Mulunda Mwanza

Evaluation of analytical assays efficiency to detect aflatoxin M1 in milk from selected areas in Egypt and South Africa

Recently, methods to analyze aflatoxin M1 (AFM1) in milk and dairy products have been developed for both screening purposes (i.e., rapid, economical, and simple methods) and for confirmation by accurate, reproducible, and sensitive quantification. The aim of this study was to evaluate the efficiency of different rapid kits and techniques available on the market by using different analytical methods: thin layer chromatography (TLC), immunoaffinity column, AFM1 immunochromatographic strip, and ELISA; some samples were also submitted to HPLC for comparison of results. One hundred thirty-eight samples were collected from rural subsistence and commercial dairy farms in selected areas of Egypt and South Africa and analyzed for the presence of AFM1. The results obtained by AFM1 immunochromatographic strip indicated the lowest frequency of occurrence, with a detection incidence of 20.45% in Egyptian samples and 16% in South African samples. Aflatoxin M1 was detected by ELISA in 65 (73.9%) Egyptian milk samples, with a range of 8.52 to 78.06 ng/L, and in 34 (68%) South African milk samples, with a range of 5 to 120 ng/L. A higher incidence of AFM1 in Egyptian milk samples was shown by TLC (81.8%) compared with ELISA (73.9%). Samples analyzed by ELISA in South African milk samples demonstrated satisfactory correlation when compared with HPLC coupled with Coring cell (an electrochemical cell for the derivatization of AFM1). Among the positive samples, 18 of the Egyptian samples (20.45%) positive by ELISA had levels of AFM1 above the European Union (EU) regulatory limit (50 ng/L), whereas 65 samples (73.9%) were above the Egyptian regulatory limit (0 ng/L). Six of the South African samples (12%) tested by ELISA were above the South African (50 ng/L) and EU regulatory limits. The mean concentration of AFM1 was 25.79 ng/L in Egyptian samples and 17.06 ng/L by ELISA and 39 ng/L by HPLC in South African samples. These contamination levels would not represent a serious public health hazard according to EU legislation.

Current Status of Mycotoxin Contamination of Food Commodities in Zimbabwe

Agricultural products, especially cereal grains, serve as staple foods in sub-Saharan Africa. However, climatic conditions in this region can lead to contamination of these commodities by moulds, with subsequent production of mycotoxins posing health risks to both humans and animals. There is limited documentation on the occurrence of mycotoxins in sub-Saharan African countries, leading to the exposure of their populations to a wide variety of mycotoxins through consumption of contaminated foods. This review aims at highlighting the current status of mycotoxin contamination of food products in Zimbabwe and recommended strategies of reducing this problem. Zimbabwe is one of the African countries with very little information with regards to mycotoxin contamination of its food commodities, both on the market and at household levels. Even though evidence of multitoxin occurrence in some food commodities such as maize and other staple foods exist, available published research focuses only on Aspergillus and Fusarium mycotoxins, namely aflatoxins, deoxynivalenol (DON), trichothecenes, fumonisins, and zearalenone (ZEA). Occurrence of mycotoxins in the food chain has been mainly associated with poor agricultural practices. Analysis of mycotoxins has been done mainly using chromatographic and immunological methods. Zimbabwe has adopted European standards, but the legislation is quite flexible, with testing for mycotoxin contamination in food commodities being done voluntarily or upon request. Therefore, the country needs to tighten its legislation as well as adopt stricter standards that will improve the food safety and security of the masses.

Microbiological Quality and Risk Assessment for Aflatoxins in Groundnuts and Roasted Cashew Nuts Meant for Human Consumption

Nuts are one of the commonly consumed snacks but poor handling and storage practices can make them prone to foodborne infections. The study aimed at assessing the microbiological quality and risk assessment for aflatoxins in groundnuts and cashew nuts consumed in selected locations in Nigeria. The moisture content, colony counts, incidence of pathogenic bacteria, aflatoxin contamination, and risk assessment for aflatoxins were evaluated using standard methods. The moisture content and total viable count ranged from 5.00–8.60% and 5.5–89 × 103u2009cfug−1, respectively, while the fungal count was between 4–24 × 103 and 1.0–4.5 × 102u2009cfug−1, respectively. Eleven fungal species belonging to 5 genera were isolated from the nuts, with Aspergillus flavus, Rhizopus oryzae, and Fusarium oxysporum having the highest percentage occurrence of 50%. In addition, the aflatoxin concentration ranged 0.1–6.8 and 29–33.78u2009ngu2009kg−1 for cashew nuts and groundnuts, respectively. The margin of exposure (MOE) to aflatoxin contamination was 6.10 for groundnuts and 1000 for cashew nuts and the nuts consumers were at a risk of exposure to foodborne diseases and aflatoxin contamination with mean exposure values of 27.96 and 0.17u2009ngu2009kg−1bwday−1, respectively. The risk of primary liver cancer for groundnuts and cashew nuts consumers was also estimated to be 1.38 and 0.01 canceryear−1100,000−1person, respectively. This calls for mitigation measures from appropriate governmental organizations.

