Rav Baruch Rubanwitz a Dayan in the Beis Hahora’ah
Fruits, vegetables, fish and treif knives
- Fresh fruits and vegetables grown in chutz la’aretz are kosher whether bought whole or cut. Therefore, you may purchase a fresh fruit salad in any restaurant (if there is no dressing on it). If the restaurant serves kosher and non-kosher items, you may enter it to eat. If none of the food served is kosher, you may only be seated if there are no Jews around to see or if you are not recognizable as Jewish. Although you couldn’t eat there, you might want to enter for a meeting with someone and just drink water.
- You may drink cold drinks such as soda and beer in the glasses provided in a non-kosher restaurant. If the drink is normally served with a slice of lemon, ask them to hold the lemon. Since the lemon was cut with a treif knife, the lemon is treif and should not be put into tea or a cold beverage. If it was wedged on the glass, you should remove the lemon and may drink the beverage. Any lemon that remains in the drink is negligible and does not pose a problem. If the lemon was squeezed into the drink, order another drink without the lemon and offer the first drink to a gentile you know or have it returned to the kitchen.
- Similarly, you may purchase a kosher fish even if it was cleaned with a treif knife provided that the fish you are buying is not the first fish cleaned after the knife was used for non-kosher fish. If you are unsure if this is the first fish or not, you may purchase it and assume that it is not the first as long as at least three kosher fish are being cleaned. As long as the fish has scales on it, it is kosher.
- Leafy vegetables and certain other kinds of produce are presumed to be infested with insects. Infested vegetables and fruit may only be eaten after all of the insects have been removed. If this is impossible, then that food item may not be eaten. Although when one cannot find a forbidden item in a mixture, one need not be concerned about it provided the volume of permissible food is at least sixty times that of the non-kosher food, insect infestation cannot benefit from that halochoh. A whole insect (a beryoh) is never considered insignificant enough to be considered non-existent. Thus, for example, if an insect falls into a pot of cholent and cannot be found, none of the food in the pot may be eaten. Pieces of meat and potatoes that have been inspected and do not have the insect on them may be eaten.
- However, if the insects are not whole, e.g., if they have been puréed, they are considered non-existent (batel) as long as there is a majority of permissible food in the mixture. (The rule of bitul beshishim allowing one part forbidden food in sixty parts permissible food applies to non-kosher food that enhances the flavor of the food, not undesirable insects in food.)
- One is permitted to purposely grind food that may be infested with bugs if all of the following criteria are met:
Therefore, infested wheat may be ground into flour and used.
- Any insects that were in the wheat may have left the wheat as it entered the grinder due to the noise, so it is not certain that the insects are still in the wheat.
- The purpose of grinding the wheat is to make flour, not to crush the insects.
- It is impossible to separate the insects from the wheat.
The same principle is used for wine and fruit juice production.
- Even puréeing food in order to crush any insects in it is permissible as long as it is unlikely that there are insects in the mixture. A food item that is not likely to have insects in it but has not been checked well may be puréed or ground in order to remove any possibility that there is a whole insect. Still, you should glance at the food first to determine whether there are any obvious insects on it. In other words, if a food item is practically impossible to check so thoroughly that you can be unequivocally certain that there are no insects in it, and you have taken steps to minimize the insect population in the food and may have succeeded in removing all the insects but cannot be absolutely sure, you may grind the rest in order to be able to eat the food.
Thus, in places where broccoli, cauliflower or parsley are infested and it is impractical to find and remove the insects, you may prepare the vegetables in a way that can remove the insects and then purée them. For example, you may scrub parsley leaves in soap and water and then place them in a blender in order to make them permissible to eat.
- In order for an insect to be forbidden, it must be large enough for a person with excellent eyesight to determine that it is in fact an insect and not a speck of dirt. If it is necessary to rely on a magnifying glass or other instrument to make the determination, the insect may be eaten. Only the small size serves as grounds for deeming the insect kosher. A well-camouflaged insect that is large enough to be seen against a different background may not be ingested. Furthermore, even if the insect is too small to be identified but is noticeable as a spot that moves, one can be certain that it is an insect and must not ingest it despite its small size. Only movement of a tiny insect indicates a forbidden creature. The location, shape and coloring are insufficient evidence if the insect itself is too small to see with the naked eye. Thus, certain marks on citrus fruit peels that are indicators that there were insects on the peel would not be enough to forbid the fruit. However, because in Israel those spots have been seen to move, one must be concerned that the fruit is infested with insects even if yours don’t move.
