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Occurrence of antibiotic residues in milk: a case study of Gweru 2014.

Nyoka, Ruth — Wed, 01 Jan 2014 00:00:00 GMT

Title: Occurrence of antibiotic residues in milk: a case study of Gweru 2014. Authors: Nyoka, Ruth Abstract: The aim of the research was to determine the occurrence of antibiotic residues in milk in Gweru. The population consisted of twenty-eight farmers. Ten farmers were randomly selected from the population. The average volume that the farmers supply to dairy processing companies was twenty thousand liters during the time of sampling. Raw milk was sampled in two hundred and fifty mls sterile sample bottles. The samples were frozen up to the time of analysis. Detection and quantitation of antibiotic residues was done using High Performance Liquid Chromatography coupled to a mass spectroscopy detector (HPLC-MS). Fourteen antibiotics were analyzed for and these are: the sulphonamides,(trimethoprin, sulfaquinoxali, sulfamethoxin, sulfamethoxazole, sulfamethizole, sulfamethazine and sulfachloropyril), the steroids dexamethasone, the flouroquinolones which is enrofloxacin , the β-Lactams which is Penicillin G and amoxicillin as well as the Benzimidazoles which are thiabendazole and albendazole. Only one antibiotic which is albendazole was detectable on the two analyses which were done separately on the qualitative HPLC-MS machine in all the samples. The quantities of the albendazole were then quantified on the Quantitative HPLC-MS machine. During the first analysis farmer A had 241.31ppb albendazole and this was above 100ppb which is the Codex maximum residual limit for albendazole. On the second analysis done farmers ,A, B, C, D, E, F had 239.8ppb, 118.34ppb, 140.63ppb, 254.13ppb, 252.57ppb and 198.62ppb respectively which were above the 100ppb Codex Standard and other farmers were below 100ppb. T-test at 95% significance level showed that there is no significant difference in antibiotic concentration among Dairy farmers that supply milk to Dairy processing companies around Gweru. The effect of albendazole on fermentation of milk was done using back fermentation with 40ml of fermented milk in 500ml of fresh milk. Albendazole was added at different concentrations which were 0, 100, 500, 750, 1000 and 2000μL. pH was measured using a pH meter and lactic acid content was determined by using freshly prepared 0.1N sodium hydroxide. Albendazole slows down the rate of fermentation as pH and percentage lactic acid content was less in the sample with 2000μl albendazole added. pH change was highest in the samples with no antibiotic added. One way ANOVA done at 99% significance level showed that the lactic acid content vary significantly with antibiotic concentration. Regression analysis showed that there is a strong positive correlation (R2= 0.967) between antibiotic concentration and percentage lactic acid.

A comparison of the changes in seed germination vigour with prolonged storage time between Hope and Sierra malting barley varieties at Delta Beverages, Kwekwe Maltings.

Mwazha, Milford — Wed, 01 Jan 2014 00:00:00 GMT

Title: A comparison of the changes in seed germination vigour with prolonged storage time between Hope and Sierra malting barley varieties at Delta Beverages, Kwekwe Maltings. Authors: Mwazha, Milford Abstract: To increase the brewing yield and efficiency, malts with high extract values, high enzymatic activities, and good modification are essential. To produce malt that meets these requirements, the barley employed must have minimal post-harvest dormancy and be able to germinate rapidly and uniformly. The aims of this study were to compare the changes in seed germination vigour trends and the general storage stability of two Zimbabwean two-row malting barley varieties (Hope and Sierra) as the post-harvest storage time increased. Two samples of these commercially grown varieties were obtained and stored under room temperature laboratory conditions. At monthly intervals the samples had their germination index and energy determined using SAB Miller standards for malting barley analysis (controlled germination in an incubator at 18oC – 21oC for 72 hours). In addition other quality parameters (nitrogen content, screenings, moisture content, water sensitivity and insect damage index) necessary to assess the storage stability of both varieties were also analyzed on monthly intervals using the same analytical standards as for germination tests. On the basis of the results obtained during the 13 months of post-harvest assessments it was found out that Hope had its Germination Index improving as storage time increased meaning that , the variety’s germination vigour improves with time. By the first month of the research the GI index for Hope was 8.7 and gradually it increased reaching 9.2 by the end of the research period. However on the other hand the seed germination vigour for Sierra gradually diminishes with time as indicated by the weak negative downhill correlation (r value = -0.24). As for other grain quality parameters (including moisture loss, insect damage index, germination energy and screenings) Hope proved to be more stable in storage than Sierra. Thus after considering germination performance and general storage stability it was concluded that Hope is a better malting barley variety than Sierra.

