John Wangoh

Iso-electric focusing of camel milk proteins

(Received 18 November 1997; accepted 27 June 1998) The procedure for phenotyping of most genetic variants in cow milk was optimised for iso-electric focusing (IEF) of camel milk proteins and milk from individual camels of different breeds was screened. The caseins obtained from IEF bands were also investigated by Nterminal sequencing. Camel milk casein was separated at different pH and the proteins in the whey obtained were then separated by IEF. Above pH 4.3 casein bands were observed in the whey. According to the pattern of protein bands in IEF, the 103 camels screened had one of the three main groups of milk designated aa, ab and, bb. A small number of camels differed from bb milk type by an extra band and this group was designated as bb l . The high frequency of particular milk type in some breeds suggests that their production characteristics could be related to the phenotypes.

Lactic acid bacteria and yeasts involved in the fermentation ofamabere amaruranu, a Kenyan fermented milk.

Indigenous fermented milk products contain microbiota composed of technologically important species and strains which are gradually getting lost with new technologies. We investigated the microbial diversity inamabere amaruranu, a traditionally fermented milk product from Kenya. Sixteen samples of the product from different containers were obtained. One hundred and twenty isolates of lactic acid bacteria (LAB) and 67 strains of yeasts were identified using API 50 CH and API 20 C AUX identification kits, respectively. The average pH of all the traditional fermented samples was 4.00 ± 0.93. Lactobacilli, yeasts, and molds as well asEnterobacteriaceae counts from the plastic containers were significantly higher (P < 0.05) than those from gourd.Enterobacteriaceae were below 1.00 ± 1.11 log10 cfu/mL in products from the gourds and 2.17 ± 1.92 log10 cfu/mL from the plastic containers. The LAB species were identified asStreptococcus thermophilus (25%),Lactobacillus plantarum (20%), andLeuconostoc mesenteroides (20%). The predominant yeasts wereSaccharomyces cerevisiae (25%),Trichosporum mucoides (15%),Candida famata (10%), andCandida albicans (10%). The type of vessel used for fermentation had no significant influence on the type of isolated and identified species. The diverse mixture of LAB and yeasts microflora forms a potential consortium for further product innovation inamabere amaruranu and other fermented milk products.

Risk factors for symptoms of gastrointestinal illness in rural town Isiolo, Kenya.

This study assesses risk factors for food‐borne gastrointestinal illness indicated by diarrhoea and/or vomiting using 14‐day recalls among children and young adults. The study was set in Isiolo, a rural town of Kenya, inhabited mainly by pastoralists of different ethnic groups. The preparation methods of milk at the household level were also investigated. The study was cross‐sectional and involved 900 participants from randomly selected households. They were interviewed using a structured questionnaire. An unmatched nested case‐control study was constructed by randomly selecting three controls for each case. Potential risk factors for gastrointestinal illness were analysed using both univariate and multivariate logistic regression models with random effect on ethnic groups. The study results showed that consumption of mutton, carrots, Irish potatoes, raw camel milk, boiled camel milk and fermented camel milk were important risk factors for diarrhoea and/or vomiting, whereas the consumption of boiled goat milk, boiled cow milk, spinach, washing of hands with soap and the presence of proper drainage system had protective effects (odds ratio < 1). We conclude that in this setting, primarily vegetables and the camel milk market chain pose the greatest risks for symptoms of food‐borne gastrointestinal illness.

Biodiversity and enterotoxigenic potential of staphylococci isolated from raw and spontaneously fermented camel milk.

