Thesis (MScFoodSc)--Stellenbosch University, 2019. | ENGLISH ABSTRACT: Irrigation water has been identified as one way by which fresh produce can become contaminated with pathogens. This is a concern in South Africa, where some rivers used for the irrigation of fresh produce often carry pathogens. In this regard, treating river water prior to irrigation is important to reduce the possible risk of foodborne disease outbreaks associated with the consumption of contaminated produce. Ultraviolet (UV) irradiation can be used to decontaminate water and has been shown to be effective against waterborne pathogens. Knowledge gaps, however, still exist regarding the minimum effective UV dose required to effectively inactivate different waterborne pathogens. The aim of this study was, therefore, to evaluate the disinfection efficacy of low-pressure (LP) UV on river water. Escherichia coli (E. coli) strains including three Shiga-toxin producing Escherichia coli (STEC) strains were exposed to five different UV doses (20, 30, 40, 50 and 60 mJ.cm-2) in sterile Ringer’s solution. Variation in UV sensitivity among strains was observed at all doses. Log reductions ranged between 3.6 - 4.4 log for the lowest dose (20 mJ.cm -2). Environmental strains were more UV resistant than the ATCC strain. Based on these results, the influence of water quality on UV irradiation efficacy was investigated by inoculating a resistant environmental STEC strain (STEC 210) into both autoclaved river water and Ringer’s solution. Results showed that water quality parameters did not negatively influence UV disinfection efficacy provided the same dose was applied. The disinfection efficacy of UV (40 and 60 mJ.cm-2) irradiation was then investigated against river water (Eerste, Krom and Plankenburg rivers). The Eerste River showed E. coli levels falling below the recommended irrigation guideline limit. The Krom River also showed low E. coli levels, but a once-off STEC detection, as well as the consistent occurrence of ESBL producing Enterobacteriaceae was observed. The Plankenburg River showed the highest E. coli levels and consistent detection of STEC and ESBL producing Enterobacteriaceae. UV irradiation of the Eerste and Krom rivers resulted in undetectable levels of Enterobacteriaceae, total coliforms and E. coli. A targeted three log reduction was achieved following disinfection of the Plankenburg River water at both UV doses. This resulted in water within acceptable irrigation standards. A dose of 40 mJ.cm-2 was, however, ineffective against STEC. Repair of all indicator populations was observed and was less than 1% at both UV doses (40 and 60 mJ.cm-2) but, was less at the higher dose (60 mJ.cm-2). Lastly, the effects of combining pine biochar filtration with UV irradiation was investigated on river water. The combination treatment resulted in improved UVT% and better UV irradiation efficacy of microorganisms. Overall, UV irradiation showed potential in producing water of acceptable standard for fresh produce irrigation in terms of the E. coli load. However, UV efficacy against other important waterborne pathogens such as Salmonella was not investigated. It is recommended that, the disinfection efficacy of UV against these pathogens, be investigated in future. Acceptable levels of these pathogens in irrigation water should also be explored, to make guideline recommendations. | AFRIKAANSE OPSOMMING: Besproeiingswater is geïdentifiseer as een manier waarop vars landbouprodukte met patogene besmet kan word. Dit is van belang in Suid-Afrika waar sommige riviere wat vir besproeiing van vars produkte aangewend word dikwels patogene bevat. In hierdie verband is dit belangrik om rivierwater voor besproeiing te behandel om sodoende die moontlike risiko van voedseloordraagbare siektes wat met die inname van besmette produkte geassosieer word, te verminder. Ultraviolet (UV) bestraling kan gebruik word om water te ontsmet en daar is gevind dat dit effektief is teen watergedraagde patogene. Kennisgapings bestaan egter steeds ten opsigte van die minimum effektiewe UV dosis wat benodig word om verskillende watergedraagde patogene effektief te inaktiveer. Die doel van hierdie studie was dus om die ontsmettingseffektiwiteit van lae druk (LP) UV bestraling op rivierwater te evalueer. Escherichia coli (E. coli) isolate, insluitend drie Shiga-toksien produserende Escherichia coli (STEC) isolate, is blootgestel aan vyf verskillende UV dosisse (20, 30, 40, 50 en 60 mJ.cm-2) in steriele Ringer’s oplossing. Variasie in UV sensitiwiteit is tussen isolate waargeneem teen alle dosisse. Log reduksies het gewissel tussen 3.6 - 4.4 log vir die laagste dosis (20 mJ.cm -2). Omgewingsisolate was meer UV bestand as die ATCC isolaat. Gebaseer op hierdie resultate is die invloed van waterkwaliteit op UV bestralingseffektiwiteit ondersoek deur ‘n UV weerstandbiedende omgewing-STEC isolaat (STEC 210) in beide geoutoklafeerde rivierwater en Ringer’s oplossing te inokuleer. Die resultate het gewys dat waterkwaliteit parameters nie UV ontsmettingseffektiwiteit negatief beïnvloed nie mits die regte dosis toegepas is. Die ontsmettingseffektiwiteit van UV (40 en 60 mJ.cm-2) bestraling is daarna ondersoek in rivierwater (Eerste, Krom en Plankenburg riviere). Die Eerste rivier het E. coli vlakke getoon wat voldoen aan die aanbevole besproeiingsriglyn limiete . Die Krom rivier het ook lae E. coli vlakke getoon, maar ‘n eenmalige STEC teenwoordigheid, sowel as die konsekwente teenwoordigheid van ESBL produserende Enterobacteriaceae is waargeneem. Die Plankenburg rivier het die hoogste E. coli vlakke getoon asookkonsekwente teenwoordigheid van STEC en ESBL produserende Enterobacteriaceae. UV bestraling van die Eerste en Krom Riviere het gelei tot onopspoorbare lae vlakke van Enterobacteriaceae, totale kolivorme en E. coli. ‘n Geteikende drie log reduksie is behaal na behandeling van die Plankenburg Rivier water met beide UV dosisse. Dit het daartoe gelei dat die water binne aanvaarbare besproeiing standaarde val. ‘n Dosis van 40 mJ.cm-2 was egter oneffektief teen STEC. Die herstel van alle indikatorpopulasies is waargeneem en was minder as 1% by beide UV dosisse (40 en 60 mJ.cm-2), maar was minder by die hoër dosis (60 mJ.cm-2). Laastens is die effek van ‘n kombinasie van denneboom “biochar” filtrasie met UV bestraling op rivierwater ondersoek. Die kombinasie-behandeling het gelei tot ‘n verbeterde UVT% en beter UV bestralingseffektiwiteit teen mikroörganismes. In geheel toon UV bestraling die potensiaal om water van ‘n aanvaarbare standaard vir vars produk besproeiing, in terme van die E. coli lading, te produseer. UV bestralingseffektiwiteit teenoor ander belangrike watergedraagde voedselpatogene, soos Salmonella, is nie ondersoek nie. Daar word aanbeveel dat die ontsmettingseffektiwiteit van UV teenoor hierdie patogene in die toekoms ondersoek word. Aanvaarbare vlakke van hierdie patogene in besproeiingswater moet ook bepaal word om sodoende riglyn-aanbevelings te maak.

