Processed Food without Hechsher: Is It Kosher?
 
If a processed food does not have supervision/hashgacha, here are some issues to consider:

• Ingredients;
• Utensils/processing equipment;
• Bishul akum/“prestigious” foods that require Jewish involvement in the cooking;
• Heating system (recirculated steam?);
• Heter for milk without being supervised - which conditions and countries can be relied on;
• Non-food ingredients (lubricants, preservatives, emulsifiers...);
• Reliability of the producer;
• Is the non-kosher ingredient batel/nullified?
  • ownership (Is the food's producer or owner Jewish?)
  • intended consumer (Is the food being produced specifically for Jews, or is it for the public and Jews are some of the customers)?
  • Was the non-kosher substance added intentionally?
  • Does the non-kosher substance have flavor?
  • Was the non-kosher substance added for flavor?

A hechsher/kosher supervision is not needed on:

• Beer made in the US (and sometimes in other countries).
• Nuts (dry roasted) without additives.
• Olives--assumed to be kosher unless mixed with ingredients that may be non-kosher, such as:
  • Vinegar (sometimes made from grapes).
  • Non-kosher chemical preservatives (in commercially sold olives).
  Note In open markets in which olives are sold in bulk, you may eat olives after checking the ingredients.
• Olive oil (extra virgin).
• Pure fruit juice NOT made from concentrate (such as orange or pineapple juice) does not normally require a hechsher (except for grape juice, which always requires a hechsher!).
  Note Juices from concentrate might have kashrut problems due to the vats in which they are cooked or pasteurized. If you can verify how the juice was processed and that there are no kashrut problems, you may use the juice without a hechsher. There may also be problems with juice made from fruit or vegetables which were grown in Eretz Yisrael, due to orla, shmitta, teruma and maaser.
• Scotch whiskey--even where it might have been aged in sherry casks.
  Reason Any sherry would be nullified as less than 1/6th. 
  Note Other types of whiskey may not be kosher because:

  • Glycerine may have been added;
  • The whiskey may have been owned by a Jew during Passover in a previous year; or
  • Milk, or alcohol derived from milk, might have been added.
• Sugar (confectioner's) needs kosher supervision only for Passover. Regular sugar never needs kosher supervision (currently).
• Unprocessed foods such as
  • Raw fruits and vegetables (but might need to be checked for insects), and
  • Water, but some unfiltered tap water might have tiny creatures in it which make the water non-kosher.

 

Cheese/Gvinas Akum
 
Gvinas akum is cheese which has been made by non-Jews and by rabbinical prohibition is only kosher if a Jew was present during the cheese making OR if a Jew put the rennet into the milk.
Note If a Jew owns the milk before processing, a non-Jew can add kosher rennet as long as it can be confirmed that the rennet is kosher, even if no Jew is present during the cheese making.
 
Origin of the Problem: Chazal were concerned that the rennet used to make cheese might be from a non-kosher animal or even from a kosher animal that had not been slaughtered properly. Shulchan aruch says that even cheese curdled by kosher plant enzymes (such as fig branch sap or substances from certain thistle plants) are subject to the takana.
Note Gvinas Akum is not related to chalav yisrael; they are separate halachot.

Note Even rennet-less cheeses need hashgacha (religious supervision), but some non-hard cheeses may be an exception. Ask a rabbi.