This study determined the activities of Bidens pilosa and Moringa oleifera leaf extracts on microbial count of ground beef during 6-day cold storage. Fresh ground beef sample was treated with butylated hydroxytoluene (BHT) (0.2 g/kg), M. oleifera (ML, 1 g/kg) and B. pilosa (BP, 1 g/kg) leaf extracts and compared with the control. The result of the phytochemical contents revealed that ML extract had higher phenolic and flavonoid contents than BP extract (p > 0.05). The antibacterial assay of the extracts revealed an appreciable broad-spectrum activity against tested bacteria with minimum inhibitory concentrations between 0.6 and 10.0 mg/mL. Addition of ML leaf extract to ground beef sample lowered total viable and lactic acid bacteria (p < 0.05) counts than control and BHT treatments at day 3 of storage. These results suggest that ML leaf extract could be used as potential sources of natural antimicrobial agent in meat products.Actividades antimicrobianas in vitro de extractos de hoja de Bidens pilosa y Moringa oleifera y sus efectos en la calidad de ternera triturada durante el almacenamiento en frío RESUMEN Este estudio determinó las actividades de los extractos de hoja de B. pilosa y M. oleifera en los recuentos microbianos de ternera triturada durante 6 días de almacenamiento en frío. Se trató con BHT una muestra fresca de ternera triturada (0,2 g/kg) y extractos de hoja M. oleifera (ML, 1 g/kg) y B. pilosa (BP, 1 g/kg), entonces estos fueron contrastados con la muestra control. Los resultados de los contenidos fitoquímicos revelaron que el extracto de ML tenía un mayor contenido fenólico y de flavonoides en comparación con el extracto de BP (p > 0,05). El ensayo antibacteriano de los extractos reveló una apreciable actividad de amplio espectro frente a las bacterias examinadas con concentraciones inhibitorias mínimas utilizando rangos entre 0,6 y 10,0 mg/mL. La adición de extracto de hoja de ML a la muestra de ternera triturada disminuyó el recuento total viable de bacteria ácido-láctica (p < 0,05) más que en la muestra control y los tratamientos de BHT en tercer día de almacenamiento. Estos resultados sugieren que el extracto de hoja de ML podría ser utilizado como fuente potencial de agente antimicrobiano natural en los productos cárnicos. ARTICLE HISTORY

The study aimed to compare the bacteriological quality of an urban and rural irrigation water source. Bacterial counts, characterization, identification and diversity of aerobic bacteria were determined. Escherichia coli isolated from both sites was subjected to antibiotic susceptibility testing, virulence gene (Stx1/Stx2 and eae) determination and (GTG) 5 Rep-PCR fingerprinting. Low mean monthly counts for aerobic spore formers, anaerobic spore formers and Staphylococcus aureus were noted although occasional spikes were observed. The most prevalent bacterial species at both sites were Bacillus spp., E. coli and Enterobacter spp.Additionally, E. coli and Bacillus spp. were most prevalent in winter and summer respectively. Resistance to at least one antibiotic was 84% (rural) and 83% (urban). Highest resistance at both sites was to cephalothin and ampicillin. Prevalence of E. coli possessing at least one virulence gene (Stx1/Stx2 and eae) was 15% (rural) and 42% (urban). All (rural) and 80% (urban) of E. coli possessing virulence genes showed antibiotic resistance. Complete genetic relatedness (100%) was shown by 47% of rural and 67% of urban E. coli isolates. 1Results from this study show that surface irrigation water sources regardless of geographical location and surrounding land-use practices can be reservoirs of similar bacterial pathogens.