The mechanism of action, safety, and efficacy of IUDs were reviewed by a WHO Scientific Group in 1986. The Scientific Group concluded that the IUD should continue to be supported, in both developed and developing countries, as a safe, reliable method of fertility regulation. The newer copper-releasing devices are comparable to oral contraceptives in terms of safety and efficacy. When compared to women who use other reversible methods of contraception, IUD users have the lowest mortality resulting from deaths directly attributable to those methods or to the consequences of unwanted pregnancy. In the past decade, research has concentrated on the development of new devices that have both higher continuation rates and lower rates of expulsion and removal for bleeding abnormalities. An important recent concern has been the possible increased risk of pelvic inflammatory disease (PID) and subsequent tubal infertility associated with IUD use. However, it now appears that methodological problems have caused the IUD-associated risk of PID to be overestimated. The increased risk with IUDs seems to be limited to the 1st 4 months of use. No increased risk of tubal infertility has been found among IUD users in stable, monogamous sexual relationships. The use of a copper IUD after the 1st pregnancy is not associated with secondary infertility due to tubal disease. Finally, the newer copper IUDs have low rates of ectopic pregnancy.

Introduction and objective Conditions of a healthy, friendly and safe work environment and proper work organisation increase self-efficacy and decrease or eliminate the factors causing the occurrence of burnout symptoms, all of which have a decisive impact on increasing the quality of work. The aim of the study was to analyse and assess the influence of factors of work environment and burnout syndrome on the self-efficacy of medical staff. Material and Methods The study comprised randomly selected professionally-active nurses working on hospital wards (N=405) on the area of two provinces in Poland. The study used the Generalized Self-Efficacy Scale, Copenhagen Burnout Inventory and a questionnaire concerning the factors that influence the process of work organisation at nursing positions in hospitals. Results Lower scores for self-efficacy resulted in a worse assessment of development opportunities and promotion prospects (r=-0.11), participation in the decision-making process (r=-0.11) and teamwork (r=-0.10). Lower self-efficacy contributed to the occurrence of burnout symptoms r∈[-0.19 – -0.17]. Conclusions Properly shaped and used organisational factors are stimulating for professional efficiency and effectiveness, and consequently, for the quality of nursing work. Negative assessment of the factors in the work environment contributes to the occurrence of burnout symptoms and decrease in self-efficacy. Nurses with lower self-efficacy more often experienced symptoms of burnout.

