unavailable25, while others permit pas palter under all circumstances26. Since the restriction was rescinded only because of necessity, many people who are medakdek b’mitzvos (scrupulous in mitzvah observance) refrain from eating pas palter under all conditions27. Nonetheless, many kosher agencies follow the basic halachah, and endorse products which are pas palter28.
Pas palter includes a category of products known as pas haboh bikisinin29. Some common examples of pas haboh bikisnin are pie, cake, cookies, pretzels, bread sticks, flat bread, crackers and kichel. (See Kosher column in Jewish Action, Vol. 54, No.2 for elaboration on this topic.)
MAIN COMPONENT IS WATER
Tosofoth30 states that bishul akum is not a concern with respect to beer, even though the grain component is cooked, since the majority is water. Pri Chodosh31 extrapolates that for this reason, coffee (or tea) and cocoa are permissible32.
One of the most fascinating applications of the halachos of bishul akum is with respect to the processing of fish. This is a broad topic, and to discuss it properly we must distinguish between three categories of processed fish: cold smoked fish, hot smoked fish and canned fish.
Cold smoked fish is least problematic. Salmon (which includes lox) is generally not processed with heat. Rather, the fish is hung in a smoke house, and the chamber is filled with a cold smoke which cures the fish and changes its texture. Since there is no heat, this process can be performed by a non-Jew without consequence of bishul akum33. Other types of smoked fish such as whitefish, sable and tuna, are usually processed with smoke and heat. Because this is a hot process and the fish are suitable for a royal banquet, the issue of bishul akum is a serious matter of concern34. The OU and other Kosher agencies have dealt with this in several different ways. The range of solutions to this problem are as follows:
a) A mashgiach is present to turn on the oven or light the fire.
This however, is not always economically feasible.
b) The pilot light is lit by a Jew. Unfortunately, some smoke house ovens are not and cannot be equipped with pilot lights.
c) The fish is smoked cold and rendered completely edible before it is smoked with heat35. Just as there is no restriction of bishul akum for food which is edible in a raw state (as explained above), similarly there is no concern of bishul akum for fish that was processed with cold smoke (and thus rendered edible in a permissible manner) before the hot process began. Some companies do this as a matter of course. Other companies have introduced cold smoke before the hot smoke to obviate the problem of bishul akum. In the latter case, the method of processing needs to be carefully monitored to ensure that the cold smoking actually occurs.
Rabbi Yehuda Shain has recently developed an ingenious system whereby the mashgiach can monitor the production from an off-site location. By installing a special device, it is possible to turn the oven on and off through the use of a touch-tone phone.
d) It has been suggested by some rabbis that an electric light bulb can be installed in an oven as a solution to the problem of bishul akum. Since the bulb produces some minimal heat, the bulb can be compared to a wood chip thrown into the fire by a Jew, which we discussed earlier in this article. The bulb can be installed to burn continuously, and it is therefore not necessary for the mashgiach to be present on a constant basis.
Various poskim have argued against the light bulb system. When a Jew adds a wood chip to a fire, it is rendered aish yisrael because the Jew is instrumental in preparing and intensifying the fire. In contrast, a light bulb remains separate and distinct from the fire, and the Jew is not a contributor to the primary source of heat. Others have raised another interesting objection. Electric companies typically change the source of power from one generator to another. Even if a Jew installs a light bulb, it would no longer be considered a fire of a Jew if the generator was subsequently changed by the electric company. In halachic terminology, this is referred to as kolu lo chitzov (his arrows – i.e.
his action – has ended). The OU does not subscribe to the light bulb system, though a number of other kosher organizations do utilize the light bulb heter.
e) Rav Moshe Feinstein, zt“l. ruled36 that there is no prohibition of bishul akum in a factory that uses specialized equipment, for the following reason: In truth, if the non-Jewish cook is unknown to the consumer, bishul akum should not apply, since eating the food item would not lead to socialization. Nonetheless, bishul akum is in effect even in such cases of anonymity because the Rabbis established uniform decrees (lo plug) without allowing for the variations of every individual situation. However, if the food is processed in equipment which is completely different than normal household cooking utensils37, bishul akum does not apply. Since the processing equipment is totally unique, the concept of uniformity (lo plug) is not operative.