Three Gram-staining-negative, rod-shaped, non-spore-forming, non-motile, oxidase-positive, yellow pigmented and aerobic bacterial isolates designated 8_R23573, 9_R23581 T and 10_R23577 were isolated from raw chicken at a broiler processing plant in Bloemfontein, South Africa. A polyphasic taxonomic approach was used to determine their exact taxonomic identities. Phylogenetic analysis of the 16S rRNA gene sequences showed that the three strains belonged to the genus Chryseobacterium, exhibiting the highest similarities to Chryseobacterium shigense DSM 17126 T (98.6-99.2 %) and Chryseobacterium luteum DSM 18605 T (98.3-98.7 %). The most abundant quinone was menaquinone MK-6 and the predominant cellular fatty acids were iso-15 : 0, iso-17 : 1v9c, iso-17 : 0 3-OH and summed feature 3 (iso-16 : 1v7c and/or iso-15 : 0 2-OH), which supported the affiliation of the strains to the genus Chryseobacterium. The DNA G+C contents of the strains were 36.9, 36.7 and 36.6 mol% respectively. The DNA-DNA hybridization results gave relatedness values ranging from 78.8 to 87.2 % among the three strains and 23.4 to 56.1 % to the two nearest phylogenetic neighbours C. shigense DSM 17126 T and C. luteum LMG 23785 T . On the basis of the data from this polyphasic study, the three strains are concluded to represent a novel species of the genus Chryseobacterium for which the name Chryseobacterium carnipullorum sp. nov. is proposed. The type strain is 9_R23581 T (5LMG 26732 T 5DSM 25581 T ).The genus Chryseobacterium belongs to the family Flavobacteriaceae (Bernardet et al., 2002;Bernardet, 2011). It was described by Vandamme et al. (1994) to accommodate six species formerly classified within the genus Flavobacterium, namely Chryseobacterium balustinum, Chryseobacterium gleum, Chryseobacterium indologenes, Chryseobacterium indoltheticum, Chryseobacterium meningosepticum and Chryseobacterium scophthalmum and was later amended (Kämpfer et al., 2009). The type species is C. gleum. Members of the genus Chryseobacterium include psychrotolerant and proteolytic spoilage micro-organisms that are widely distributed in food sources such as milk, fish, meat and poultry (Hugo et al., 2003;de Beer et al., 2005 de Beer et al., , 2006 and occur in a variety of ecological niches such as soil, water, sludge, plants, and human and fish clinical specimens (Hugo et al., 2003;Bernardet et al., 2005Bernardet et al., , 2011Hugo & Jooste, 2012).In 2006 the genus Chryseobacterium consisted of only 10 validly named species. Since then the genus has undergone significant and rapid expansion and, at the time of writing, it comprises 61 species with validly published names (Bernardet et al., 2006) and more continue to be described (Euzéby, 2012). This can be ascribed to the readily available and improved phenotypic, chemotaxonomic and molecular identification methods used in the polyphasic taxonomic approach.During the course of the characterization of chryseobacterial strains isolated from raw chicken in a previous study (de Beer, 2005) at a poultry processing plan...

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Chryseobacterium species are isolated and taxonomically evaluated from a wide range of sources. While C. gleum and C. indologenes have been implicated in human disease, the potential pathogenicity of numerous other species have not been investigated. The aims were therefore to evaluate 37 Chryseobacterium species and Elizabethkingia meningoseptica from environmental, food, fish, water and clinical sources for production of haemolysis, growth at 37 °C, and production of virulence enzymes. The control of these strains were investigated by determination of antimicrobial and disinfectant resistance. All the species produced α- or β-haemolysis. In terms of growth at 37 °C and production of virulence enzymes, C. soldanellicola (environmental), C. oranimense (food) and C. koreense (natural mineral water) could be potential human pathogens. Chryseobacterium piscium might be pathogenic to fish. Trimethoprim could be the most effective antimicrobial for the treatment of a Chryseobacterium species infection, while the disinfectants that contain poly-dimethyl ammonium chloride or benzalkonium chloride could be regarded as the most effective for decontamination of surfaces contaminated with Chryseobacterium species.