- In many developed countries, you will find products with a hechsher in stores that have no kosher section. When planning to travel over Shabbos, it is wise to take a plastic bottle of grape juice and send it in your checked luggage (not in hand luggage, since some airports will dispose of liquids in carry-on bags for security reasons). You can also buy grapes and squeeze them to produce grape juice for kiddush and havdoloh. Some areas have at least one grocery store with a kosher section that will sell kosher wine, grape juice, matzos, candles and other products. Large wine stores in big cities may sell kosher Israeli wines. Rolls or matzos brought along should be placed in a hard plastic container so that they remain whole.
10. Disposable cutlery and dishes may be purchased anywhere. New ceramic plates and pots may also be purchased anywhere and used immediately. Metal, glass and wood items need tevilloh first.
11. If you wish to purchase a utensil that would normally require tevilloh but will be unable to immerse it, you may pay for the item and have in mind not to acquire it as your own. Since it is not yet owned by a Jew, you may use it without tevilloh. Because normal usage makes it appear as if a kinyan has been performed, this should not be a long-term solution. When a mikve, river or ocean becomes available, you should mentally decide to acquire the item, make the necessary kinyon (e.g. hagboho, lifting the item) and immerse it then.
12. Glass can be tovelled in 40 se’oh of snow (330 liters).
Items that do not require a hechsher
13. Coffee, plain tea, sugar, pure cocoa, rice, and natural, whole grains and legumes may be purchased anywhere unless there is a reasonable likelihood that they were imported from Israel.
14. Eggs that look like chicken eggs and are claimed by the seller to be chicken eggs may be bought anywhere.
15. Milk products need special supervision unless the government policy is to verify that all milk sold is cow milk and the dairy companies strictly adhere to the laws to avoid serious penalties that are likely to come from an infraction of the law. Milk bought in the United States, the UK, South Africa and Australia fall in this category. Other EU countries may also fall in this category. When travelling to such places, it is advisable to consult with the local rabbonim regarding this point. Local Rabbonim can often be a valuable source for other manufactured products that are kosher but do not have a hechsher on the label.
16. All unflavored beer and ales produced in the United States, Canada, England, Ireland, Germany, Belgium, The Netherlands and Mexico are kosher provided that there are no additives listed on the ingredient label even though there is no kashrus certification. This applies to alcoholic light and dark beers and non-alcoholic beers. Beware of specialty beers that have additives. Beers from other countries that produce beers using the same methods in Europe and America are also acceptable.
17. American, Irish and Scotch Whiskies are kosher, single malt and blended. However, there may be traces of non-kosher wine in the whisky when the label states that it was matured in a port wine cask. If the label on the whisky bottle mentions usage of a sherry cask, sauterne port, dual casks, French casks, European casks, port finish, maderia finish, dual finish, triple finish, special finish, double matured or triple matured, two wood it may indicate the cask was used with non-kosher wine and some may wish to refrain from drinking it. One who generally avoids consuming food or drink when a kashrus question had arisen even if a definitive lenient ruling has been given and insists on relying only on the strictest standards is advised to choose a different brand that does not have one of the terms mentioned above on the label. However, even if it comes from such a cask, it should not considered treif since it does meet the minimum requirement of kashrus.
18. Pure butter and pasta (flour and water) without additives or flavorings are kosher anywhere in the world.
Items to be cautious about
19. Whenever enzymes, preservatives, flavorings, coloring or any additives are part of the ingredients, a hechsher is required.
20. If you are storing kosher food in a public refrigerator or area where others have access to it, it must be sealed or have a tamper detector. (You can create a tamper detector by taping the item and signing the tape in such a way that were the item tampered you would be able to detect it.)
On the airplane
21. It is permissible to place food under an airplane seat and eat it afterwards.
22. Kosher food may be heated in a treif oven if it is sealed in two complete coverings and it is not known that the racks were dirty with residual non-kosher food or grease. You do not need to assume that the airplane ovens are greasy and dirty. If you know that the racks are greasy or dirty with treif food, you may triple wrap the food to keep it kosher.
Milk and meat
23. You may slice bread with a meaty or dairy knife and eat it with the opposite type of food, if the knife was scrubbed clean and has no grease on it. During travel, standards of cleanliness are often compromised. Make certain that the knife has been properly cleaned.