Because this position has not received universal acceptance, the OU generally does not rely on this leniency alone without other supporting considerations (though at least one major kosher organization does follow this ruling completely).
Canned fish is cooked in a steam chamber called a retort, and it does not lend itself to
most of the solutions described above. Most fish companies are located in distant places like Puerto Rico, Alaska, Spain and Thailand, and it is extremely expensive to station a full time mashgiach at the plant to turn on the fire. At times, the OU does oversee special productions of canned tuna fish with full-time supervision, in which case the mashgiach turns on the steam. Such cans are identified by a code of letters on the label: MT (mashgiach temidi – full-time supervision) BY (bishul yisrael). However, this type of supervision is the exception.
Essentially, the halachic position of the OU is that canned fish does not become forbidden as a result of bishu1 akum, since the fish is not suitable for a state dinner. This argument is strongest for sardines, which are not gourmet fish. Indeed, the Levushai Mordechai38 testified that many European Torah scholars and great tzaddikim ate sardines which were prepared by gentiles, though this was not a universal practice39. Tuna and salmon are higher quality fish, and tuna steaks and baked salmon are served at elegant dinners. Nonetheless, the manner in which canned fish is prepared renders them inappropriate for a meal of the aristocracy: A gourmet chef would not attempt to prepare an exquisite fish platter with canned tuna, salmon or sardines. Coupled with this is the ruling of Rav Moshe Feinstein, z“t1, mentioned earlier, that bishu1 akum does not apply to a factory.
In the case of tuna, there is an additional mitigating factor. Unlike salmon and sardines which are first cooked in the sealed can, tuna is steamed in a steam chamber before it is packed and re-cooked in the can. It is questionable whether food that was steamed by a non-Jew is prohibited because of bishul akum. The Shulchan Oruch40 makes it clear that smoking does not constitute bishul akum, and it is debatable whether steam has the same status41. RavYitzchok Weiss, zt”l42 rules that there is no bishul akum for products steamed in a factory, since there are two uncertainties that coincide: a) it may be that there is no bishul akum for steam processing, and b) it may be that there is no bishul akum in a factory where the workers are unknown to the consumer43. Although we would not rely on either consideration alone, Rav Weiss allows a lenient ruling when both factors are present44.
It has been argued that the same leniency can be applied to canned salmon and sardines as well. Though they are not precooked like tuna, the product is cooked with steam in the sealed can. Others maintain that the uncertainty of whether bishul akum applies to steam exists only when the product is heated directly by the steam, as is the case with tuna. On the other hand, if the steam heats the can and the product is cooked in the liquid of the can, the steam serves only as a vehicle for the transfer of heat, but the actual cooking occurs in the boiling broth45.
Food is a double-edged sword. While nutritious food provides basic sustenance and energy, spoiled food can have a devastating and even fala1 effect on the human body. This same dichotomy is equally true for the spiritual dimension of man. Food consumed in conformity with the laws of the Torah elevates and sanctifies, while non-kosher food destroys and defiles the Jewish soul. On both levels, it’s not only what’s in the food that matters, but how it’s prepared as well. Indeed, we are playing with fire.
Here is a short quiz of ten questions to test your knowledge of some of the finer points of kosher: All the questions have one answer alluded to by the title of this article.
1. What kosher problem may be obviated by using a touch-tone phone?
2. Contemporary rabbis dispute the use of a light bulb to solve which kosher concern? 3. Of what particular interest is it to the Jewish community what the Queen or King of England serves at royal dinners?
