Sensory characterization of the perceived quality of East African highland cooking bananas (matooke).

BACKGROUND: It has recently become increasingly evident that banana projects in Uganda need to consider consumer preferences as part of the breeding process to increase the acceptability of new cultivars. A trained panel used quantitative descriptive analysis (QDA) as a tool to assess the sensory characteristics of 32 cooking bananas (matooke). The aim was to investigate which sensory characteristics best describe matooke. RESULTS: Fourteen descriptors were generated. The preferred attributes of matooke were high-intensity yellow color, homogeneous distribution of yellow color, good matooke aroma, highly moldable by touch, moist and smooth in the mouth. Analysis of variance revealed significant differences in the yellowness, homogeneity of color, firmness, moistness, smoothness, matooke aroma, hardness, and moldability across the genotypes (P < 0.05). Principal component analysis (PCA) showed strong positive correlations between yellowness and homogeneity of the color (R = 0.92). Smoothness in the mouth and moldability by touch were strongly and positively correlated (R = 0.88). Firmness in the mouth was well predicted by hardness to touch (R2 = 0.85). The matooke samples were ranked into two sensory clusters by agglomerative hierarchical clustering (AHC). CONCLUSION: The study showed attribute terms that could be used to describe matooke and also revealed that QDA may be used as a tool during the assessment and selection of new cooking banana hybrids to identify relevant sensory attributes because of its ability to discriminate among the banana hybrids. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Internal Quality Assessment of East African Highland Cooking Banana (Musa spp.) Flour: Significance for Breeding and Industrial Applications.

This study assessed the internal quality traits of East African Highland cooking banana flours, exploring their significance for breeding and potential industrial applications. Twenty cultivars (nine hybrids and eleven landraces) were used. Swelling power capacity, water solubility, water absorption capacity, water absorption index, freeze-thawing stability, and pasting characteristics of banana flour were assessed using standard methods. The results showed that cultivars with high swelling power also exhibited a high water absorption capacity and water absorption index, thus making them suitable for bakery industries. The water absorption capacity ranged between 5.66% (N2) and 11.68% (N11). Landraces KBZ (9.01) and NKYK (8.05), and hybrids N11 (11.68) and N9 (8.48) are suitable as thickeners due to high WAC. Hybrids (N7, 27.83%, and N9, 22.59%) and landraces (NMZ, 32.69%, and NFK, 34.24%) had low freeze-thawing stability, hence it is applicable as a food stabilizer. Landrace NKT (19.14%) and hybrid N9 (16.95%) had the highest solubility, and landrace KBZ (6.93%) and hybrid N3 (6.66%) had the lowest solubility. Landraces MSK (6265), NKY (3980), and NFK (3957), and hybrids N6 (3608), N7 (3505), and N9 (3281 RVU) had high peak viscosity. The trough viscosity, final viscosity, and breakdown viscosity of cultivars varied from 422.5 to 5004 RVU. The landraces MSK (5021 RVU) and NFK (4111 RVU) had the highest final viscosity, making them suitable for application in the food industry for thick and stable sauces. Landrace TRZ had the lowest pasting temperature (62.7 °C), making it advantageous for use where fast gelatinization is required, hence saving energy costs and cooking time. These findings suggest that the genetic attributes inherent in cultivars can be incorporated into breeding programs targeting required traits for industrial application.

Probiotic Potential of Lactic Acid Starter Cultures Isolated from a Traditional Fermented Sorghum-Millet Beverage.

The purpose of this study was to establish the probiotic potential of lactic acid bacteria (LAB) starter cultures, Lb. plantarum MNC 21, L. lactis MNC 24, and W. confusa MNC 20, isolated from a traditionally fermented sorghum-millet beverage from Uganda. The cultures were examined for tolerance to acid and bile salts, bile salt hydrolase (BSH) activity, antibiotic susceptibility, biogenic amine production, mucin degradation, hydrophobicity, auto-aggregation, adherence to the ileum, coaggregation, and antimicrobial properties against selected pathogenic species. Lb. rhamnosus yoba 2012, a known probiotic, was the reference. The isolates were tolerant to acid (pH = 3) and bile (1%). W. confusa MNC 20 and Lb. plantarum MNC 21 exhibited medium BSH activity (11-15 mm diameter of hydrolysis zone) while L. lactis and Lb. rhamnosus yoba 2012 exhibited low BSH activity (<10 mm diameter of hydrolysis zone). All isolates lacked mucolytic activity. Lb. plantarum MNC 21 and W. confusa MNC 20 produced agmatine. The candidate and reference microorganisms were resistant to 10 of 21 and 5 of 21 antibiotics, respectively. The isolates exhibited hydrophobic, auto-aggregation and coaggregation properties. These three properties were exhibited more (p < 0.05) by the reference than the potential probiotics. The ability of the potential probiotics to attach onto the goat ileum (7.3-8.0 log cfu/cm2) was comparable to that of Lb. rhamnosus yoba 2012 (7.6 log cfu/cm2). The four LAB inhibited E. coli, S. aureus, and S. enterica to the same extent (p < 0.05). The findings indicated potential probiotic activity of the starter cultures. However, further in vivo examination of these isolates is required to confirm their probiotic capabilities.

