Survey of postharvest handling, preservation and processing practices along the camel milk chain in Isiolo district, Kenya

Despite the important contribution of camel milk to food security for pastoralists in Kenya, little is known about the postharvest handling, preservation and processing practices. In this study, existing postharvest handling, preservation and processing practices for camel milk by pastoralists in Isiolo, Kenya were assessed through crosssectionalsurvey and focus group discussions. A total of 167 camel milk producerhouseholds, 50 primary and 50 secondary milk traders were interviewed. Survey findings showed that milking was predominantly handled by herds-boys (45.0%) or male household heads (23.8%) and occasionally by spouses (16.6%), sons (13.9%) and daughters (0.7%). The main types of containers used by both producers and traders to handle milk were plastic jerricans (recycled cooking oil containers), because they were cheap, light and better suited for transport in vehicles. Milk processing wasthe preserve of women, with fresh camel milk and spontaneously fermented camel milk (suusa) being the main products. Fresh milk was preserved by smoking of milk containers and boiling. Smoking was the predominant practice, and was for extending the shelf life and also imparting a distinct smoky flavour to milk. The milk containerswere fumigated with smoke from burned wood of specific tree species such as Olea africana, Acacia nilotica, Balanities aegyptica and Combretum spp. Boiling was practised by primary milk traders at collection points to preserve milk during times when transport to the market was unavailable. Milk spoilage at the primary collection point in Kulamawe was aggravated by lack of cooling facilities. At the secondary collection point in Isiolo town, milk was refrigerated overnight before onward transmission to Nairobi. The mean quantity of traded milk was 83.2±3.8 litres. The main problems experienced by milk traders in Isiolo included milk spoilage (43.0% ofrespondents), delayed payments—after one or two days (19.9%), loss of money due to informal courier (12.2%), low prices of fermented milk (10.9%), milk rejection by customers in Nairobi (7.1%), inadequate supply during dry season (3.5%), loss of milk due to bursting of containers (2.1%) and milk not being supplied by producers due to insecurity (1.3%). In-depth understanding of the postharvest handling, preservation and processing practices would help to devise appropriate strategies thatwould increase the quantity and improve the quality of marketed camel milk. Such strategies should include the improvement of infrastructure such as milk transport, collection, cooling and processing facilities of suitable capacity

Direct observation of delithiation as the origin of analog memristance in LixNbO2

The discovery of analog LixNbO2 memristors revealed a promising new memristive mechanism wherein the diffusion of Li+ rather than O2- ions enables precise control of the resistive states. However, directly correlating lithium concentration with changes to the electronic structure in active layers remains a challenge and is required to truly understand the underlying physics. Chemically delithiated single crystals of LiNbO2 present a model system for correlating lithium variation with spectroscopic signatures from operando soft x-ray spectroscopy studies of device active layers. Using electronic structure modeling of the x-ray spectroscopy of LixNbO2 single crystals, we demonstrate that the intrinsic memristive behavior in LixNbO2 active layers results from field-induced degenerate p-type doping. We show that electrical operation of LixNbO2-based memristors is viable even at marginal Li deficiency and that the analog memristive switching occurs well before the system is fully metallic. This study serves as a benchmark for material synthesis and characterization of future LixNbO2-based memristor devices and suggests that valence change switching is a scalable alternative that circumvents the electroforming typically required for filamentary-based memristors

Effect of lactoperoxidase-thiocyanate-hydrogen peroxide system and storage temperature on keeping quality of raw camel milk