4. Why is MTBY printed on some cans of OU tuna fish?
5. What situation became exacerbated by the introduction of stoves with electronic ignitions?
6. How can kosher food be rendered non-kosher without adding a single ingredient?
7. What law of kosher was instituted to prevent intermarriage?
8. What halachah of kosher is often of greater concern when husband and wife both work?
9. Sephardim and Ashkenazim disagree whether a wood chip can be used to resolve what issue?
10. What relevant law of kosher is unknown to many people?
If you knew that the answer to these questions was bishul akum, congratulations! You have just won First Prize in the OU Kosher Bee, and you are eligible to win the Grand Prize (an extended stay in olam haba, after 120 years). If you did not know the answer, you may wish to read on, to help secure your share of the Grand Prize as well.
1 Mishna Avoda Zorah 2:6. Tosofoth, Avoda Zorah. 37b. writes that the laws of bishul akum were enacted at an early period even before Hillel and Shammai.
2 In the laws of bishul akum, bishul (cooking) is used generically and includes baking (Yoreh Daya 173:3), frying (Chochmas Adam 66:6) and broiling (Gilvon Maharsha 113:1) as well.
3 Intermarriage is the reason cited by Taz , Yoreh Daya 113:7, based on Tosofoth. Avodah Zora, 38a. Rashi in Avodah Zora (ibid), maintains that the Rabbis restricted socialization to prevent the inadvertent consumption of non-kosher food. The Pischai Teshuva, Yoreh Daya 113:7, notes that according to Rashi, the prohibition would include food prepared by non-observant Jews as well. See the responsa of Minchas Yitzchok, Vol. 3, 73, who takes a stringent view of this matter. Kaf HaChayim, Yoreh Daya 113:1 rules that b’dieved (after the fact) one can be lenient since we are dealing with a sofek dirabonon (uncertainty about a rabbinic question). Yabia Omer. Vol. 5, 10, also agrees that it is preferable to have a religious Jew prepare food, while Tzitz Eliezer, Vol. 9, 41, rules in favor of the lenient view.
4 I chose this example because milk and meat, when eaten (but not cooked) together, are prohibited on a Rabbinic (and not Biblical) level, as is bishul akum.
5 According to the majority of opinions quoted in footnote 3, it is also preferable not to allow a non-religious Jewish housekeeper to prepare food.
6 Yoreh Daya 113:16.
7 Yoreh Daya 113:7.
8 Yabia Omer, Vol. 5, responsa 20:7.
9 For a modem oven, this is the equivalent of raising the temperature setting. Rabbi Yisrael Belsky, shlita, maintains that this is effective only if raising the temperature setting immediately turns on or increases the size of the fire. Simply changing the thermostat setting to cause the fire to burn longer does not constitute bishul yisrael.
10 Rabbi Yisroel Belsky related that Rav Moshe Feinstein, zt“1 was not happy with the common practice of relying on a pilot light to resolve the problem of bishul akum, presumably because the pilot light burns indefinitely and it is difficult to consider this as a perpetual aish yisrael. Furthermore, not all poskim are in agreement with the Rama regarding a gentile lighting a fire from aish yisrael. See for example, Gra,113:18. Nonetheless, Rav Moshe, zt“l stopped short of prohibiting this common practice. In addition, it should be emphasized that one can rely on a pilot light only if it is unlikely that it will be extinguished. In restaurants, pots overflow regularly and the pilot light is often not lit. One of the primary responsibilities of a mashgiach in a restaurant is to over see the fires and make certain they are not turned on by the help. Similarly, if the pilot light of a home stove is prone to go out regularly, there is no guarantee that the non-Jew will not relight it when the residents are away from home.
11 A separate issue that must be dealt with when non-Jewish help is left alone in a house is the concern that they may use the kitchen utensils to prepare non-kosher food. See Yoreh Daya 118:12 and Igros Moshe Vol. 1,61.
12 It is worth noting that it is a common practice in better restaurants for a chef to cook dishes at the customer’s table. The mashgiach must light the sterno used at the table in addition to turning on the stove and oven located in the kitchen. Similarly, sternos are sometimes used to cook some items at smorgasbords, and this requires the same attention.
