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Saturday, 26 July 2014

The Lion, the Goat and the Yam Test for Prospective Food Safety Managers

You very likely have heard this old Nigerian riddle but not as a food protection aptitude test. All good food safety managers should be able to solve this riddle. Your yam and goat, are they safe? With some modification, clarification and added challenge to appease critical minds, here is the riddle:

A man has to cross a river with his lion, goat and tuber of yam in a canoe. The canoe needs to take at least two of the passengers for balance each time but cannot hold more than three (the yam has sufficient weight as a passenger - huge yam). The lion has no interest in the man or the yam as food but finds the goat to be irresistibly appetizing. The only reason the goat is spared is because the man gets between and separates them every time the lion goes for the goat. The goat sees the yam and feels the same irresistible  urge to consume it. The man and the lion are of no interest to the goat. The man also protects the yam from the goat. However, with him having to do the paddling, the protection intervention is not possible in the canoe. How should the man get his yam, goat and lion safely across with no consumption casualties?

Note: Like certain situations in food safety and quality management, there is no opportunity for "corrective action".The challenge demands SSQA kind of strategic and preventive action. 
Posted by Felix Amiri
Felix Amiri is currently the chair of GCSE-Food & Health Protection, and a sworn SSQA advocate.


  1. Trip 1 : Man & Goat to the other side
    Trip 2 : Man & lion (when getting to the other side man loads goat again and goes back with the goat)
    Trip 3 : man drops off goat and takes the yam ... then goes back
    Trip 4 : Drops off the yam where the lion already is
    Trip 5 : Goes back and picks up goat for the second time .
    Trip 6 ( The final ) : Goes back with the goat to where the lion and the Yam already are...

  2. Man, Lion, and Yam on first trip across, drop off Lion
    Man and Yam return to other side, drop off Yam, Pick up Goat
    Man and Goat across, drop off Goat, pick up Lion
    Man and Lion return to other side, pick up Yam
    Man, Lion, and Yam across, all unload and safely across.

  3. @Shuhaib: Trip 5 did not meet the required minimum of 2 passengers.

  4. @John: The 5 trips strategy appears to have done the job effectively and efficiently. All requirements met, all across with goat and yam preserved in tact. I wonder if anyone can beat this strategy.