24. Generally, before eating meat after dairy it is necessary to do three things:
- Wash your hands if you ate the dairy with your fingers.
- Eat a pareve food.
- Drink a parve drink. (If more than a half hour has passed from the time you ate or drank dairy, requirements b and c are not necessary).
If you are traveling and there is no water available, and you ate dairy with your fingers, you may clean your hands by wiping them on a wipe, tissue or cloth or find another way to clean them before eating the meat with your fingers.
25. Bread made of kosher ingredients and baked by a gentile may be eaten. If a bakery also sells non-kosher baked goods, one should not eat its products since oils or milk from the other items may have gone into the trays, making them treif.
Food preparation by a gentile
26. A gentile may heat kosher milk, coffee, tea, cocoa and water.
27. When traveling, you may use non-kosher utensils for kosher food that is not hot. In your own home and generally, you should never use treif equipment with kosher food, even if the food is cold, out of concern that the equipment may accidentally be used with hot food. However, since the circumstance is temporary, you may use treif utensils with cold food when traveling since there is less concern that the utensils will be used with hot food. For example, you can order cereal and milk for breakfast in a non-kosher diner. The bowl and spoon are treif, but the food is kosher. If your appearance is obviously Jewish, however, other Jews who see you may think you are sinning or they may think that the eatery is kosher. Therefore, you should only go into such a restaurant if there are no Jews around or if you are not identifiably Jewish.
28. Food that was cooked (including cooked in a microwave), baked, roasted or fried by a gentile may not be eaten unless one of the following is true:
- The food did not have to be cooked or heated to be eaten, i.e., it could have been eaten raw (e.g., carrots or tomatoes). Although some people swallow eggs raw, eggs are usually eaten cooked and therefore must be cooked by a Jew, not a gentile.
- The food was prepared in a way that would make it an unacceptable course for a royal meal. Potato chips and canned foods are never served in the White House for state dinners; food is always served fresh. Therefore, even if a gentile did the cooking in the can, the food may be eaten.
- The food cooked by a gentile was mixed with a majority of kosher food.
- A Jew placed the food on the fire or lit the fire that cooked the food. (Lighting the fire is not an acceptable solution for Sefaradim). In this case, the food may be eaten even if a gentile did the majority of the cooking.
Smoking and pickling are not considered cooking. Therefore, lox (smoked salmon) and pickled foods may be eaten even if produced by a gentile.
29. If food was cooked by a gentile and became forbidden, the pot in which the food was cooked may not be used for kosher food until it is kashered.
A Guest in a Non-Kosher Home
Avoiding uncomfortable situations because of food
30. When making a social call to a non-kosher home, it is advisable to go when it is not mealtime in order to avoid conflicts. It is also advisable to eat a full meal beforehand so as not to be tempted to eat their food. Furthermore, if you eat first and are asked, “Would you join us for dinner?” you can honestly answer, “I just ate.”
31. One may lie in order to avoid eating food that is treif or might not be kosher. It is best to choose ambiguous words such as “I am on a special diet.”
32. If the food is kosher but dairy, in order to avoid an unpleasant social interaction, one who normally waits six hours after meat may wait five instead.
Terumos and maasros on Shabbos
33. When invited for Shabbos to a home where people are not careful about hafroshas terumos and maasros, you can say before Shabbos, “The food I will separate on Shabbos for terumos and maasros shall be done according to the phraseology found in my siddur and then shall all be terumos and maasros.” On Shabbos, before eating the food on your plate, separate more than 1% of each item that needs separation and say the required berochoh (if tevel vadai) and the nusach for separation.
34. If the utensils you are given to eat with have not been tovelled, ask for ceramic, plastic or paper utensils. If that is impossible or impractical, you may use metal and glass utensils without tevilloh if the owner would not allow you to remove them from the home to be tovelled. If the owner would allow you to tovel the items but there is no mikve around, you should not use them. It is permissible to eat food from a plate that wasn’t tovelled with one’s fingers or a napkin. There is no solution for soup or liquids that need the bowl to hold the food.
35. Food that was cooked in a non-tovelled utensil is still kosher. Only the use of the utensil is forbidden.
36. A person who does not eat kosher but does not violate Shabbos in public is trusted to have immersed the utensil in a mikve if they said that they did so, if he/she knows how to do so. However, if they do not eat kosher, you cannot assume that they immersed there utensils without asking them.