Comparison of the microbial composition of African fermented foods using amplicon sequencing.

Fermented foods play a major role in the diet of people in Africa, where a wide variety of raw materials are fermented. Understanding the microbial populations of these products would help in the design of specific starter cultures to produce standardized and safer foods. In this study, the bacterial diversity of African fermented foods produced from several raw materials (cereals, milk, cassava, honey, palm sap, and locust beans) under different conditions (household, small commercial producers or laboratory) in 8 African countries was analysed by 16S rRNA gene amplicon sequencing during the Workshop "Analysis of the Microbiomes of Naturally Fermented Foods Training Course". Results show that lactobacilli were less abundant in fermentations performed under laboratory conditions compared to artisanal or commercial fermentations. Excluding the samples produced under laboratory conditions, lactobacilli is one of the dominant groups in all the remaining samples. Genera within the order Lactobacillales dominated dairy, cereal and cassava fermentations. Genera within the order Lactobacillales, and genera Zymomonas and Bacillus were predominant in alcoholic beverages, whereas Bacillus and Lactobacillus were the dominant genera in the locust bean sample. The genus Zymomonas was reported for the first time in dairy, cereal, cassava and locust bean fermentations.

Antimicrobial Activity of Lactic Acid Bacteria Starters against Acid Tolerant, Antibiotic Resistant, and Potentially Virulent E. coli Isolated from a Fermented Sorghum-Millet Beverage.

Bacterial contamination of fermented foods is a serious global food safety challenge that requires effective control strategies. This study characterized presumptive E. coli isolated from Obushera, a traditional fermented cereal beverage from Uganda. Thereafter, the antimicrobial effect of lactic acid bacteria (LAB) previously isolated from Obushera, against the E. coli, was examined. The presumptive E. coli was incubated in brain heart infusion broth (pH = 3.6) at 25°C for 48 h. The most acid-stable strains were clustered using (GTG)5 rep-PCR fingerprinting and identified using 16S rRNA sequencing. E. coli was screened for Shiga toxins (Stx 1 and Stx 2) and Intimin (eae) virulence genes as well as antibiotic resistance. The spot-on-the-lawn method was used to evaluate antimicrobial activity. Eighteen isolates were acid stable and are identified as E. coli, Shigella, and Lysinibacillus. The Stx 2 gene and antibiotic resistance were detected in some E. coli isolates. The LAB were antagonistic against the E. coli. Lactic acid bacteria from traditional fermented foods can be applied in food processing to inhibit pathogens. Obushera lactic acid bacteria could be used to improve the safety of fermented foods.

Production of organic flavor compounds by dominant lactic acid bacteria and yeasts from Obushera, a traditional sorghum malt fermented beverage.

