Kosher Food Packaging for Deliveries

General

1. Meat, and, in general, other food that is out of a Jew's sight for a certain amount of time no longer retains its status as Kosher. This fundamental principle is called Basar SheNitalem Min Haayin, and it can be applied to cases when a Jew sends food to another Jew using a non-Jewish delivery person.
2. The concern is rooted in our inability to know the motivations for the non-Jews to possibly switch the Kosher food for non-Kosher equivalents. We thus would prefer the food to be watched by a Jew from the time of its production until its consumption.
3. In order to assuage our need for the food to be as if it is watched constantly, we rely upon either Simanim (clear symbols), a Jew being able to identify this object as being exactly the piece of food that they knew to be Kosher previously, or, most significantly, Tzarur v'Chatum - ensuring that the meat or other food is wrapped, packaged or sealed (either once or twice, depending on the situation.
4. This concern applies to rich delivery persons as well as it does to poor ones.
5. Leaving a deposit of food with a non-Jew is considered with the same analysis as cases with a non-Jewish delivery person.

How Many Seals are Needed?

There is a disagreement among Medieval Rabbis about how to understand a seeming contradiction in Rav's opinionregarding the number of seals which are needed. The Shulchan Aruch holds that if the food presents Kashrut concerns on a DiOrayta level, then two seals are needed. However, other food would only require one seal. The Shulchan Aruch nevertheless cites other opinions which are more stringent when it comes to which situations require two seals.

Types of Effective Seals

Using Unique Knots

1. Two uncommon knots which are tied around a package could be considered two seals, however two regular knots would not count as two seals. Some say, however, that if the first knot is uncommon, then even if the second knot is common the combination of the two would be considered two seals.
2. If you have a unique seal on a package of some kind (which is distinct from the usual way to seal the type of package in question), then adding a knot on top of the box is sufficient to establish this package as doubly-sealed.

Sealing Bottles Effectively

1. Bottles that are closed strongly with a cork or another type of cap which cannot be opened without a special tool (bottle-openers, corkscrews, etc.) are considered to have one seal. Adding a clay seal on top of the cork would be considered the second seal.
2. Bottles for drinks that do not need two seals (milk, juice, lemonade, etc.) may be sent with a non-Jew with only a single seal.
3. Some poskim hold that you can seal a bottle loosely and then fasten a clay seal on top of that in order to render its one seal. However, some poskim recommend being stringent.

Wine Delivered by a non-Jew

1. In general, there is a disagreement about whether wine would require one seal or two. However, some poskim maintain that nowadays everyone would agree that wine always only needs one seal.
2. If you want to send cooked wine or wine which is flavored with honey or another similar additive, then perhaps you will only need one seal, as the wine is extra identifiable. However, some suggest that this leniency would only apply if the delivery person is informed about the uniqueness of the wine. If the delivery person is not aware of the uniqueness of the wine, then there would not be any additional factors in this situation which would inhibit the delivery person from tampering with the wine. However, after the fact, if the non-Jew did not know the state of the wine when they were delivering it, then the wine is still considered Kosher according to some poskim.

Meat Products Delivered by a Non-Jew

1. If the shape of the slices of meat are distinguishable due to a specially shaped cut or a there is a special string strung through the meat which you know as a sign of Kashrut, then you can eat such meat when it is delivered to you by a non-Jew.
2. If a non-Jew delivered you several pieces of meat and some had Kosher-signs and some did not, if there is reason to think that some were switched then the ones without Kosher-signs are forbidden. This would be true even if all the pieces of meat in question were in a bag together with a single seal.
3. If you got a piece of thigh meat delivered by a non-Jew, and it is cut in such a way that makes it clear that only a Jewish butcher could have slaughtered this piece of meat (because the sciatic nerve is removed seamlessly) then no seal is needed, because this is an absolute sign of Kosher meat.
4. Consider a case where someone sent a bird with a non-Jewish messenger to get slaughtered in a Kosher way. If the delivery person comes back with a slaughtered bird, it is okay to eat if you can identify something unique about the bird which assures you that this bird was yours previously.
   1. If, however, you send the non-Jew with money for the Shechita, or the place of Shechitta is very far away, then it is not okay to eat the bird that he the delivery person comes back with, as he would have great motivation to slaughter the animal himself, pocket the money, and avoid the long travels.

Butter Delivered by a Non-Jew

1. After the fact, you can eat butter delivered to you by a non-Jewish messenger even if it doesn't have any seals.
2. However, if there is a reason to expect that there are problems more severe with the butter than just ‘Milk of a non-Jew,’ then the butter must have a seal for it to maintain its Kashrut when it is sent with a non-Jew.

Bread Delivered by a Non-Jew

1. In places where the Jews eat bread made by non-Jews, then some say it is permitted to eat bread sent to you through a non-Jewish delivery-man with no seals. However, some disagree with that position.
2. If the bread in questions seems to have things inside it which are not permitted to eat if they were delivered to you by a non-Jewish delivery man, then the appropriate number of seals are required according to everyone.