37. Wine from an open bottle that has been handled by a gentile may not be drunk unless it was previously cooked. A Jew who was not exposed to authentic Judaism may handle wines. A Jew who was properly exposed to Judaism and rejected it should not pour wine for another Jew.
Shopping for someone who doesn’t keep kosher
38. If you are asked to go shopping for another Jew and are given a list that includes non-kosher items, you may purchase those non-kosher items if:
- the non-kosher food would be bought by someone else should you refuse; and
- you will be able to minimize the amount of non-kosher products purchased.
For example, if you are given a list of foods to buy at the supermarket that includes chicken, beef, mayonnaise, barbecue sauce, cottage cheese, cereal and potato chips, you should ask yourself what would happen if you refused to go. Would a neighbor do the job? Would your relative call in or send an email order? If the food would come either way, then you may buy the non-kosher chicken and beef as long as you will choose kosher brands of barbecue sauce, cottage cheese, potato chips and cereal. At the end of the day, you assisted your relative in minimizing the transgressions involved in eating and did a mitzvoh rather than an aveiroh.
39. Family members (or people who are close to you like family) whom you know to be trustworthy and who want to please you and offer you food that meets your religious standards but do not keep kosher or Shabbos themselves can be trusted not to deceive you and feed you non-kosher food. However, if they are not knowledgeable in the laws of kashrus, inevitably they will end up erring and making the food treif. Even if your host is not knowledgeable in the laws of kashrus, but you are aware of all the processes carried out in the preparation of your food and have determined that all the steps were halachically acceptable; you may eat the food.
40. If you are invited to a home where your host has promised that all the food served will be prepared according to specified guidelines or a known standard, you may eat the food if:
- all the food in the house of the sort being served is kosher; and
- you trust your host to follow the guidelines exactly and have complete confidence that the host would not lie because of external factors (e.g., were it discovered that the host failed to keep his/her word or that there was non-kosher food in the house of the sort served, he/she would be embarrassed).
However, should there be non-kosher food of the same variety in the house, the kosher food may only be eaten if you see it being taken from its wrapper and seal and prepared for you.
41. There is a subtle difference between clauses 38 and 39. In clause 38, you can eat the kosher meat even though there is non-kosher meat in the home because you have complete confidence that your host wants to meet your religious needs and would avoid any non-kosher food. In clause 39, such confidence needs to be established based on other factors. The host is not known to be particularly concerned about your religious needs but has committed to adhering to them anyway. In such a case, certain precautions are necessary before you can rely on the host.
42. The kitchen of a gentile or non-observant Jew should be kashered before a Jew relies on it. You cannot rely on a person’s statement that the kitchen was kept kosher while you were not around. Any utensils that you wish to use on your next visit without kashering must be stored with a tamper detector. That way, the next time you arrive and wish to use those utensils, you can tell whether or not they have been used. For example, a toaster oven can be sealed in a box or bag with tape crisscrossed over it and then signed over the crisscrossed areas. The box should be taped in such a way that if someone tampered with the tape, it would be obvious.
43. People who keep Shabbos and kashrus can be relied upon. Whatever they say they bought or did in the kitchen need not be questioned.
44. People who violate Shabbos in public or do not keep kosher cannot be relied upon for kashrus issues unless they meet the requirements described above. Such people are suspected of being willing to lie for personal advantage, no matter how inconsequential the gain may seem.
45. Counters: One may use treif counters as long as nothing hot is put on them. Counters are generally kasherable. If the host will be placing hot kosher food on the counter, you can kasher the counter and ensure that while you are staying in the home, no non-kosher hot food is placed on it.
46. Kashering counters: Granite, marble, CaesarStone, wood (if it has a smooth surface), stainless steel and Formica countertops can be kashered by pouring boiling water on them (irui). Ceramic tiles cannot be kashered.
- Remember to first clean the surface well using a rag soaked with a household cleaner.
- Make sure the counter was not in direct contact with hot treif food in the 24-hour period preceding the kashering.
- Pour the boiling water over the entire surface.
- When finished, pour cold water over the surface.
It is best to use an electric water heater that is plugged in and boiling the water as it is being poured over the counter, but any pot of boiling water that was just taken off the fire with a rolling boil is also acceptable. A removable electric hot water kettle is also acceptable. The entire area should have the hot water poured directly on it. Pour it over the countertop systematically to be certain that the hot water reaches all areas.