Citrus plants often suffer from temperature stress, which seriously inhibits tree growth and even results in tree death. The present experiment was conducted to evaluate the effects of Glomus mosseae on growth, root morphology, superoxide dismutase (SOD) and catalase (CAT) activities, and soluble protein content of trifoliate orange (Poncirus trifoliata) seedlings at low (15°C), optimum (25°C) and high (35°C) temperatures. Sixty-eight days after temperature stresses, mycorrhizal colonization and number of both entry points and vesicles were significantly inhibited by low or high temperature. Mycorrhizal seedlings recorded significantly higher growth characteristics than non-mycorrhizal seedlings at both optimum and high temperatures, but the beneficial effects were almost lost at low temperature. Generally, mycorrhizal seedlings presented notably higher root traits (projected area, surface area, number of forks and volume) than non-mycorrhizal seedlings regardless of temperature levels. Mycorrhizal colonization significantly increased SOD and CAT activities and soluble protein content at high temperature, increased only SOD activity at optimum temperature, and decreased only soluble protein content at low temperature. It suggests that mycorrhizal alleviation of temperature stress in trifoliate orange seedlings was at high temperature, but the alleviation was obviously weakened at low temperature.

Two growth trials and a short-term metabolism trial were conducted in broiler chickens in the period of 22 to 42 days of age in order to evaluate the effects of two dietary levels of L-lactic acid (1.03 or 2.06 g/kg) and microbial 6-phytase (750 U/kg), added either separately or in combination, on growth rate, feed conversion, dressing percentage and utilization of selected nutrients. In the first growth trial, six different dietary treatments were added to a basal grower diet containing 19.4% crude protein and a reduced level of dietary phosphorus (P) (5.9 g total and 2.9 g non-phytate P per kg). Single administration of L-lactic acid did not show any positive effect on the growth rate or feed conversion. In contrast, phytase addition to a low-P grower diet resulted in the increased final weight of birds and higher feed conversion. This beneficial effect was markedly stronger when the microbial phytase was added to the diets containing L-lactic acid. Based on two-factor analysis of variance, microbial phytase significantly increased the mean final weight by 6.5% (P < 0.01) and significantly improved feed conversion from 1.877 to 1.829 (P < 0.05). In the second growth trial, the same six dietary treatments were added to a basal diet containing a standard level of dietary P (6.7 g total and 4.0 g non-phytate P per kg), but the level of crude protein was reduced to 17.0%. L-lactic acid alone did not show any positive effects on performance. Phytase supplementation alone resulted in numerical improvement of the final weight (+1.1-2.4%), but a higher effect was observed in the diets containing L-lactic acid. In agreement with the reduced final weights of broilers fed the low-protein diets, markedly higher values of feed/gain ratio were noted. In the metabolism trial, selected dietary treatments were involved to evaluate the effects of L-lactic acid and microbial phytase, added either separately or in combination, on the digestibility of nitrogen (N) and fat as well as on the retention and excretion of N and P. Apparent digestibility of N and fat in the low-P diets was not affected by dietary treatments. Retention and utilization of N were numerically higher in all treatments fed low-P diets when compared to the treatment fed a standard diet, but the differences were not significant. Retention of P was numerically higher in all treatments fed low-P diets. When compared to the standard diet, the combination of phytase and L-lactic acid increased daily P retention by 37.6%. P excretion was significantly (P < 0.05) reduced in all treatments fed low-P diets supplemented by both test products, either separately or in combination. A numerical decrease in N excretion was noted in both treatments fed low-protein diets.

This study was designed to determine the prevalence of Neospora caninum, the effect of infection on abortion and fertility parameters and the efficacy and outcomes with combination treatment in a dairy farm with high abortion rates and low fertility parameters. Four hundred and eighty-six cows were tested using the immunofluorescence antibody test (IFAT). The seroprevalence of N. caninum was 19%. Sulphadiazine-trimethoprim and toltrazuril were administered to the seropositive animals. The risk of abortion increased 19-fold in animals infected with N. caninum (P < 0.05), and N. caninum-induced abortions occurred more often between the fourth and the sixth months of gestation. N. caninum infection also had an adverse influence on the number of inseminations to conception (P < 0.05) and calving to conception interval (P < 0.05). The treatment protocol improved the fertility parameters. Although, it is not a radical approach, this combination therapy may be recommended as the primary treatment in neosporosis.