Formulation, sensory evaluation, proximate composition and storage stability of cassava strips produced from the composite flour of cassava and cowpea

Abstract The study developed an acceptable formula for the production of cassava strips (a deep fried product) using composite flour of cassava/cowpea at four different levels of cowpea substitutions (100:0, 90:10, 80:20, and 70:30). Sensory properties, proximate composition, and shelf life at ambient temperature were determined. Proximate composition, shelf life, and microbial analysis were further done on the most preferred sample (80:20) and the control (100:0). Results showed a significant difference between the tested sample and the control, except in their moisture (4.1%–4.2%) and fiber (5.0%) contents which were similar. Protein content increased from 0.9% to 2.6%, fat 24.6% to 28.5%, carbohydrate 59.7% to 61.1%, and ash 1.8% to 2.5% in both control and most preferred sample. Results showed no changes in their peroxide value (2.4 mEq/kg), moisture content (4.1%), and bacterial count of 0 × 102 CFU/g at ambient storage temperature for 4 weeks. The addition of cowpea flour increased the nutritional quality of the cassava strips.

Occurrence of filamentous fungi in maize destined for human consumption in South Africa

Abstract One‐hundred maize samples were analyzed for fungal contamination using conventional and molecular methods. The percentage incidence of different genera isolated revealed the predominance of Fusarium (82%), Penicillium (63%), and Aspergillus species (33%) compared to other genera. Fusarium occurred in 90% and 74% of small scale and commercial samples, respectively, while Penicillium occurred in small scale and commercial samples at an incidence rate of 64% and 62%, respectively. However, among the species, Fusarium verticilloides have the highest incidence of 70% and 76% in commercial and small‐scale maize, respectively, while Penicillium digitatum has 56% total incidence. Aspergillus fumigatus (27%) were also the most dominant of these genera. Fungal genera isolated included Alternaria and Cladosporium although occurring at a lower incidence level of 30%, 32% and 16%, 20%, respectively, in small‐scale and commercial samples. The results emphasize that farmers and consumers should be alerted to the danger of fungal contamination in maize.

Evaluation of Antibiotic Residues in Raw Meat Using Different Analytical Methods

Antibiotic residue in meat is a serious public health concern due to its harmful effects on consumer health. This study aimed at estimating the residue levels of four commonly used antibiotics in meat samples using three analytical methods (ELISA, TLC and HPLC). A total of 150 samples of raw meat from sales points were analysed for ciprofloxacin, streptomycin, tetracycline, and sulphanilamide residues. Overall, ELISA analysis showed that 56, 34, 18, and 25.3% of the samples tested positive for ciprofloxacin, streptomycin, sulphanilamide and tetracycline residues respectively while TLC and HPLC detected 21.4, 29.4, 92.5, and 14.6%, and 8.3, 41.1, 88.8, and 14.6% of the samples as containing the residues, with ciprofloxacin and sulphanilamide having the lowest and highest occurrence, respectively. Furthermore, the concentrations of antibiotic residues were in the ranges of 19.8–92.8, 26.6–489.1, 14.2–1280.8, and 42.6–355.6 μg/kg with ELISA, while HPLC detected concentration ranges of 20.7–82.1, 41.8–320.8, 65.2–952.2 and 32.8–95.6 μg/kg for sulphanilamide, tetracycline, streptomycin, and ciprofloxacin, respectively. Mean ciprofloxacin and streptomycin residue levels were above the Codex/SA MRL recommended limit, while 3% of the samples contained multidrug residues. Although some of the mean residues levels were below the permissible limits, the co-occurrence of multidrug residues in some of the samples calls for concern.