Single and mixed starter cultures of lactic acid bacteria (LAB): Weissella confusa MNC20, Lactobacillus plantarum MNC21, Lactococcus lactis MNC24 and Lactobacillus fermentum MNC34 and yeasts: Issatchenkia orientalis MNC20Y and Saccharomyces cerevisiae MNC21Y were used to produce Obushera, a fermented sorghum beverage. Microbial counts, pH, sugars, organic acids, and volatile compounds in starter culture and spontaneous fermentations were monitored during 48 hrs. Maximum counts of LAB (8.4-9.4 log cfu g-1) and yeasts (7.5 ± 0.1 cfu g-1) starter cultures were attained in 6-48 hrs. Weissella confusa, Lc. lactis, and Lb. fermentum showed possible acid sensitivity while I. orientalis produced surface films. LAB starter cultures and their combinations with S. cerevisiae lowered pH from 5.83 to <4.5 (3.50-4.13) in a shorter time (12 hrs) than spontaneous fermentations (24 hrs). Lactococcus lactis and W. confusa metabolized glucose the fastest (p < .05) during the first 6 hrs. Lactobacillus fermentum, Lb. plantarum, and S. cerevisiae utilized glucose and maltose concurrently. Lactobacillus plantarum and S. cerevisiae additionally utilized fructose. S. cerevisiae metabolized sugars the fastest (p < .05) during the first 12-24 hrs. Lactobacillus plantarum and W. confusa produced the highest (p < .05) amounts of lactate (5.43 g kg-1) and diacetyl (9.5 mg kg-1), respectively. LAB also produced acetate, ethanol, acetaldehyde, acetone, and acetoin. Coculturing LAB with S. cerevisiae reduced (p < .05) lactate and diacetyl yield. Yeasts produced high amounts of acetaldehyde and methyl alcohols. Issatchenkia orientalis produced higher (p < .05) amounts of 2-methy-1-propanol and 3-methyl-1-butanol than S. cerevisiae. Combinations of LAB with S. cerevisiae produced a profile flavor compounds close to that of spontaneously fermented Obushera. These combinations can be adopted for controlled fermentation of Obushera and related fermented cereal products.

Sociocultural factors associated with fish consumption in Lake Albert fishing community: Guidelines for lead and mercury.

Fish consumption in subsistence fishing community is a life style associated with lead and mercury uptake for humans. Fish consumption is influenced by sociocultural factors, exposure and health risks. Unfortunately, no sociocultural study in the Lake Albert fishing community in light of lead and mercury exists. A cross-sectional sociocultural study was carried out between March and June 2015. A total of 270 household heads in four landing sites in Hoima district completed structured questionnaires and data analyzed using SPSS version 20. The majority of the households (74.8%) had primary education or below, 51.1% drank unboiled water, and 30% perceived lake water safe for drinking. Children under five ate soup (15%) and middle piece of the fish (29%). The Poisson general linear model predicting weekly fish consumption amounts against sociocultural factors showed that household size (p = 0.047), male child presence (p = 0.007), methods of preparation i.e. salting (p < 0.0001), fish parts consumed by adults (p < 0.0001), fish preference (p < 0.0001), awareness about the beach management unit (p < 0.0001), and income from charcoal selling (p < 0.0001) were positive predictors. The negative predictors of weekly fish consumption amounts were awareness about fish consumption benefits (p < 0.0001), eating young fish (p = 0.002), donor agency presence (p < 0.0001), and frying as the method of fish preparation (p = 0.002). In conclusion, knowledge of the sociocultural factors associated with fish consumption determines the amounts and frequency of the predominant fish eaten. Therefore, to establish and adopt fish consumption guidelines for lead and mercury in the Lake Albert, the sociocultural factors should be integrated in the message disseminated.

Fate of Escherichia coli O157:H7 and Salmonella enterica in the manure-amended soil-plant ecosystem of fresh vegetable crops: a review.

Enterohemorrhagic Escherichia coli (EHEC) and Salmonella enterica have been implicated in several disease outbreaks linked to consumption of fresh vegetables. Both ruminant and non-ruminant animals carry EHEC and S. enterica in their gastrointestinal tracts and can shed the pathogens in the faecal matter both in symptomatic and asymptomatic states. Application of animal waste in soil fertility management and irrigation of crops with contaminated waste water has been recognised as an important route through which EHEC and S. enterica can contaminate fresh vegetables during primary production. The behavior of E. coli O157:H7 and S. enterica in the agricultural environment has been extensively studied in the last decades. Several microbiological detection methods have been applied. This review therefore puts together current knowledge on the behavior of E. coli O157:H7 and S. enterica in the manure-amended soil-plant ecosystem of fresh vegetable crops during cultivation under various environmental conditions. The review focuses on methodological issues involved in undertaking survival studies and makes comparative analysis of experimental results obtained from studies conducted under controlled environmental conditions integrating results obtained from field experiments. Finally, a theoretical discussion on the potential likely impact of climate change on pre-harvest safety of field-cultivated vegetables is highlighted.

The dominant microbial community associated with fermentation of Obushera (sorghum and millet beverages) determined by culture-dependent and culture-independent methods.

