Another theory is that kosher animals were healthier to eat than non-kosher animals.
Some have also suggested that science supports many of the intuitions found in Kashrut, albeit not in all specific kosher laws.
Note that many foods meet the U.S. FDA standard for "Non-Dairy" while they do not meet the Jewish standard for "Pareve" and are labeled with the "D" next to the kosher symbol.
Reading the label can, however, identify obviously unkosher ingredients.
Kosher and halal butchers deny their method of killing animals is cruel and expressed anger over the recommendation.
Before there were certification agencies, kosher consumers would read the list of ingredients to determine if a product was acceptable to eat.
Some authorities have ruled that any unnecessary suffering by the animal can render otherwise kosher meat treife.
Similarly, many keep a degree of kashrut at home while having no problems eating in a non-kosher restaurant, or will follow leniencies when eating out that they would not follow at home.
Store-bought foods can be identified as kosher by the presence of a hechsher (plural hechsherim), a graphical symbol that indicates that the food has been certified as kosher by a rabbinical authority.