The effect of temperature on the growth kinetics and proteolytic activity of Chryseobacterium joostei and Chryseobacterium bovis was determined during this study. The results were compared with the activities of Pseudomonas fluorescens, which is regarded to be a major food spoilage psychrotolerant microorganism. For the growth studies, cultures were incubated in nutrient broth in a temperature gradient incubator (from 9 to 50 °C) and separately at 4 °C, and the optical density was measured at different time intervals. Growth temperature profiles for each organism were constructed. For determination of proteolytic activity, the cultures were incubated in fat-free ultra-high temperature processed milk in the temperature gradient incubator for 72 h (temperature range as above). Cell-free extracts were used to determine the proteolytic activity using the azocasein method. Results of the growth studies showed that C. joostei had the ability to grow over a wider temperature range than C. bovis and P. fluorescens without being affected by changes in the temperature. For the proteolytic activity, C. joostei had significantly (p < 0.001) higher activity per milligram of protein at 15.5 °C, followed by C. bovis and P. fluorescens. The results showed that C. joostei potentially has an even greater spoilage capacity in milk on the basis of growth rate and proteolytic activity than did P. fluorescens.

Cold-tolerant bacteria, also known as psychrotrophic bacteria, are notorious contaminants of milk in the refrigerated dairy food chain. These organisms, especially the pseudomonads, may produce heat-resistant enzymes that are responsible for the breakdown of proteins and lipids in milk and dairy products. Such reactions result in a variety of defects in the raw or unprocessed milk that may affect the suitability of such milk for further processing. The enzymes produced may cause defects in long-life dairy products such as cheese, butter and long-life milk. In the present study, a range of 18 yellow pigmented psychrotrophic bacteria, collectively known as flavobacteria, were isolated from local dairy products. One aim of this study was to identify these bacteria to species level using molecular techniques. A second aim was to determine the spoilage potential of these organisms based on profiles generated by the BIOLOG system (that may relate to hydrolytic enzymes produced). Of the 18 isolates, 14 belonged to the genus Chryseobacterium while 4 were identified as Empedobacter isolates. The most active spoilage organisms in this group were shown to be C. bovis, C. shigense and E. brevis. These findings illustrate that enzymatically catalysed defects in dairy products should not be attributed solely to acknowledged psychrotrophic bacteria such as the pseudomonads, but that flavobacterial species may also be actively involved.

Strain 7_F195T was previously isolated from chicken feather waste collected from an abattoir in Bloemfontein, South Africa. A polyphasic approach was followed to determine if strain 7_F195T belongs to the genus Chryseobacterium and if the organism can be classified as a new species. The nearest neighbours, based on 16S rRNA gene sequence similarity values (indicated in parentheses), were Chryseobacterium flavum KCTC 12877T (98.42 %), Chryseobacterium indologenes LMG 8337T (98.24 %) and Chryseobacterium gleum ATCC 35910T (97.71 %). Genome sequencing revealed a genome size of 4 796 535 bp and a DNA G+C content of 38.6 mol%. The ANI values of strain 7_F195T compared to C. flavum , C. indologenes and C. gleum were 81.45, 81.86 and 82.38 %, respectively. The digital DNA–DNA hybridization values for strain 7_F195T with C. flavum , C. indologenes and C. gleum were 23.7, 23.7 and 24.9 %, respectively. Notable phenotypic differences include the presence of urease activity in C. indologenes LMG 8337T and C. gleum NCTC 11432T, but not in strain 7_F195T or C. flavum KCTC 12877T. The predominant fatty acids of strain 7_F195T were iso-C15 : 0, iso-C17 : 1 ω9c and iso-C17 : 0 3-OH and the most abundant polar lipid was phosphatidylethanolamine. Menaquinone-6 was the only respiratory quinone. Based on the data generated from this polyphasic study, strain 7_F195T represents a novel Chryseobacterium species for which the name Chryseobacterium pennipullorum sp. nov. is proposed. The type strain is 7_F195T (=LMG 30781T=KCTC 62760T).