47. Sinks can be used to wash kosher utensils even if they are treif. You may put utensils down in the sink and use hot water to wash them. If you do not use gloves when washing dishes, the water has not reached a temperature hot enough to cause a problem. Even if the water is hot enough (and you wear gloves so as not to get burned), there are other halachic considerations that make it unrealistic that any problem can arise from washing the dishes in a clean sink.
48. General rules for kashering: Utensils made of metal (soup pots, cutlery, serving utensils, kiddush cups, etc.), plastic, synthetic rubber, Corelle that might have been used with hot, treif liquid are kasherable. First, clean them thoroughly, make sure they were not used for anything hot in the past 24 hours, and finally, completely immerse them in a kosher pot of water that has been heated and is maintaining a rolling boil when the utensil is immersed. The utensil being kashered should be submerged in the boiling water for about fifteen seconds and then rinsed in cold water immediately upon removal. The entire item does not have to be in the hot water at the same time. You can kasher half of the utensil and then reimmerse it to kasher the other part. Just make certain that the second immersion overlaps the part that was already kashered and no part of the utensil was left unkashered. Items should be kashered one at a time.
49. Utensils may not touch each other during the kashering process. For instance, if a set of flatware is being kashered, you cannot take all the knives, forks and spoons and put them in the boiling water together. They have to be placed into the boiling water separately. A suggestion is to tie the pieces of cutlery to a string loosely, leaving seven centimeters between each piece, and immerse the string of cutlery slowly, making sure the water keeps boiling. Remove the string of cutlery and rinse the kashered items in cold water. If tongs are used to grip the utensil, the utensil will have to be immersed a second time with the tongs in a different position so that the boiling water touches the initially gripped area. An alternative method, especially useful for larger pots, is to clean the pot inside and out, leave it dormant for 24 hours, fill it completely with water, wait until the water comes to a rolling boil, and use a pair of tongs to throw in a hot stone or brick that has been heated on another burner. The hot stone will cause the water to bubble more furiously and run over the top of the pot on all sides at once. (Use caution, as the hot water may spray in all directions.) You can also pour boiling water (from a kettle or urn into the center of the pot and have the water spill over the edges. The kashering process is finalized by rinsing the pot in cold water.
50. After the kashering process has taken place, the status of the newly kashered utensils may be changed from dairy to meat or vice versa or to pareve.
51. Drinking glasses made of glass, Duralex, Pyrex or the like may be used for cold or warm drinks without being kashered. Drinks that are too hot to drink in a few swallows should not be put in treif glasses.
52. Kitchen items that cannot be kashered: A toaster oven, sandwich maker, slow cooker (Crock-Pot), enameled pot, or anything made of china or porcelain that has been used for non-kosher food cannot be kashered and should not be used for kosher food.
53. Treif ovens should not be used for kosher food unless the rack is clean and the food is double-wrapped or the oven has been kashered.
54. A non–self-cleaning oven should be cleaned with a special oven cleaner such as Easy-Off and not used for 24 hours. After this time, it should be turned on to the maximum setting for 40 minutes. This is referred to as libbun kal and will kasher the oven, but not the broiler pan or the racks, which come in direct contact with food. The broiler pan can only be kashered with libbun gamur. If you don’t intend to use the broiler, you can simply clean it with oven cleaner and not turn it on to kasher it when you kasher the rest of the oven, as long as the broiler area and oven are two separate systems and the oven vapors do not reach into the broiler area. You can even leave the clean but non-kosher broiler pan in the broiler while baking kosher food in the oven. If vapors from the oven do enter the broiler, however, it, too, must be kashered. If the broiler pan is replaced, the broiler can be kashered in a similar fashion as the oven.
55. Libbun kal is an acceptable way of kashering all parts of the oven that do not come in direct contact with food or with pans that have moisture or liquid on the outer surface. Oven walls that do not touch food are kashered with libbun kal. Racks often come in direct contact either with food (which might have been placed on the rack) or with pans that are sticky or have had some spillage of liquids. Racks therefore should not be kashered with libbun kal.
56. Self-cleaning ovens may be operated on the cleaning cycle and then used. It is better to kasher a self-cleaning oven than to kasher a regular oven in the way described above. Self-cleaning is considered libbun gamur, whereas kashering an oven by turning it to the highest temperature is libbun kal.