Abstract. The effectiveness of a utility model – remote piston injector for veterinary use was investigated. The injector is from the field of applied veterinary technology, hand tools, instruments and accessories for the application of treatment and prevention of domestic and wild animals. It can be used safely for the application of various types of veterinary medicinal products in relation to animal health and welfare. The utility model is part of the technique that serves to improve veterinary care and is a mobile tool related to the prevention, diagnosis and treatment of animal diseases. It has been found that it successfully provides treatment to dangerous animals with drugs, vaccines, etc. from a distance safely for humans, using cheap disposable or remote syringes that are protected by the injector housing.

Abstract. The research was conducted during 2019 – 2022 on pellic vertisol soil type. Under investigation was lentil cultivar Ilina (Lens culinaris Medik.). A total of 23 variants were investigated: untreated control, 8 herbicides – Pendistar 40 SC (pendimethalin), Dual gold 960 EC (S-metolachlor), Lentagran VP (pyridate), Challenge 600 SC (aclonifen), Zencor 600 SC (metribuzin), Wish top (quizalofop-P-ethyl), Zetrola (propaquizafop) and Passat 40 (imazamox), as well as combinations and tank mixtures between them. Soil-applied herbicides were used during the period after sowing before emergence. Foliar-applied herbicides were used during 2-3, 4-5 or 6-7 real leaf stage of the lentil. All of the herbicides, herbicide combinations and herbicide tank-mixtures were applied in a working solution of 300 l/ha. Mixing of foliar-applied herbicides was done in the tank on the sprayer. The combinations of herbicide Lentagran with soil-applied herbicides Pendistar and Dual gold, as well as herbicides Challenge with foliar-applied herbicides Wish top and Zetrola had an additive effect on herbicide efficacy. The herbicides Lentagran and Zencor, as well as their combinations, successfully controlled Clearfield and ExpressSun sunflower self-sown plants in lentil crops. The foliar-applied herbicide Passat controlled all annual and perennial broadleaved and graminaceous weeds and self-sown plants. The use of foliar-applied herbicide Passat and soil-applied herbicide Zencor at a dose of 900 g/ha led to high phytotoxicity in lentil plants – rate 3 according to the scale of EWRS. Double use of Zencor at doses of 600 + 300 g/ha and the combined use of the herbicides Challenge and Zetrola led to low phytotoxicity in lentil – rate 2 according to the scale of EWRS. The highest yields of lentil seeds were obtained by use of herbicide combinations Pendistar 5 l/ha + Lentagran 500 + 500 ml/ha and Pendistar 5 l/ha + Lentagran 1 l/ha. High yields were also obtained when combining Challenge 3 + 1 l/ha with Wish top 1.25 l/ha, as well as by the herbicide combination Challenge 4 l/ha + Wish top 1.25 l/ha.

A laboratory experiment of a completely randomised design and replicated four times evaluated the effectiveness to control the bruchid, Callosobruchus maculatus in cowpea by the synthetic insecticide Actellic dust, and by the natural protectants ash, coconut oil, powdered cloves and black pepper. The data collected included the number of damaged and undamaged seeds, weight of damaged and undamaged seeds and the number of live and dead bruchids. Seeds treated with Actellic dust and black pepper powder had significantly low percentages of damaged seeds. Black pepper powder and coconut oil showed good potential in protecting cowpea against bruchid damage.

Bromus species are annual winter weeds from the Poaceae family which have become troublesome weeds of winter cereals. The herbicides propoxycarbazone and pyroxsulam are widely used for control of B. sterilis. The objective of this study was to determine the effect of different types of adjuvants and carriers on the efficacy of pyroxsulam and propoxycarbazone on B. sterilis. Small plot field trials were carried out in North Bohemia, Central Europe during 2011-2013. The tested carriers and adjuvants affected the efficacy of both herbicides and the seed production of B. sterilis. Urea ammonium nitrate was a less effective carrier than water (differences 5-30%). The most effective adjuvant was methylated seed oil (MSO), whose addition into the application water solution increased the herbicide efficacy of propoxycarbazone by 5-35%. Efficacy of the herbicide pyroxsulam was increased by adjuvant MSO by 10-30%. Nonionic surfactant increased herbicide efficacy only in 2013 (by 17%). Effect of organosilicone surfactant on the herbicide efficacy was negative (lower efficacy). Seed production of B. sterilis on untreated plots ranged between 20 000 and 50 000 seeds/m2 in experimental years. Seed production was the lowest on plots treated by the herbicide plus MSO (1300-4500 seed/m2).