To be accepted as kosher, certain foods which are completely cooked by a non-Jew (bishul akum) may not be eaten, even if the foods are kosher and are cooked with kosher utensils. Ruth Pretty calls on a local Rabbi to sanction the food for the times she has catered Jewish events in Wellington (this was for a Bar Mitzvah). Foods that generally come under the category of bishul akum are:

Foods that cannot be eaten raw, such as meat or grains. (This excludes foods that can be eaten either cooked or raw, such as apples or carrots.)
Foods that are considered important, "fit to set upon a king's table." There are various opinions regarding what are considered "royal foods."

The key is for the Rabbi to participate in the cooking in a meaningful way in order to render the food kosher. If a non-Jew cooked the food alone, without Jewish participation, the food and utensils are not regarded as kosher.

These photos were taken with 35mm film and I can't help thinking they have a natural and organic feel, resonating well with the Koshering.