Aims: To characterise the diversity, genotypic and phenotypic properties of coagulase negative and coagulase positive staphylococci from camel milk. Place and Duration of Study: Laboratory of Food Biotechnology, Department of Health Sciences and Technology (D-HEST), Swiss Federal Institute of Technology, Zurich, Switzerland, between July 2009 and June 2011. Methodology: Staphylococci isolated from 59 raw and spontaneously fermented camel milk (suusac) samples from Kenya and Somalia were identified, pheno- and genotypically characterized. Preliminary screening of colonies was done by catalase test, Gram staining reactions, clumping factor/protein A and microscopy. Further identification was done by 23S rDNA species PCR, thermostable nuclease gene (nuc) PCR and rep-PCR followed by staphylococcal genus ID32 Staph system and coagulase negative species specific PCR. PCR amplification of the genes encoding capsular polysaccharides cap5 and cap8, and staphylococcal enterotoxins SEA to SEE and SEG to SEJ was also carried out. Results: From a total of 235 BP medium isolates, staphylococci were 146 (62 %) of which, 66 (45 %) were Staphylococcus aureus. S. epidermidis accounted for 43 % of the coagulase negative staphylococci (CNS). The rest of the CNS were 25 % S. simulans, 16.3 % S. saprophyticus, 2.5 % S. haemolyticus, 2.5% S. hyicus, 2.5 % S. xylosus, 2.5 % S. lentus, 1.3 % S. carnosus and 1.3 % S. microti. Capsular polysaccharide gene cap5 was present in 15 % and cap8 in 23 % of the S. aureus isolates. Enterotoxin genes were detected in 47 % of the staphylococci with sej in 33 %, seb in 6 %, sed in 5 % and seg in 3 % of the isolates. Within the species enterotoxin genes were detected in 100 %, 64.7 %, 38.5 % and 22.7 % of the S. simulans, S. epidermidis, S. sapropyticus and S. aureus respectively. Conclusion: The diversity of CNS is remarkable and the prevalence of enterotoxin genes amongst CNS and CPS further informs generalizations for other milk and hygienic situations in similar production environment.

Current Food Safety Management Systems in Fish‐Exporting Companies Require Further Improvements to Adequately Cope with Contextual Pressure: Case Study

UNLABELLED Fish-processing plants still face food safety (FS) challenges worldwide despite the existence of several quality assurance standards and food safety management systems/s (FSMSs). This study assessed performance of FSMS in fish exporting sector considering pressure from the context in which they operate. A FSMS diagnostic tool with checklist was used to assess the context, FSMS, and FS output in 9 Kenyan fish exporting companies. Majority (67%) companies operated at moderate- to high-risk context but with an average performance in control and assurance activities. This situation could be insufficient to deal with ambiguity, uncertainty, and vulnerability issues in the context characteristics. Contextual risk posed by product characteristics (nature of raw materials) and chain environment characteristics was high. Risk posed by the chain environment characteristics, low power in supplier relationships, and low degree of authority in customer relationships was high. Lack of authority in relationship with suppliers would lead to high raw material risk situation. Even though cooling facilities, a key control activity, was at an advanced level, there was inadequate packaging intervention equipment which coupled with inadequate physical intervention equipment could lead to further weakened FSMS performance. For the fish companies to improve their FSMS to higher level and enhance predictability, they should base their FSMS on scientific information sources, historical results, and own experimental trials in their preventive, intervention, and monitoring systems. Specific suggestions are derived for improvements toward higher FSMS activity levels or lower risk levels in context characteristics. PRACTICAL APPLICATION Weak areas in performance of control and assurance activities in export fish-processing sector already implementing current quality assurance guidelines and standards were studied taking into consideration contextual pressure wherein the companies operate. Important mitigation measures toward improved contextual risk, core assurance, and control activities irrespective of applied food safety management systems in fish industries were suggested.

Semiquantitative analysis of gaps in microbiological performance of fish processing sector implementing current food safety management systems: a case study.

Fish processing plants still face microbial food safety-related product rejections and the associated economic losses, although they implement legislation, with well-established quality assurance guidelines and standards. We assessed the microbial performance of core control and assurance activities of fish exporting processors to offer suggestions for improvement using a case study. A microbiological assessment scheme was used to systematically analyze microbial counts in six selected critical sampling locations (CSLs). Nine small-, medium- and large-sized companies implementing current food safety management systems (FSMS) were studied. Samples were collected three times on each occasion (n = 324). Microbial indicators representing food safety, plant and personnel hygiene, and overall microbiological performance were analyzed. Microbiological distribution and safety profile levels for the CSLs were calculated. Performance of core control and assurance activities of the FSMS was also diagnosed using an FSMS diagnostic instrument. Final fish products from 67% of the companies were within the legally accepted microbiological limits. Salmonella was absent in all CSLs. Hands or gloves of workers from the majority of companies were highly contaminated with Staphylococcus aureus at levels above the recommended limits. Large-sized companies performed better in Enterobacteriaceae, Escherichia coli, and S. aureus than medium- and small-sized ones in a majority of the CSLs, including receipt of raw fish material, heading and gutting, and the condition of the fish processing tables and facilities before cleaning and sanitation. Fish products of 33% (3 of 9) of the companies and handling surfaces of 22% (2 of 9) of the companies showed high variability in Enterobacteriaceae counts. High variability in total viable counts and Enterobacteriaceae was noted on fish products and handling surfaces. Specific recommendations were made in core control and assurance activities associated with sampling locations showing poor performance.