Obushera includes four fermented cereal beverages from Uganda namely: Obutoko, Enturire, Ekitiribita and Obuteire, whose microbial diversity has not hitherto been fully investigated. Knowledge of the microbial diversity and dynamics in these products is crucial for understanding their safety and development of appropriate starter cultures for controlled industrial processing. Culture-dependent and culture-independent techniques including denaturating gradient gel electrophoresis (DGGE) and mixed DNA sequencing of polymerase chain reaction (PCR) amplified ribosomal RNA genes were used to study the bacteria and yeast diversity of Obushera. The pH dropped from 6.0-4.6 to 3.5-4.0 within 1-2 days for Obutoko, Enturire and Obuteire whereas that of Ekitiribita decreased to 4.4 after 4 days. Counts of lactic acid bacteria (LAB) increased from 5.0 to 11.0 log cfug(-1) and yeasts increased from 3.4 to 7.1 log cfug(-1) while coliform counts decreased from 2.0 to <1 log cfug(-1) during four days of fermentation. LAB and yeast isolates were identified by rRNA gene sequence analysis. LAB isolates included: Enterococcus spp., Lactobacillus (Lb.) plantarum, Lb. fermentum, Lb. delbrueckii, Lactococcus lactis, Leuconostoc lactis, Streptococcus (S.) infantarius subsp. infantarius, Pediococcus pentosaceus and Weisella (W.) confusa. DGGE indicated predominance of S. gallolyticus, S. infantarius subsp. infantarius, Lb. fermentum, Lb. delbrueckii, W. confusa, Lb. reuteri, Fructobacillus spp., L. lactis and L. lactis. Yeast isolates included Clavispora lusitaniae, Cyberlindnera fabianii, Issatchenkia orientalis and Saccharomyces cerevisiae. DGGE indicated predominance of S. cerevisiae in Obutoko, Enturire and Obuteire and also detected Pichia spp. and I. orientalis in Obutoko. Obushera produced in the laboratory was initially dominated by Enterobacteriaceae and later by Lactococcus spp. Enterobacteriaceae and Bacillus spp. were also detected in Ekitiribita. Development of starters for Obushera may require combinations of LAB and S. cerevisiae for Obutoko, Enturire and Obuteire and LAB for Ekitiribita.

Influence of cofermentation by amylolytic Lactobacillus plantarum and Lactococcus lactis strains on the fermentation process and rheology of sorghum porridge.

Amylolytic lactic acid bacteria (ALAB) can potentially replace malt in reducing the viscosity of starchy porridges. However, the drawback of using ALAB is their low and delayed amylolytic activity. This necessitates searching for efficient ALAB and strategies to improve their amylolytic activity. Two ALAB, Lactobacillus plantarum MNC 21 and Lactococcus lactis MNC 24, isolated from Obushera, were used to ferment starches in MRS broth: sorghum, millet, sweet potato, and commercial soluble starch. The amylolytic activity of MNC 21 was comparable to that of the ALAB collection strain Lb. plantarum A6, while that of MNC 24 was extremely low. MNC 21, MNC 24, and their coculture were compared to A6 and sorghum malt for ability to ferment and reduce the viscosity of sorghum porridge (11.6% dry matter). ALAB and the coculture lowered the pH from 6.2 to <4.5 within 12 h, while malt as a carrier of wild starter took about 20 h. Coculturing increased lactic acid yield by 46% and 76.8% compared to the yields of MNC 21 and MNC 24 monocultures, respectively. The coculture accumulated significantly larger (P < 0.05) amounts of maltose and diacetyl than the monocultures. Sorghum malt control and the coculture hydrolyzed more starch in sorghum porridge than the monocultures. The coculture initiated changes in the rheological parameters storage modulus (G'), loss modulus (G″), phase angle (δ), and complex viscosity (η*) earlier than its constituent monocultures. The shear viscosity of sorghum porridge was reduced significantly (P < 0.05) from 1950 cP to 110 cP (malt), 281 cP (coculture), 382 cP (MNC 21), 713 cP (MNC 24), and 722 cP (A6). Coculturing strong ALAB with weak ALAB or non-ALAB can be exploited for preparation of nutrient-dense weaning foods and increasing lactic acid yield from starchy materials.

Contribution of street foods to the dietary needs of street food vendors in Kampala, Jinja and Masaka districts, Uganda.