The use of lactoperoxidase system (LP-system) in temporary preservation of raw milk has been found useful particularly in places where refrigeration is not feasible. The activity of this system, however, varies from species to species and there are no reports on its effect in camel milk. This study was conducted to investigate the preservative effect of the LP-system on raw camel milk. Camel milk samples were obtained from Kajiado, Isiolo and Nanyuki districts, Kenya and LP-system was activated by the addition of hydrogen peroxide (H2O2) to a concentration of 8.5ppm Changes in total viable bacterial counts and titratable acidity in LP-activated and non-activated (control) camel milk were then determined during storage at 10, 20 and 30°C. The combined effect of increasing levels of thiocyanate (NaSCN) and hydrogen peroxide (H2O2 ) on antibacterial activity of LP-system in raw camel milk was investigated at 30°C by monitoring changes in total viable bacterial counts and lactic acid development in raw camel milk at NaSCN:H2O2 concentrations ratios of 0, 10:10, 20:20, 30:30 and 40:40ppms. Natural concentration of thiocyanate occurring in the camel milk from the three districts ranged from 9.7 to 36.4 mg/l and respective districts were significantly different (p<0.05) from each other. No additional amount of thiocyanate was, therefore, used to activate the LP-system. Microbial growth was halted for 15, 17 and 76 hrs at 30, 20 and 10°C, respectively by activation of the LP-system in raw camel milk at 8.5ppm. Viable counts increased significantly (p<0.05) during storage at 10, 20, 30°C conditions. Shelflife was extended by 19 hrs during storage at 10 and 20°C and 4 hours at 30°C. Increased levels of NaSCN and H2O2 significantly (p<0.05)delayed bacterial growth and lactic acid production. Shelflife of the camel milk as determined by lactic acid production was 4 hrs for control and increased to 6, 12, 16 and 16 hrs for NaSCN: H2O2 ratios of 10:10, 20:20, 30:30 and 40:40 ppm, respectively. The present investigation shows that by activating the LP-System, it is possible to extend the storage period of raw camel milk and that the effect of the LP-System on the microbes varies with temperature of storage and levels of thiocyanate and H2O2. Practical application would be achieved by controlled activation using commercial LP-system kits for pooled camel milk at collection centers and combined with cooling facilities where possible for further extension of keeping quality

Effect Of Lactoperoxidase-Thiocyanate-Hydrogen Peroxide System And Storage Temperature On Keeping Quality Of Raw Camel Milk

The use of lactoperoxidase system (LP-system) in temporary preservation of raw milk has been found useful particularly in places where refrigeration is not feasible. The activity of this system, however, varies from species to species and there are no reports on its effect in camel milk. This study was conducted to investigate the preservative effect of the LP-system on raw camel milk. Camel milk samples were obtained from Kajiado, Isiolo and Nanyuki districts, Kenya and LP-system was activated by the addition of hydrogen peroxide (H2O2) to a concentration of 8.5ppm Changes in total viable bacterial counts and titratable acidity in LP-activated and non-activated (control) camel milk were then determined during storage at 10, 20 and 30°C. The combined effect of increasing levels of thiocyanate (NaSCN) and hydrogen peroxide (H2O2 ) on antibacterial activity of LP-system in raw camel milk was investigated at 30°C by monitoring changes in total viable bacterial counts and lactic acid development in raw camel milk at NaSCN:H2O2 concentrations ratios of 0, 10:10, 20:20, 30:30 and 40:40ppms. Natural concentration of thiocyanate occurring in the camel milk from the three districts ranged from 9.7 to 36.4 mg/l and respective districts were significantly different (p<0.05) from each other. No additional amount of thiocyanate was, therefore, used to activate the LP-system. Microbial growth was halted for 15, 17 and 76 hrs at 30, 20 and 10°C, respectively by activation of the LP-system in raw camel milk at 8.5ppm. Viable counts increased significantly (p<0.05) during storage at 10, 20, 30°C conditions. Shelflife was extended by 19 hrs during storage at 10 and 20°C and 4 hours at 30°C. Increased levels of NaSCN and H2O2 significantly (p<0.05)delayed bacterial growth and lactic acid production. Shelflife of the camel milk as determined by lactic acid production was 4 hrs for control and increased to 6, 12, 16 and 16 hrs for NaSCN: H2O2 ratios of 10:10, 20:20, 30:30 and 40:40 ppm, respectively. The present investigation shows that by activating the LP-System, it is possible to extend the storage period of raw camel milk and that the effect of the LP-System on the microbes varies with temperature of storage and levels of thiocyanate and H2O2. Practical application would be achieved by controlled activation using commercial LP-system kits for pooled camel milk at collection centers and combined with cooling facilities where possible for further extension of keeping quality

