The defence in Judge Nkola Motata's drunken driving trial on Tuesday raised queries about several aspects of the procedure a Johannesburg Laboratory used in testing blood samples for alcohol levels.

In the Johannesburg Magistrate's Court during the cross examination of Logan Govender, a former chief forensic analyst at the laboratory, defence advocate Danie Dorfling raised questions about the effects different temperatures could have on blood samples being tested.

Govender said the laboratory had a policy to keep samples in temperature controlled storage of four degrees.

He said when samples arrived at the laboratory they would initially be kept at room temperature in a trunk at the reception until being sorted and put into cold storage — by latest at the end of the day.

Responding to questions by Dorlfing, Govender said higher temperatures could cause less inhibition on alcohol forming in the samples during a fermentation process.

He said however, tests tubes where samples were placed contained sodium fluoride. The sodium fluoride inhibited enzymes from forming and creating alcohol from forming.

Dorfling also pointed out a discrepancy between the date of origin of the sample on the police receipt and sample label.

A label on the sample recorded blood as having been drawn on 6 January 2007 — however a case number on the police receipt recorded the blood sample as coming from December 2006.

Pretoria High Court Judge Motata is on trial after crashing his jaguar into the perimeter wall of a Hurlingham property on 6 January 2007, allegedly while drunk.

Sapa