13 Some are of the opinion that a person of stature should preferably refrain from eating bishul akum even when the food is edible in a raw state. See Shach, Yoreh Daya, 152:2, and responsa of Shevet HaLevi, Vol. 6, 108:3. However, Oruch HaShu1chan 113:11 quotes many poskim who reject this view.
14 We refer to a royal dinner bemuse the Talmud speaks of shulchan melachim, a king’s table. However, the Kaf HaChayim 123:2 explains that the intent is not limited to a king, but includes any person of stature.
15 There are some who have argued that a food item that can be prepared as a sumptuous dish by a skilled chef is prohibited even when cooked in a manner that would be unsuitable for a royal dinner. It would then follow that potato chips are not kosher if cooked by a non-Jew, since potatoes am be prepared in other manners that are in fact appropriate for a state dinner. See, for example, the Tifereth Yisrael, Avoda Zorah, 2:52; Pischai Halacha, page 116, responsa 17 from Rav Moshe Stern, shlita; Teshuvos V’hanhogos from Rap Moshe Sternbach, shlita, responsa 438. Nonetheless, many contemporary poskim lire not in agreement with this view, and a variety of proofs have been brought to disprove the former position. As an example, the Ramo, Yoreh Daya 113:2; writes that toasted afunim (a type of bean) are not fit for a royal feast, while the Rambam, Ma’acholos Asuros 17:18, rules that baked afunim are prohibited. For an extensive discussion in support of the latter position, see the article of Rabbi P. Falk, shlita, Am HaTorah, Mahadurah 3, vol. 10, page 75.
16 Source: Rabbi Yisrael Belsky. Yechava Daas suggests another reason to permit donuts cooked by a non-Jew. Donuts are boiled in oil. There are two opinions cited in Orach Chaim 168:13, whether boiled dough products are considered “bread”. With respect to the appropriate brachah, we follow the lenient opinion and recite borei minai mezonos, since brachos are a Rabbinic institution. However, with respect to bishul akum, which is also a Rabbinic decree, we assume they are “bread.” As noted later in this article, there are no bishul akum restrictions on bread items.
17 Even though corn is included in the category of foods that can be eaten raw, I have also placed popcorn in the group of foods that cannot be served at a royal table. This is because there is an opinion that a food that initially can be eaten raw that is dried to the point where it can no longer be consumed in a raw state is governed by the laws of bishul akum. See Darkai Teshuva, 113:4. According to this position, dried corn used for popcorn is not treated as a food that can be eaten raw. Nonetheless, popcorn is permissible since it is not served at state affairs.
18 Contemporary poskim often disagree whether specific items are fit for a royal feast. For example, Rav Moshe Heineman, shlita, (in Kashruth. Kurrents, Fall 5754-1993) singles out canned asparagus as the only prestigious canned vegetable that cannot be eaten raw where bishul akum is applicable. Rav Yisrael Belsky shared with the author that he believes that canned asparagus would not be used at a state dinner because of its soft texture (but in any event it should not be eaten because of concerns of insect infestation). On the other hand, Rabbi Belsky maintains that canned yams are suitable for a state dinner, and bishul akum applies.
19 Yoreh Daya, 113:9.
20 Caterers and chefs generally stir-fry water chestnuts with other vegetables. Rav Belsky, pointed out two additional reasons to exclude water chestnuts from bishul akum. First, the Shach, Yoreh Daya, 173:1, favors the opinion of those poskim that if cooking does not change the item, bishul akum does not apply. Second, the water chestnuts are not eaten alone without the combination of other vegetables. Therefore, water chestnuts in and of themselves cannot be viewed as fit for a royal table.