Effect of lactoperoxidase-thiocyanate-hydrogen peroxide system and storage temperature on keeping quality of raw camel milk

The use of lactoperoxidase system (LP-system) in temporary preservation of raw milk has been found useful particularly in places where refrigeration is not feasible. The activity of this system, however, varies from species to species and there are no reports on its effect in camel milk. This study was conducted to investigate the preservative effect of the LP-system on raw camel milk. Camel milk samples were obtained from Kajiado, Isiolo and Nanyuki districts, Kenya and LP-system was activated by the addition of hydrogen peroxide (H2O2) to a concentration of 8.5ppm Changes in total viable bacterial counts and titratable acidity in LP-activated and nonactivated (control) camel milk were then determined during storage at 10, 20 and 30oC. The combined effect of increasing levels of thiocyanate (NaSCN) and hydrogen peroxide (H2O2 ) on antibacterial activity of LP-system in raw camel milk was investigated at 30ºC by monitoring changes in total viable bacterial counts and lactic acid development in raw camel milk at NaSCN:H2O2 concentrations ratios of 0, 10:10, 20:20, 30:30 and 40:40ppms. Natural concentration of thiocyanate occurring in the camel milk from the three districts ranged from 9.7 to 36.4 mg/l and respective districts were significantly different (

Survey Of Postharvest Handling, Preservation And Processing Practices Along The Camel Milk Chain In Isiolo District, Kenya

Despite the important contribution of camel milk to food security for pastoralists in Kenya, little is known about the postharvest handling, preservation and processing practices. In this study, existing postharvest handling, preservation and processing practices for camel milk by pastoralists in Isiolo, Kenya were assessed through cross-sectional survey and focus group discussions. A total of 167 camel milk producer households, 50 primary and 50 secondary milk traders were interviewed. Survey findings showed that milking was predominantly handled by herds-boys (45.0%) or male household heads (23.8%) and occasionally by spouses (16.6%), sons (13.9%) and daughters (0.7%). The main types of containers used by both producers and traders to handle milk were plastic jerricans (recycled cooking oil containers), because they were cheap, light and better suited for transport in vehicles. Milk processing was the preserve of women, with fresh camel milk and spontaneously fermented camel milk (suusa) being the main products. Fresh milk was preserved by smoking of milk containers and boiling. Smoking was the predominant practice, and was for extending the shelf life and also imparting a distinct smoky flavour to milk. The milk containers were fumigated with smoke from burned wood of specific tree species such as Olea africana , Acacia nilotica , Balanities aegyptica and Combretum spp. Boiling was practised by primary milk traders at collection points to preserve milk during times when transport to the market was unavailable. Milk spoilage at the primary collection point in Kulamawe was aggravated by lack of cooling facilities. At the secondary collection point in Isiolo town, milk was refrigerated overnight before onward transmission to Nairobi. The mean quantity of traded milk was 83.2±3.8 litres. The main problems experienced by milk traders in Isiolo included milk spoilage (43.0% of respondents), delayed payments—after one or two days (19.9%), loss of money due to informal courier (12.2%), low prices of fermented milk (10.9%), milk rejection by customers in Nairobi (7.1%), inadequate supply during dry season (3.5%), loss of milk due to bursting of containers (2.1%) and milk not being supplied by producers due to insecurity (1.3%). In-depth understanding of the postharvest handling, preservation and processing practices would help to devise appropriate strategies that would increase the quantity and improve the quality of marketed camel milk. Such strategies should include the improvement of infrastructure such as milk transport, collection, cooling and processing facilities of suitable capacity

EFFECT OF LACTOPEROXIDASE-THIOCYANATE-HYDROGEN PEROXIDE SYSTEM AND STORAGE TEMPERATURE ON KEEPING QUALITY OF RAW CAMEL MILK