Phenotypic and genotypic antibiotic resistance patterns of Staphylococcus aureus from raw and spontaneously fermented camel milk.

Aims: To pheno-and genotypically characterise Staphylococcus aureusisolated from raw and fermented camel milk from Kenya and Somali for their antibiotic resistance. Methodology: Microdilution assays to determine minimal inhibitory concentratio ns (MICs) were done using to 20 different antibiotics. Further tests with selected antibiotics were done using disk diffusion test. Genotypic antibiotic resistance was tested using by microarray hybridization with selected isolates and consequent screening of antibiotic resistance genes by PCR. Results: Prevalence of antibiotic resistance among the 47 S. aureus tested were ampicillin 26% (12), gentamicin 26% (12), streptomycin 11% (5), tetracycline 13% (6), trimethoprim 6% (3) and fusidic acid 2% (1). Multi -resistance was detected with three isolates resistant to two antibiotics, six to three antibiotics and six to four or more

Detection, isolation and molecular characterisation of shigatoxigenic O157 and non-O157 Escherichia coli in raw and fermented camel milk.

Prevalence and distribution of Escherichia coli O157 and non-O157 Shiga toxin-producing Escherichia coli (STEC) in samples collected along raw and fermented camel milk marketing chain was assessed. A combination of culture media and immunomagnetic separation followed by typing for associated virulence factors and serotypes was performed. Thirty six percent (36%) of the isolates haboured either single or combinations of stx1, stx2 and eae with 77.7% being stx1-positive, 18.5% eae-positive, 3.1% stx1 and stx2-positive and 0.8% stx2 and eae-positive. The highest percentage (56.5%) of presumptive E. coli isolates was isolated from EMB agar while CHROM agar and CT-SMAC enabled the detection of 23 and 20.5% of isolates, respectively. However, 100, 38.6 and 12.3% of isolates from CT-SMAC, EMB agar and CHROMagar, respectively were found to be STEC. Serotypes O157, O111 and O113 represented 94, 2 and 4% of the STEC, respectively. A higher prevalence of STEC found in camel milk in the current study compared to milk samples in other countries from other animal species indicates that the milk could be an important vehicle for transmission of STEC to humans.

Design and Performance Assessment of a Low Cost Evaporative Cooler for Storage of Camel Milk in Arid Pastoral Areas of Kenya

A low-cost charcoal evaporative cooler was designed and tested for the storage of camel milk in an arid pastoral area of northern Kenya. The cooler, 0.75 m3 in capacity, was made of galvanised iron frame reinforced with wire mesh inside and out, leaving a 10 cm-wide cavity which was filled with charcoal. A water reservoir linked to the cooler at the top through a perforated pipe kept the charcoal continuously wet through drip system. A wind driven fan on the roof enhanced air movement through the charcoal walls by sucking out the air in the cooler. The cooler was evaluated for temperature and product response. The inside temperature was 1-11°C lower than outside temperature and inside humidity was 0-49% higher than outside. During the hottest time of the day (14.00 hrs) when cooling was most needed, the cooler consistently maintained an average temperature drop of 10.5±0.4°C below ambient temperature, which varied from 29-32°C. This reduction in temperature was 35.6% and statistically significant (p≤0.05). During this time, cooling efficiency varied between 74.2 to 86.7%. Temperature of camel milk inside the cooler did not significantly increase (p>0.05) between morning time and evening time. However, temperature of control milk at ambient conditions significantly (p≤0.05) changed over the same period, from 22.6±0.08°C to 28.1±0.08°C. Milk inside the cooler was also significantly cooler (p≤0.05) than control milk in the evening, with a net temperature reduction of 27.0%. Total bacterial count changed from 31.4±2.1 x 104 cfu/ml to 43.1±1.9 x 104 and 1638±81 x 104 cfu/ml for test and control milk, respectively, after storage for 10 hours. As an inexpensive alternative to mechanical refrigeration, evaporative cooling technology is promising and suitable for rural application in arid pastoral areas without grid electricity, to minimise risk of milk spoilage at collection points and retail level, and thereby encourage organised women groups to get involved in milk marketing as a source of income.