Controlling bacteria during oil extraction from nuts
The Palabora Foundation, the social arm of the Palabora Mining Company, has addressed concerns raised in recent years about the potential for bacteria from marula nuts being transferred to oil extracted during the cracking process. Using a novel solution, based on its experience at the local Maphutha Malatji Hospital, the Foundation is using antimicrobial copper to assist in this procedure.
In 2011, the Foundation established five cooperatives in rural Phalaborwa in the Limpopo Province of South Africa. These cooperatives were tasked with collecting the abundant marula fruit crop for making traditional beer, and the marula nuts from which valuable oil is extracted. The oil extracted from the marula nuts is used to supply the cosmetics industry.
During the summer months, the fruit of the marula tree is used to produce a traditional beer, but during the rest of the year the cooperative members crack the marula nuts to expose the kernel, which is then pressed to produce the precious oil. This is traditionally done by holding the nut on a rock and hitting it with a stone to remove the hard outer shell of the nut and reveal the kernel. This method is labour intensive and causes a large number of hand injuries every year.
Copper – an inherently antimicrobial material capable of rapidly and completely killing harmful pathogens on contact – is already being used in healthcare facilities around the world in the form of touch surfaces such as taps, door handles, counters and trolleys. At the Maphutha Malatji Hospital in Phalaborwa, antimicrobial copper door handles, push plates, shelves, basins and taps were installed in 2011 as an additional infection control measure to help reduce the risk of healthcare-associated infections.
Copper shares its antimicrobial efficacy with many commonly-used alloys including brasses and bronzes, and these offer hard-wearing surfaces in a range of colours that continuously reduce surface contamination. Brass is made when copper is combined with zinc, and has comparable yield strengths to low alloy steels, some stainless steels and some aluminium alloys.
The five cooperatives have begun to use brass topped tables during the cracking stage, where machines remove the hard outer shell of the nut to expose the kernel. This has already resulted in an increase in production and a decrease in debilitating hand injuries.
Marula oil has tremendous anti-aging, skin hydration and medical benefits that make it very valuable to the cosmetics industry. Given the antimicrobial properties of this copper alloy, these brass topped surfaces will reduce the transfer of bacteria, ensuring that the oil is free from undesirable elements.