The use of lactoperoxidase system (LP-system) in temporary preservation of raw milk has been found useful particularly in places where refrigeration is not feasible. The activity of this system, however, varies from species to species and there are no reports on its effect in camel milk. This study was conducted to investigate the preservative effect of the LP-system on raw camel milk. Camel milk samples were obtained from Kajiado, Isiolo and Nanyuki districts, Kenya and LP-system was activated by the addition of hydrogen peroxide (H2O2) to a concentration of 8.5ppm Changes in total viable bacterial counts and titratable acidity in LP-activated and non-activated (control) camel milk were then determined during storage at 10, 20 and 30oC. The combined effect of increasing levels of thiocyanate (NaSCN) and hydrogen peroxide (H2O2) on antibacterial activity of LP-system in raw camel milk was investigated at 30ºC by monitoring changes in total viable bacterial counts and lactic acid development in raw camel milk at NaSCN:H2O2 concentrations ratios of 0, 10:10, 20:20, 30:30 and 40:40ppms. Natural concentration of thiocyanate occurring in th

Escherichia coli O157 serotype in beef carcasses post slaughterhouse in Nairobi and Eldoret, Kenya

The research covered three slaughterhouses in Nairobi and Eldoret. The objectives were to assess the prevalence of E. coli O157 serotype contaminated carcasses at dispatch, the possible cross-contamination during transportation, and knowledge, attitude and handling practices that led to increased contamination or bacterial growth. Randomly selected 250 beef carcasses were sampled. Swab samples from a single carcass were obtained from three sites during loading and offloading of meat to carriers. A total of 1500 samples were obtained. E. coli O157 serotype was isolated, and purified using sorbital MacConkey, MacConkey and nutrient agar. Serotyping was by card agglutination test. Oxoid verotoxin test kit was used to test for verotoxin (VT1 and VT2) production. Carrier environment was monitored. Knowledge, attitude and practices of meat transporters were assessed through a semi structured questionnaire and observations. Probability of contamination was modeled and run through Monte Carlo simulation using winBUGS®. Prevalence and data from the questionnaire were analysed using SPSS Ver.17. The contamination prevalence at offloading was significantly higher compared to loading (p = 0.05). The probability of obtaining an E. coli O157 serotype contaminated carcass at Dagoretti, Limuru and Eldoret, respectively, was 14, 16 and 19 at loading and 31, 39 and 66 at offloading per 1000 carcasses handled. The temperature in the meat carrier significantly increased (p = 0.004) during transportation between loading and offloading. The average time taken to transport the meat from the slaughterhouses to the butchery was 65 minutes. About 14 (43.8 %) of the meat transporters had worked in the meat industry for at least 5 years and almost an equal number 13 (40.4%) had had formal training on meat hygiene. About 53% of meat transporters claimed to wash hands regularly with cold water and soap. Meat carriers were cleaned at the river or in a car wash with cold water and soap only. Carcasses were loaded on the shoulders of the transportation personnel and placed on the floor of the carriers or heaped on top of other carcasses. Offloading at the butchery was done by the same person with no change over of clothes that could be soiled with blood

East and West African milk products are reservoirs for human and livestock-associated Staphylococcus aureus

Staphylococcus aureus frequently isolated from milk products in sub-Saharan Africa (SSA) is a major pathogen responsible for food intoxication, human and animal diseases. SSA hospital-derived strains are well studied but data on the population structure of foodborne S. aureus required to identify possible staphylococcal food poisoning sources is lacking. Therefore, the aim was to assess the population genetic structure, virulence and antibiotic resistance genes associated with milk-derived S. aureus isolates from Côte d'Ivoire, Kenya and Somalia through spa-typing, MLST, and DNA microarray analysis. Seventy milk S. aureus isolates from the three countries were assigned to 27 spa (7 new) and 23 (12 new) MLST sequence types. Milk-associated S. aureus of the three countries is genetically diverse comprising human and livestock-associated clonal complexes (CCs) predominated by the CC5 (n = 10) and CC30 (n = 9) isolates. Panton-Valentine leukocidin, toxic shock syndrome toxin and enterotoxin encoding genes were predominantly observed among human-associated CCs. Penicillin, fosfomycin and tetracycline, but not methicillin resistance genes were frequently detected. Our findings indicate that milk-associated S. aureus in SSA originates from human and animal sources alike highlighting the need for an overarching One Health approach to reduce S. aureus disease burdens through improving production processes, animal care and hygienic measures