According to Dr. Mercy Ifeanacho of the Biochemistry Department of the University of Port Harcourt : "The whole essence of processing the bitter variety is to reduce the cyanide level, which is the implicated toxic substance. In trying to do this, we engage many processes, which depends on steps, sequence and time.
"In fermenting cassava, you peel grate and dewater. While it is being dewatered, fermentation takes place. When we are talking about it we should realise those micro organisms are involved. In fermentation of garri, serial fermentation is involved.
"Some group of bacteria starts the work and lactic acid is increased during this process. This will reduce the P.H. level of the garri. Another set of micro organisms then takes over and further increase the acid level reducing the P.H. The length of time will determine the quantity of cyanide that will be removed from the cassava.
"That is why when you ferment garri for a shorter time; there will be higher cyanide retention. The level of cyanide retention is further reduced, after fermentation during roasting of product on fire. There is a chemical process that takes place between the oil added during roasting of garri and any cyanide present. The presence of red oil actually neutralises the toxic effect of cyanide in garri so red garri is safer than the white one."
On whether fruits and vegetables flush out cyanide from our system, Ifeanacho saids it was possible, as vegetables and fruits are loaded with vitamins and minerals.
Accordingly, "the elemental nutrients are known to contain some kind of anti-oxidants. I am not sure of the digestibility of cyanide, but foods high in fiber have a way of pulling waste out of the body. That way it will not allow cyanide to stay longer in the body to cause further harm to the body."
Giving tips on how to identify garri not properly processed properly. "Traditionally and locally, when people want to buy garri from the market, there are ways of testing for good ones. For someone that is economically minded, like hoteliers and owners of restaurants, they will rather buy ones that are starchy because it tends to give more volume. For home consumption, one should buy garri that is properly fermented. It will show in the colour of the product. Garri that is properly processed is not that bright, just like you have Ijebu garri.
"Taste is another indicator of the level of cyanide in a product. If you taste it and it is sweet, that means the cyanide content is high. When it is sour, it is an indication that it may be properly fermented. If you press and it comes out free, it means it contains less moisture and the cyanogens are lower in low moisture products. People should watch out for poorly processed cassava products as they can be very toxic."
Also speaking on this, Dr. Ezirm said food sources high level of sulphur are good at holding on to the cyanide and taking it out. Also, vegetables that contains allicin compound found in onions and garlic family are also good at this, while pointing out that all vegetables and fruits that contain anti-oxidants help the body build up immunity and clear free radicals like cyanide.
"Fruits high in lutein, like banana, should be eaten regularly in areas where garri is highly consumed, as they help protect the eyes against macular degeneration," she said, while advising that people who "love to swallow should also look for alternative sources, like fufu, pounded yam, unripe plantain paste or flour, combination of millet and guinea corn flour, as it is not easy to identify the garri that is properly processed."