An Optical Test Strip for the Detection of Benzoic Acid in Food

Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (Ki) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products

The good the bad & ugly of food safety: from molecules to mirobes

Food safety is about ensuring that our food is safe to eat. Food quality concerns ensuring that it is nutritious and acceptable. Food safety is the absolute priority. It must be assured to protect the consumer, and to maintain and expand food markets. Like all disease, foodborne illness seems to strike at random. When people are exposed to foodborne microbes, some of them get sick while many others will suffer few or no ill effects. Foodborne diseases are largely preventable, though there is no simple one-step prevention measure like a vaccine. Instead, measures are needed to prevent or limit contamination all the way from the farm to the table. • A variety of good agricultural and manufacturing practices can reduce the spread of microbes among animals and prevent the contamination of foods. • Careful review of the whole food production process can identify the principal hazards, and the control points where contamination can be prevented, limited, or eliminated. • A formal method for evaluating the control of risk in foods exists is called the Hazard Analysis Critical Control Point, or HACCP system. This was first developed by NASA to make sure that the food eaten by astronauts was safe. HACCP safety principles are now being applied to an increasing spectrum of foods, including meat, poultry, and seafood. For some particularly risky foods, even the most careful hygiene and sanitation are insufficient to prevent contamination, and a definitive microbe-killing step must be included in the process. The main concern is the safety hazards associated with the poultry and aquaculture food animals especially bacterial pathogens. Currently, the most fail-safe method is to consistently monitor the bacterial level in the food animals from the point immediately after obtaining them to just before it is sold to the consumer. However, this has done very little to reduce food poisoning among consumers, as it is time-consuming and lacks reinforcement in some improvised areas of the world. Therefore, research is ongoing worldwide on finding a way to reduce, if not, remove the hazards present in the food animals, either by prevention (before or during its growth), or production. This publication discusses the importance of food safety. It analyzes issues related to food safety, such as spoilage, food-borne pathogens and the microbiological quality of food including some of the examples of work carried out by our research group. It then discusses the significance of contaminants such as biogenic amines with regards to food safety during handling and storage. Our findings provide significant information regarding histamine degrading bacteria and factors influencing its activity. In addition, the findings also emphasized the effectiveness of using bacteria with amines oxidase activity in reducing histamine accumulation in fermented food products. Lastly, the publication looks at the development of rapid enzyme-based biosensor technology in detecting histamine and formaldehyde in fish and seafoods

The detection of glyphosate and glyphosate-based herbicides in water, using nanotechnology

Glyphosate (N-phosphonomethylglycine) is an organophosphate compound which was developed by the Monsanto Company in 1971 and is the active ingredient found in several herbicide formulations. The use of glyphosate-based herbicides in South Africa for the control of alien invasive plants and weeds is well established, extensive and currently unregulated, which vastly increases the likelihood of glyphosate contamination in environmental water systems. Although the use of glyphosate-based herbicides is required for economic enhancement in industries such as agriculture, the presence of this compound in natural water systems presents a potential risk to human health. Glyphosate and glyphosate formulations were previously considered safe, however their toxicity has become a major focal point of research over recent years. The lack of monitoring protocols for pesticides in South Africa is primarily due to limited financial capacity and the lack of analytical techniques