57. Microwave ovens without browning elements or convection can usually be kashered. If the walls do not exceed 120 degrees Fahrenheit during cooking, it is certainly cool enough and only have to be cleaned well. To see whether your microwave gets too hot, cook a potato in it for about five minutes and then open the door before it has finished its cycle. Then immediately check the temperature of the ceiling and walls by seeing if you can keep your hands there for 15 seconds. If you can, the oven walls never reached yad soledes bo and have not become treif. Many microwave ovens are able to pass this test. If yours does, just clean the oven walls very well with a cleanser so that the surfaces are clean. Any residual food matter should become pagum from the bleach or cleansing agent. Then put in a new glass tray or cardboard on the bottom.
58. A grill cannot be kashered by just turning on the gas or electricity. Since food is roasted directly on the grill, it requires libbun gamur, which means that it must be heated to a glow in order to be used. This can be done either with a blowtorch (which should only be used by qualified and experienced personnel) or by sandwiching the grates between charcoal briquettes and setting them on fire. Alternatively, the grates of the grill can be replaced. The part of the grill cavity that is level with the grate must also be kashered by heating it to a glow. This is because food is likely to have touched that area during barbecuing. The empty grill cavity must be kashered by cleaning, closing the hood and setting it to broil for 40 minutes.
59. Inserts such as griddles that come into direct contact with food are treated like grills. Therefore, they too would require application of direct heat until the surface glows red. Otherwise, the insert should not used with kosher food. If the grill has side burners, they should be treated like stovetop grates (assuming no food has been placed directly on them).
60. It is easiest to determine that the metal has been brought to a glow in a darkened room. Often, it is more practical to purchase a new grill or rack than to kasher the old one.
61. Stovetops are always self-kashering and do not need to be kashered.
62. Glass-top stoves (e.g., Corning or Ceran electric smooth-top ranges) can be kashered in the area of the burners only. The most practical thing to do is to change the entire glass top. If you wish to kasher the burners, they should be turned to high for 15 minutes. The area in between burners and around the grates cannot be kashered. Since the area beyond the burner is not kasherable, any pot placed on the burner should not touch those areas not kashered. It is advisable to place a disk over the burner area (the disk should not extend beyond the burner area so that it does not reach the part of the glass top that is not kasherable). Any pot placed on the burner can then extend beyond the area of the burner since it will not come in direct contact with the glass top. Nevertheless, if some food inadvertently fell on the unkashered area, it may be eaten. It is advisable to place trivets over the unkashered area so that you have a place to put down the hot kosher pots.
63. A treif dishwasher should not be used for kosher utensils. Technically, dishwashers can be kashered if the interior is stainless steel. The dishwasher must be thoroughly cleaned. A dovor pogem (e.g., cleanser) should be used on every screw, crevice or area that cannot be totally cleaned.
64. After waiting 24 hours from the last time the dishwasher was used for treif, run a complete cycle with soap. If the dishwasher heats its own water, you have to make sure that the water in the kashering cycle reaches boiling; this is difficult to verify. There are numerous halachic concerns regarding the kashering of dishwashers. One should only consider kashering a dishwasher if one of the following is true:
- Twelve months have passed since the last time the dishwasher was used and not kashering it would entail a great loss of money.
- A particular crisis can be avoided if the dishwasher is available. In such a case, after waiting 24 hours since the last time the dishwasher was used, the kashering process should be carried out three times. Only then may the dishwasher be used.
65. A hot water urn or teakettle may be used without kashering. You may presume it was used only for water and is thus permissible, unless you know for sure otherwise.
 The only concern is that one might end up eating the whole insect; halochoh is not concerned with the flavor of the insect being absorbed by the kosher food, if the general consensus is that eating insects or their flavor is unappetizing.
 א”צ ששים בזה כיון שאינו נותן טעם לשבח, ולכן בטל האיסור ברוב. ואע”ג דמין במינו עכ”פ צריך ששים מדרבנן אע”פ דאינו נותן טעם לשבח, י”ל דשאני דברים מאוסים שאינם נותנים טעם לשבח בשום דבר משא”כ מין במינו דחז”ל גזרו מינו אטו אינו מינו שלא יבואו להקל ברוב אילו נתערב מין במינו היכא דנותן טעם לשבח.
