question:  Why is Kolin so worried about the purple berries?
context: Despite sour feelings for the space service of Haurtoz, steward Peter Kolin had to admit that casualties might have been far worse. It may be useful to discover temporary sources in this area of natural foods." Lack of complete loyalty to the state was likely to result in a siege of treatment that left the subject suitably "re-personalized." "You will scout in five details of three persons each," Chief Slichow said. "Every hour, each detail will send one person in to report, and he will be replaced by one of the five I shall keep here to issue rations." Kolin found himself in a group with Jak Ammet, a third cook, and Eva Yrtok, powdered foods storekeeper. Since the crew would be eating packaged rations during repairs, Yrtok could be spared to command a scout detail. Chief Slichow emphasized that the keepers of rations could hardly, in an emergency, give even the appearance of favoring themselves in regard to food. To reach their assigned sector, they had to climb a forbidding ridge of rock within half a kilometer. Only a sparse creeper grew along their way, its elongated leaves shimmering with bronze-green reflections against a stony surface; but when they topped the ridge a thick forest was in sight. For all Kolin could tell, he and the others were isolated in a world bounded by the rocky ridge behind them and a semi-circle of damp trees and bushes several hundred meters away. "Be a job to find anything edible here," grunted Ammet, and Kolin agreed. Yrtok paused to examine some purple berries glistening dangerously on a low shrub. Fifty meters away, Ammet sat beside the bush with the purple berries, utterly relaxed. As he reached her, whatever Yrtok was examining came to life and scooted into the underbrush with a flash of greenish fur. "It's dangerous. At first, Kolin saw no way, but then the network of vines clinging to the rugged trunk suggested a route.
output:  They may have had adverse effects on his crewmates' mental state.
options:  He expected them to be a different color.  They may have had adverse effects on his crewmates' mental state.  The cook thinks that they are dangerous to eat.  If they are not edible, they will not have any food to bring back with their report.