Testing of vanilla ice cream bought from 17 Dunedin dairies showed that five of the cone ice creams were contaminated with E. coli bacteria at levels far above those permitted by the New Zealand Food Safety Authority.
An ice cream which had by far the highest level of E. coli among the 17 samples was also found to be contaminated with the staphylococcus aureus micro-organism.
In a further twist, that particular ice cream - and another which was also found to have E. coli - came from stores which had received an "A" grading by the Dunedin City Council environmental health department.
Kim said finding bacterial contamination in nearly a third of the samples was "scary".
Her findings are being highlighted in a research project she has created as part of the 2009 Aurora Otago Science and Technology Fair, which is being held at the Otago Museum later this week.
More than 270 science exhibits produced by pupils at 30 Dunedin and Otago schools can be viewed by the public from tomorrow until Sunday at the museum's 1877 Gallery.
Prof John Tagg, a University of Otago microbiologist and a science fair judge, said the E. coli contamination in these cases had ultimately come from the human gut and probably reflected inadequate hand washing or other hygiene controls.
The staphylococcus contamination was likely to result from a shop staff member touching his or her nose and later touching either the scoop or the ice cream.
The E. coli infection was unlikely to kill anyone but some bacteria in the E. coli family produced toxins which could make people extremely ill.
The test results highlighted the "absolutely vital" need for good hygiene, he said.
His son, Andrew Tagg, an Otago graduate, and also a judge at the fair, said the practice in some shops of allowing ice cream scoops to sit in warm, "dirty" water for much of the day could result in micro-organisms growing in the water and on the scoop.
Kim's research showed that scientific methods, even when applied by a young scientist, could produce important results, Mr Tagg said.
He noted that an earlier high school science experiment conducted by two 14-year-old girls at Pakuranga College, Auckland, in 2004, had detected unexpectedly low levels of vitamin C in the juice drink Ribena.
The giant multinational company GlaxoSmithKline was subsequently fined $217,500 in the Auckland District Court in March 2007 after it admitted having made claims about vitamin C in Ribena that were on some occasions false and on other occasions misleading.
Dunedin City Council team leader for environmental health, Ros MacGill, said the department would check the methodology used in the tests but emphasised the "unfortunate" findings were not being taken lightly.
The hygiene issues, which had long been emphasised by the department, were likely to be highlighted again in the next issue of a regular newsletter which would soon be sent to food operators, Ms MacGill said.
Dr Michael Schultz, an award-winning senior lecturer in the Otago University department of medical and surgical sciences and a consultant gastroenterologist at Dunedin Hospital, said the ice cream research had been undertaken by his daughter, Kim.
However, advice on some matters had first been gained from the university microbiology and immunology department, the bacterial cultures had been grown in his laboratory and Kim's identification of E. coli colonies had been confirmed by a university microbiologist.