Factors Influencing Goat’s Semen Fertility and Storage: A Literature Review

Abstract The present review paper gives an idea about the candidate genes for buck fertility, including genes encoding hormones, their receptors, proteins of the seminal plasma, proteins involved in spermatozoa-ovum binding and genes influencing sexual development. Buck reproductive performance is highly influenced by semen quality. The quality of sperm after freezing is very important for success of artificial inseminations. Adopting marker could assist selection of candidate gene for genetic improvement of the bucks’ fertility. Decrease in fertility is a multifactorial condition which is very difficult to diagnose. Among various causes, genetic abnormality holds a major share. By identifying various genes that have effects on fertility, the genetic cause behind sub-fertility can be explored and also other non-genetic factors can be identified. Molecular genetic tools enables to explore individual genes in animals. Identification of these genes will eventually lead to genome assembly and development of novel tools for analyzing complex genetic traits.

Prevalence and Antibiotic Resistance of Staphylococcus aureus Isolated from Beef Carcasses at Abattoirs in North West Province

Abstract Staphylococcus aureus is notorious for causing human diseases, and is primarily associated with the consumption of contaminated meat and meat products. The aim of this paper was to determine the prevalence and the antibiotic resistant profiles of Staphylococcus aureus on beef carcasses isolated from different abattoirs in North West Province. A total of 600 swab samples were collected from beef carcasses, and cultured on Mannitol salt agar (MSA). The isolates were confirmed by morphological identification and biochemical tests. A total of 159 (26.5%) samples were contaminated with S. aureus. All the S. aureus isolates showed high susceptibility to Chloramphenicol (30uf0ecg), Gentamicin (10uf0ecg) and Tetracycline (10uf0ecg). However, all isolates were highly resistant to Penicillin (10uf0ecg), Ampicillin (30 uf0ecg) and Oxytetracycline (10uf0ecg). The study confirms the presence of S. aureus in beef carcasses, which might be a potential threat to the consumer’s health.

Determination of Factors That Influence Reproductive Conditions in Cows in the Rural Farms of the Ngaka Modiri Molema District of the North West Province

Abstract Reproductive disorders in communal farming remain answerable to economic losses and poor reproductive performance. The aim of this study was to identify factors that influence the prevalence of reproductive conditions in cattle in the semi-arid area of Ngaka Modiri Molema district, North West Province. This study focused on five reproductive conditions, that is, downer cow syndrome, dystocia, abortion, retained placenta and vaginal prolapses. Questionnaires were used to collect data from 65 farmers during farm visits and at community outreaches. Results obtained from the survey showed that among 65 cases of reproductive conditions encountered in this study, dystocia (26.2%), retained placentas (23.1%), abortion (23.1%), downer cow syndrome (20%) and vaginal prolapses (7.7%). The results also indicate the following probabilities including body condition score (P=0.37), breed type (P=0.025), parity (P=0.54), treatment given to the cow (P=0.68), cows supplemented (P=0.21) and medical history (P=0.58). The condition most encountered in this study was dystocia and the difference in the breed type showed to be very influential in the prevalence of these conditions. There is a need to implement sustainable strategies to improve production and educate the farmer on methods that can reduce the incidences of reproductive conditions.

Prevalent Bovine Internal Parasites Using Different Techniques in Communal Farms around Mafikeng

Abstract Knowledge of the nematodes species present in a particular geographical location and their biology and epidemiology has important implications for the control of gastrointestinal parasites. The main objective of the study is to compare Zinc Sulphate, Sheather’s solution, and sodium nitrate and concentrated salt solution flotation techniques in the identification of bovine internal parasites around the Mafikeng area. Simple random study of analysis of bovine fecal samples collected from Mafikeng area during the dry season was used, using egg per gram centrifugal flotation techniques of feces collected the same day. Direct smears using both iodine and saline were also performed to detect motile parasites stages. Of the two direct methods of detecting motile parasitic stages, iodine was more sensitive with only twenty percent negative results compared to forty percent using saline. Also, highest egg burden of 11-15 was found in ten percent of iodine samples compared to seven percent of saline samples. Comparison of flotation techniques showed that sodium nitrite had a negative score of twenty-two percent followed by zinc sulphate, Sheather’s, and concentrated salt at fifteen percent, twelve percent and six percent, respectively. Highest egg burden of 1100-1599 was found in ten percent of samples using sodium nitrate compared to eight percent, five percent and three percent for Sheather’s, zinc sulphate and saturated salt solution, respectively. From the results, the researchers can conclude that saturated salt solution and Sheather’s solution are methods of choice for identifying bovine intestinal parasites, and they should be used in conjunction with direct methods using iodine especially for semi-solid to loose feces. For routine diagnostic work, the researchers recommend sodium nitrite although it had a higher negative value because it is cheap, easier to use and less messy than the other techniques. Also, it is the second best in detecting moderate to heavy infection with parasites only superseded by concentrated salt solution.