OBJECTIVES: To assess the contribution of street foods to the energy and nutrient needs of street food vendors. DESIGN: A cross-sectional descriptive study was conducted. Food intake for the street food vendors was measured using the 24 h recall method and a semi-quantitative FFQ with emphasis on the source of all foods consumed. SETTING: Kampala, Jinja and Masaka districts, Uganda. SUBJECTS: The study included 225 street food vendors trading in prepared cooked foods. RESULTS: The majority of vendors (87·6 %) were women with age range of 21-50 years. Traditional dishes were the most commonly prepared foods and classified into main meals, sauces, vegetables and snacks. The food groups consumed most commonly by street food vendors fall under energy-giving and body-building foods (0·26 (sd 0·81)). The mean daily intake of energy from street foods varied between 22·4 % and 25·6 % (2412 kJ). Carbohydrates contributed the highest proportion of energy (70·1 % to 93·4 %), followed by protein (38·6 % to 44·9 %) and fat (21·9 % to 26·3 %). Street food vendors obtained 24·0 % to 32·5 % of their RDA for Ca from street vended foods, with the lowest intake in Jinja (11·2 % to 23·9 %, P < 0·05). Niacin and thiamin intakes from street foods were respectively above 74 % and 150 % of the RDA. The contribution of street foods to the RDA for Zn ranged from 81·9 % to 190·9 %, and from 3·5 % to 4·9 % for retinol. Fe intake from street vended foods was 40·9 % to 49·7 % of the RDA. CONCLUSIONS: Street foods contribute to sources of dietary energy and other nutrients among street food vendors in Uganda.

Rhizosphere effect on survival of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in manure-amended soil during cabbage (Brassica oleracea) cultivation under tropical field conditions in Sub-Saharan Africa.

The effect of cabbage (Brassica oleracea) rhizosphere on survival of Escherichia coli O157:H7 and Salmonella Typhimurium in manure-amended soils under tropical field conditions was investigated in the Central Agro-Ecological Zone of Uganda. Three-week old cabbage seedlings were transplanted and cultivated for 120 days on manure-amended soil inoculated with 4 or 7 log CFU/g non-virulent E. coli O157:H7 and S. Typhimurium. Cabbage rhizosphere did not affect survival of the 4log CFU/g inocula in manure-amended soil and the two enteric bacteria were not detected on/in cabbage leaves at harvest. The 7 log CFU/g E. coli O157:H7 and S. Typhimurium survived in bulk soil for a maximum of 80 and 96 days, respectively, but the organisms remained culturable in cabbage rhizosphere up to the time of harvest. At 7 log CFU/g inoculum, E. coli O157:H7 and S. Typhimurium contamination on cabbage leaves occurred throughout the cultivation period. Leaf surface sterilisation with 1% AgNO(3) indicated that the organisms were present superficially and in protected locations on the leaves. These results demonstrate that under tropical field conditions, cabbage rhizosphere enhances the persistence of E. coli O157:H7 and S. Typhimurium in manure-amended soil at high inoculum density and is associated with long-term contamination of the leaves.

Kitchen practices used in handling broiler chickens and survival of Campylobacter spp. on cutting surfaces in Kampala, Uganda.

Cross-contamination during food preparation has been identified as an important factor associated with foodborne illnesses. Handling practices used during preparation of broiler chickens in 31 fast-food restaurants and 86 semisettled street stands (street vendors) were assessed by use of a standard checklist. These establishments used wood, plastic, or metal cutting surfaces during the preparation of broiler chickens. The survival of Campylobacter spp. on kitchen cutting surfaces was determined by inoculating approximately 10(6) CFU of Campylobacter jejuni onto sterile plastic, wooden, and metal cutting boards. The concentrations of the organisms were then assessed in triplicate on each type of cutting board over a 3-h period using standard microbiological methods for thermophilic Campylobacter spp. In 87% of food establishments, the same work area was used for preparation of raw and cooked chicken, and in 68% of these establishments the same cutting boards were used for raw and cooked chicken. None of the establishments applied disinfectants or sanitizers when washing contact surfaces. Campylobacter spp. survived on wooden and plastic but not on metal cutting boards after 3 h of exposure. The handling practices in food preparation areas, therefore, provide an opportunity for cross-contamination of Campylobacter spp. to ready-to-eat foods.