Effects of enzyme maceration on physicochemical properties and micronutrient bioaccessibility of Strychnos cocculoides products (juice/porridge)

Nyoni, Qhubekani — Sun, 01 Jan 2017 00:00:00 GMT

Title: Effects of enzyme maceration on physicochemical properties and micronutrient bioaccessibility of Strychnos cocculoides products (juice/porridge) Authors: Nyoni, Qhubekani Abstract: Information on the nutritional content and health-promoting properties of African indigenous fruits is very limited. Although the limited available literature does point towards wealth in essential nutrients, micronutrients and antioxidants there is still a need to fill the gap to ascertain health and nutritional claims that have been passed on from previous generations. Studies on the impact of processing of the fruit pulp on physicochemical, nutritional properties, and digestibility thereof are still very scarce and fragmented. Hence, the focus of this study was to explore enzyme (pectinase) maceration as a processing option to enhance physicochemical properties, antioxidant activity, antimicrobial potential and bioaccessibility of selected micronutrients in Strychnos cocculoides (S, cocculoides) juice/pulp. In this context, enzyme maceration refers to the breakdown of pectin that occurs in fruit pulp as complex structural polysaccharides into simpler, soluble compounds by the action of a commercial mixture of pectinases. Enzyme maceration has been reported to be beneficial in improving juice yield and enhances release of bioactive compounds into resultant juice from fruit pulps. Since the juice is commonly consumed with maize-meal porridge, the S. cocculoides enriched porridge was also incorporated into the study. Physicochemical properties were assayed using standard methods, mineral analysis by ICP-OES, phenolic compound assay by the Folin Ciocalteau method, antioxidant activity by DPPH radical scavenging ability, antimicrobial activity by the disc diffusion method and bioaccessibility was assayed using the Infogest digestion protocol. Sensory evaluation was also done to gauge the acceptance of the enzyme macerated samples. The physicochemical properties of the enzyme macerated juice and enzyme porridge were more appreciable compared to their nonenzyme counterparts. The mineral content was highest in the pulp (9.12 mg/100g for iron and 2.04 mg/100g for zinc) followed by enzyme macerated juice (8.89 mg/100g for iron and 2 mg/100g for zinc). The enzyme porridge also recorded higher levels of mineral content. Vitamin C content was affected by the thermal processing used in juice extraction and porridge preparation, although the enzyme juice still contained appreciable vitamin C content (9.45 mg/100g). The total phenol content was also higher in the enzyme juice with recorded value of 3327.75 mg/100g. The same trend was observed for antioxidant and antimicrobial activities with the enzyme macerated juice recording higher results (76.4 % for DPPH radical scavenging AOA). The bioaccessibility of iron, zinc, ascorbic acid and total phenolic compounds was higher in the enzyme treated samples, with values of 28.76 %, 18.14 %, 37.89 % and 36.75 % respectively in enzyme macerated juice. The bioaccessibility of micronutrients was significantly lower (p < 0.05) in the porridge samples, clearly highlighting the effect of the food matrix in determining bioaccessibility. The enzyme macerated samples had higher acceptance on sensory evaluation. The observed results in this study are mostly attributable to the breakdown of the complex polysaccharide, pectin, into simpler more volatile compounds such as galacturonic acid. From the observed results it can be concluded that enzyme macerated S. cocculoides juice is an excellent source of some bioaccessible micronutrients and phenolic compounds; hence its consumption should be encouraged especially in nutrition-related intervention programmes. However further research is still needed to identify individual specific phenolic compounds in S. cocculoides juice and how they are affected by enzyme maceration and in-vitro digestion. The work done in this study can also be employed for other indigenous fruits to promote their utilisation and increase their value.

Antimicrobial properties of tamarindus indica linn leaf extracts

Ngulube, Leratiloe M. — Sun, 01 Jan 2017 00:00:00 GMT

Title: Antimicrobial properties of tamarindus indica linn leaf extracts Authors: Ngulube, Leratiloe M. Abstract: Tamarindus indica l leaves extract was evaluated against six bacterial strains (2 Gram-positive and 4 Gram-negative) known to cause food spoilage. Functional groups of Tamarindus indica l leaves were evaluated using the Fourier transform infrared (FTIR) spectroscopy. The leaves were extracted by the Soxhlet extraction using aqueous and organic solvents (acetone, ethanol and methanol). Stock solution of the extracts was prepared by dissolving 0.8g of each extract in 2ml dimethyl sulphoxide (DMSO) to obtain a concentration of 400mg/ml and the concentration of 200mg/ml was prepared by serial doubling dilution of stock solution and 2ml of DMSO was added. Inoculum suspension was prepared by suspending appropriate colonies of the test microorganisms in sterile distilled water. The 0.5 McFarland of 1% barium chloride and 1% sulphuric acid was used to standardize the inoculum. The antimicrobial activity of the concentrated extracts was evaluated by determination of the zones of inhibition against the test microorganisms using the disc diffusion method. The results of the FTIR revealed the presence of primary and secondary amines and amides, carboxylic acid, alkenes and alkanes, fluorides, amines and aromatics. The extracts were active against both gram-positive and gram-negative bacteria. The activity of the plant extracts could have been affected by different temperature ranges, nature of the tree of freshness and dryness of the leaves. All extracts showed appreciable inhibition on the test microorganisms with the zones of inhibition ranging from 6.4 mm-19.8mm and ethanol extracts showed a broader spectrum of activity against the test microorganisms. Results obtained of this study indicate that Tamarindus indica l has broad spectrum antibacterial activity and a potential source of new classes of natural preservatives that could be useful for replacement of synthetic food grade preservatives