Even though foods manufactured and sold in the USA are required to list their ingredients, a simple reading of ingredients may not be sufficient to determine the kosher status of some foods because:

• They are not required to list “manufacturing aids” such as oil, and
• The manufacturing equipment may be non-kosher.

 

Blood spots even from unfertilized eggs may not be eaten; the custom is not to eat that entire egg. Blood spots in fertilized eggs render the entire egg non-kosher.
 

Cold, spicy/charif, solid food (with no liquid) does not transfer gender UNLESS it was under pressure, so simply sitting in an opposite-gender or non-kosher container does not have any effect.

     Cold, spicy/charif, solid food (with no liquid) does not transfer gender UNLESS it was under pressure, so simply sitting in an opposite-gender or non-kosher container does not have any effect.
Note You may l'chatchila eat spicy/charif food if it is on a glass plate, even if it is under pressure,
     Cold, spicy/charif, liquid food is kosher only if it sat less time than needed to become cooked.
Example
     You ate cold (less than 120° F, or 49° C) spicy/charif food of one gender on a cold plate of the opposite gender:
Solid Food
      If the cold, spicy/charif food is solid, the food is kosher l'chatchila. But you should only do this ad hoc and you should not eat it with a fork.
Liquid Food
      If the cold spicy/charif food is liquid but it is in contact with a utensil of the opposite gender for less time than it takes to boil, it would be kosher but, again, you should only do this ad hoc.

The purpose of the rabbi at a wedding is to ensure that the extremely detailed wedding halachot, as set out by the Shulchan Aruch, are followed correctly. If not, the wedding might not be kosher.
 
A Jewish marriage includes: a written document (ketuba); a financial transaction (ring) in front of two kosher witnesses; and physical intimacy. 
 
Witnesses
 

• The witnesses must be shomer Shabbat Jewish men.
• The bride and groom should confirm verbally that these are the two (and the only two) witnesses that they want.  

 
Ring

• The groom must confirm that he acquired and owns the ring.
• The groom must say Harei at mekudeshet li ...  to the bride and place the ring on her (index) finger.

 
Ketuba

• The ketuba must be kosher.
• Before the chuppa, someone (anyone, including women) must fill in (no safrut is required for this):  the Hebrew names of the bride and groom; the date the wedding is taking place; the wedding location (city, etc.); and that a kinyan was made.
• The ketuba must be signed by two kosher witnesses.

All beverages that contain alcohol made from any of the five grains (wheat, barley, oats, rye, and spelt), and which were owned by a Jew during the Passover holiday, are not kosher.

Rabbinic guidance is recommended when using a river, lake, or spring as a mikva due to:

• Problems of mud, dirt, or sand, and
• Difficulty in checking if the person is fully underwater,
• It might not be a kosher mikva.

Food soaked in brine, vinegar, or any spicy liquid for long enough to be cooked if heated on a burner or in an oven will absorb or transfer gender or non-kosher status from/to any utensil used with it.

You may microwave a dairy food in a meat (or meat food in a dairy) glass (or Pyrex or Corelle) utensil. Even if the food gets hotter than 120 degrees, the food and utensil are still both kosher. (This is not true if placed in a conventional oven!)

Pot lids are treated as if they are utensils.

A non-spicy/non-charif liquid or food with any liquid (enough to pour, but that may be even one drop) that sits for 24 hours or more will transfer gender or non-kosher status to its container.
Situation Dairy or meat liquid-containing food is in pareve container.
StatusContainer will become dairy or meat (regardless of intention). 

WERE BOTH FOODS LESS THAN 120° F?
YES

ARE BOTH FOODS SOLID?
YES
Status If you can separate them (there are no cracks in the meat), both foods are kosher.  Consult a rabbi.
What to Do

• If one or both of the foods were already cooked, separate them and wash with soap and water (if possible).
• If it is not possible to separate them, just cut off the thinnest slice possible from each surface of each food which had been in contact with the opposite gender food and you may use the food.

NO
SOLID FOOD FALLS INTO LIQUID FOOD OR LIQUID FOOD FALLS ONTO SOLID FOOD
Status If both foods are cold and you can separate them (there are no cracks in the meat), they MAY be kosher.  Consult a rabbi.
 

• Both foods are non-kosher if they cannot be separated.
• If you can separate them enough that one becomes less than 1/60th the volume of the other:
  • The larger food is kosher.
  • The lesser one is non-kosher. 

What To Do

• Once the two foods are separated, wash or otherwise remove the smaller food from the larger one.
• If not possible, cut off the thinnest slice possible and you may eat the remaining food.

Note If there are cracks in raw or cooked meat, and if you can clean off enough of the dairy spill so that the remainder is less than 1/60th, it may be kosher--ask a rabbi.
 
LIQUID FOOD FALLS INTO LIQUID FOOD
Status Both liquid foods are non-kosher.
Exception If one liquid food is less than 1/60th the volume of the other one, the mixture is kosher.
Note If non-kosher wine is involved, see below.
 
SOLID FOODS, ONE OR BOTH ARE HOT
Status If one (or both) of the foods is hotter than 120° F, both foods are non-kosher.
Exception If one food is less than 1/60th of the volume of the other:

• The larger-volume food may be kosher (consult a rabbi).
• The smaller-volume food remains not kosher.

Possible Exception  If the food on the bottom is cold and thick, consult a rabbi.

If either food is spicy, see above.
If any combination (solid and liquid; solid and solid which are in any liquid; or liquid and liquid) of dairy and meat were soaked together for 24 hours or more, even if cold, they are all not kosher.
Exception In any of these three cases, in which one is less than 1/60th the volume of the other:

• The larger food is kosher.
• The lesser one is non-kosher.

Note You must remove the smaller food from the larger one and wash off the larger one, if possible. If you don't know how long the foods soaked together but it may have been less than 24 hours, you may use the foods.