21 Typically, caterers bake canned potatoes.
22 This is only the case if these items are not fully cooked, and each brand should be tested separately.
23 Instant potatoes are fully cooked before they are dehydrated and made into flakes or powder. Nonetheless, Rav Belsky related from Rav Elyashuv, shlita, that they are permitted, based on the Avkas Rochel, quoted in the Yad Efraim, Yoreh Daya, 113:12, that food cooked by a non-Jew which was rendered inedible by dehydration and then was re-cooked by a Jew is not prohibited because of bishul akum. This same reasoning of the Avkas Rochel applies to instant potatoes which are prepared with hot water. Rabbi Belsky pointed out that this is the case only if instant potatoes cannot be made with cold water, and this assumption should be regularly re-examined.
24 There is an opinion that if a gentile bakes dough that belongs to a Jew it is considered bishul akum. See Tur 112 and Igros Moshe, Yoreh Daya, Vol. 1, responsa 45.
25 Yoreh Daya 112:5 and Shach 112:9.
26 Ramo, 111:2.
27 Oruch HaShulchan, 112:17.
28 Even those who eat pas palter should refrain from doing so during the Ten Days of Repentance (Orach Chayim, 603). Some poskim also recommend not eating pas palter on Shabbos and Yom Tov. See Mishnah Brura 242:6.
29 Pas palter is defined as any product baked by a gentile on which one recites hamotzi, either normally, or when there is kvias seudah (a full meal is eaten). See Taz, Yoreh Daya, 112:6, and Pri Chodosh, Yoreh Daya 112. One recites hamotzi on pas haba bikisnin whenever there is kvias seudah. For a full discussion of pas haba bikisnin, see the article by this author in Jewish Action, winter, 1993.
30 Avodah Zorah 31b, V’tarvayhu.
31 Yoreh Daya 112:17 and 114:17.
32 Nonetheless, there are those who disagree with the Pri Chodosh and prohibit coffee, tea or chocolate that were brewed by a gentile. See, for example, Pishchai Teshuva, 114:1, who cites Ponim Meiros that the reasoning of Tosafoth (that beer is permissible because the majority is water) is not the accepted halachah. See also the responsa of Shevet HaLevi, Vol. 2,44.
33 Smoking a food does not constitute bishul akum (Yoreh Daya, 113:13).
34 Some argue that there is no bishul akum even with a hot smoke process. See my discussion of this matter in Mesorah, Vol. 6, and the article of Rabbi P. Falk, Am HaTorah, Mahadurah 3, Vol. 10.
35 The basis for this allowance is Yoreh Daya, 113:12 and Shach 113:18.
36 Verbal discussions with Rav Nathan Greenblatt, shlita, and Rabbi Yisrael Belsky, shlita. See article of Rabbi Menachem Genack, shlita, Mesorah,Vol.1.
37 Rav Moshe, zt”l emphasized that if the cooking equipment in the factory is simply larger than the standard kitchen pots and pans, this does not constitute a unique situation. Rather, they must lie totally different in structure and design, which is often the case in a factory.
39 Shevet HaLevi Vol. 6. 106 relates that the Chazon Ish did not eat sardines that were prepared by a gentile.
40 Yoreh Daya, 113:13.
41 The issue of bishul akum for a steam process is disputed by the Zer Zahav and Shem Aryeh, quoted in Darkei Teshuva 113:16. Some rabbinic authorities rule leniently in this matter even without other mitigating factors. See, for example, responsa of Yabia Orner, Vol. 5, 9, and responsa of Seridai Aish, Vol. 2, 138. Rabbi Weiss, however, relies on the lenient position only in a factory situation, where there is an issue of anonymity as well.
42 Responsa of Minchas Yitzchok, vol. 3; 26:6.
43 This is the position of the Maharit Tzolin quoted by the Birkai Yosef in Yoreh Daya 113, though almost all halachic authorities reject this opinion.
44 For a full treatment of the issue of bishul akum in canned tuna, see the article by Rabbi Menachem Genack, Rabbinic Administrator, OU Kashruth Division, in Mesorah, Vol.1.
45 See Minchas Yitzchok, Vol.1O,67, and articles of Rabbi Hershel Schachter, shlita, Mesorah, Vol.1, and Rabbi Genack, Mesorah, Vol. 8.