ודע, דביצי תולעים ושרצים אף דלדעת רוב הפוסקים אסורים באכילה מה”ת, מ”מ אם נתערבו בדבר אחר ולא ניכרים בטילים ברוב ואין להם דין בריה.
 בפמ”ג יו”ד סימן צ”ט במ”ז סק”י דאם נטחן שלא כדין בכוונה כדי לבטל את האיסור שבו, כל המאכל נאסר עבור מי שטחן וגם למי שנטחן עבורו. אכן אם מטרת הטחינה לא היתה כדי לבטל את האיסור, המאכל מותר גם עבור הטוחן עצמו וכ”ש עבור למי שנטחן עבורו למרות שלא היה לו רשות לבטל את האיסור לכתחילה.
 עיין ט”ז סימן צ”ט סק”ז ופת”ש שם סק”ד.
 עיין יו”ד סימן פ”ד סעיף י”ד וש”ך שם סק”מ בשם תרה”ד.
 עיין בינת אדם לח:לד, עה”ש יו”ד פד:לו ושו”ת שבט הלוי ז:קכב, שמירת שבת כהלכתה פ”ג הערה לז,
 Chabad rabbis generally do not rely on this halachic opinion. They will use cholov Yisroel or nothing. The Chazon Ish and Rav Moshe Feinstein permit usage of cow milk that has not been milked under the supervision of a Jew as long as the government regulations forbidding anything other than cow milk are strictly enforced and a significant penalty would be imposed upon a company that failed to follow the regulations. So when researching whether a locale qualifies the halachic requirements for milking without Jewish supervision, a chabad rabbi may not be your best source for this issue.
 Rav Moshe Feinstein, for example wrote a response permitting these whiskies (Y.D. 62) and prefaced the teshuvoh by stating that he himself avoids such whisky unless he is with a group of people who expect him to make a lechaim and offer a berochoh to the group. On such occasion he will drink a small amount so as not to appear holier than the others. Should a person be in a situation in which he is offered such a whisky and it would be socially unacceptable, offensive, jeopardize a business deal or other important opportunity were one to refuse, in my opinion one may drink such whisky.
American single malt whiskeys are prepared in new oak casks and do not pose a kashrus issue. Americans spell whiskey with an e and the British and Irish spell it “whisky”. Therefore, the discussion of port wine casks mostly applies to whisky.
 חשש סכנה אינו אלא על אותו דבר ממש שהצביעו עליו חז”ל. והם דברו על מטה ממש שעל הארץ. לכן נראה שכסא באוירון המשמש גם לשינה אינו על הארץ ואינו מטה ממש, ואין צריך לחשוש לאכול אוכל המונח שם.
 A smaller, lighter pot is easier to control, and a smaller pot doesn’t take as long to reach a rolling boil. Some people try to use large pots since they hold a lot of water. Large pots of hot water, however, can be more dangerous, are bulky and allow less control pouring the water exactly where you want it to go. Furthermore, the larger the pot, the longer the water takes to reach a boil.
 An electric kettle usually has a cut-off switch that turns off the power as soon as the water starts to boil. If that cut-off switch is broken or if you have figured out how to bypass it, and the water continues to boil until the kettle is removed from the base, that kettle is perfect for kashering because the water gets so hot that one can hear it boiling while pouring it over the sink and counters. Often, the cut-off switch can be bypassed by keeping the lid of the kettle open. The water will continuously boil and can be used to kasher your countertops.
Consider all water kettles kosher unless you know they have had something treif on or in them when they were hot.
 Some people place pizza or other food directly on the racks on occasion. If those foods were not kosher, the racks would need libbun gamur to be used for kosher food. The only practical way to perform libbun gamur on the racks is to place them in a self-cleaning oven during a self-cleaning cycle. If you always place pans on your racks and there is no spillage of food onto the racks (if that is possible), you can leave the racks in the oven and libbun kal (which will be defined later) is sufficient. If there is an occasional spillage and food is not regularly placed on the racks, libbun kal is acceptable bedeieved for food cooked in that oven.
In other words, if you are the one responsible for kashering, you should make sure to do libbun gamur. Once libbun gamur has been done, you can freely use the oven without restriction. However, if someone else kashered it with libbun kal and you know that most of the time the rack was used with a pan or some other separation between the food and the rack, then you can rely on the kashering process of libbun kal and eat kosher food cooked in that oven. See Shulchan Aruch O.C. 451:6, where the various opinions are mentioned. The Ramo is concerned about even an incidental absorption of flavor, whereas the Mechaber rules that one only need be concerned about the way the item is used the majority of the time. According to the Mechaber, the appropriate kashering method depends on how the utensil is used the majority of the time. Although the halochoh according to Ashkenazim follows the Ramo, that is only regarding how one should kasher lechatchiloh. In a situation, however, in which the racks were already kashered applying the rules of the Mechaber, and the oven was used by other cooks to prepare food, even an Ashkenazi may eat food that was cooked in such an oven. Were the Ashkenazi be the one to use the oven and bake in it, he should not rely on the kashering process that is appropriate only according to the opinion of the Mechaber. (This is true assuming that you follow the minhag of kashering only a utensil that is eino ben yomo. If you are unsure if the item is ben yomo or there is some extenuating circumstance permitting the kashering of a ben yomo, all opinions agree that the kashering method must match the method in which the flavor went into the utensil in the last 24-hour period.)
כתב המחבר בהלכות פסח סימן תנ”א ס”ו כל כלי הולכין בו אחר רב תשמישו הלכך קערות אע”פ שלפעמים משתמשין בהם בכלי ראשון על האש כיון שרב תשמישן הוא בערוי שמערה עליהן מכלי ראשון כך הוא הכשרן. וברמ”א שם ויש מחמירין להגעיל קערות בכלי ראשון וכן הוא המנהג. ובגר”ז כתב (תנ”א סכ”ז) ולענין הלכה יש להחמיר לכתחילה כסברא האחרונה וכן נוהגין ואין לשנות עכ”ל. וע”ש בסכ”ח. ובמ”ב ס”ק מ”ז כתב להדיא דבדיעבד סמכינן אדיעה ראשונה וכ”ד המקור חיים. ומש”כ דאם הוא בן יומו גם המחבר מודה לרמ”א, כ”כ המ”ב שם ס”ק מ”ו וז”ל אם ידוע שתוך מעת לעת השתמשו בו בחמץ בכלי ראשון ממש אע”פ שעיקר תשמישו תמיד הוא ע”י עירוי או בכלי שני צריכין הגעלה בכלי ראשון אלבא דכו”ע ואם ע”י האור צריך ליבון עכ”ל. ומלשון המ”ב משמע דאם הוי ספק אי הוי ב”י ס”ל למחבר דאזלינן בתר רב תשמישו, וצ”ע דלכאורה הוי ספק דאורייתא ועיין בחזו”א דעמד ע”ז (סימן קכ”ב סק”ד) וכתב דנראה דגם בספק יש להחמיר ובעינן ידוע שלא נשתמש תוך מעל”ע שימוש החמור ואף שהוא מועט מ”מ לא שייך כאן למיזל בתר רובא דאין שימוש המועט מקפח שימוש הרוב, וכ”ה ברמ”ע שם דספק הוי ספיקא דאורייתא אלא שבסוף דברי הרמ”ע לא משמע כן, ואפשר דבעינן שיהא לבו מסתפק בדבר וסתמא לא חיישינן כיון דלא שכיח עכ”ל. הרי היכא דלבו מסתפק בדבר ס”ל דהוי ספיקא דאורייתא ולכאורה ממ”ב משמע דכשלבו מסתפק ס”ל למחבר דאזלינן בתר רב תשמישו אם לא דנימא דהמ”ב מיירי בסתמא ודוחק לומר הכי.
 In an office where there is one microwave for all the employees, and som employees bring in non-kosher items, one may use the microwave if it clean and the walls do not get hot (yad soledes bo) and your kosher food is placed on a different base than that which was used for the non-kosher food. By bringing your own Styrofoam or glass plate as a base, to use for your kosher food, you can use the clean microwave even without covering the kosher food.
 The trivets may touch the unkashered area. Since the trivets and unkashered area are dry, no flavor passes between them. The pot is only touching the trivet. It is important to avoid a situation in which hot liquid connects the pot to the trivet and the trivet to the unkashered area.
 לענין הגעלת מדיח כלים מטרף עיין אג”מ יו”ד ח”א סימן מ”ג ח”ב סימן מ”ו וח”ג סימן כ”ח דאפשר להגעיל אחר יב”ח בהפסד גדול ואפילו תוך יב”ח בשעת צורך גדול אם מגעיל ג”פ.