How Worried Are You about Food Fraud? A Preliminary Multi-Country Study among Consumers in Selected Sub-Saharan African Countries.

Food fraud is an old, recurring, and global threat to public health. It poses a serious threat to food security in sub-Saharan Africa (SSA). Despite the prevalence of food fraud in SSA, little is known about how food fraud is viewed by consumers. This study aims to provide an overview of consumers' concerns about food fraud in SSA. A multi-country survey was conducted in October 2022-31 January 2023, and 838 valid responses were returned. To reduce the large and correlated dataset, Principal Component Analysis (PCA) was used. Five components were derived from PCA: (i) Staple foods; (ii) Premium food and drink products; (iii) Trust in reliable sources; (iv) Trust in less reliable sources; and (v) Trust in food vendors. The findings revealed Ghanaian (mean rank = 509.47) and Nigerian (mean rank = 454.82) consumers tended to score higher on the measure of food fraud concern suggesting that they were less confident in the safety and quality of the food they consume. Demographic characteristics including age, number of children, personal and family experience of food fraud and PCA components such as 'Staple foods', 'Trust in reliable sources', and 'Trust in food vendors' significantly predicted the model. This is the first preliminary study to provide empirical findings on consumers' concerns about food fraud in SSA. Practical and policy recommendations for the region are suggested. This includes (i) modelling the AfriFoodinTegrity in West Africa across other major regions such as Central, East, and Southern Africa; (ii) establish a regional sub-Saharan Africa Rapid Alert System for Food and Feed (SSA-RASFF) platform; and (iii) food safety and food fraud reports could be incorporated into SSA-RASFF portal for information sharing.

Environmental exposure assessment of lead and cadmium in street vended foods sold in selected locations in Kenya.

The preparation and handling practices, as well as raw materials for street food vending businesses, could be sources of toxic heavy metals in street vended foods (SVFs). The objective of this study was to assess the levels of lead (Pb) and cadmium (Cd) contamination in ready-to-eat SVFs sold in selected locations within Thika town, Kenya. A total of 199 samples consisting of cereal-based foods, sliced fruits, salads, groundnuts, tubers, fresh fruit juices, eggs, smokies, and sausages were randomly collected for analysis. The concentration of Pb and Cd in street vended foods (SVFs) was determined by atomic absorption spectrophotometry. The results indicated that at least one of the food sample types was contaminated with Pb. The level of Pb contamination in SVFs ranged between 0.271 ± 0.070 and 1.891 ± 0.130 mg/kg with groundnuts recording significantly (p < .0001) higher levels (1.891 mg/kg) than all other food samples. Cadmium contamination levels in the SVF samples ranged between 0.001 ± 0.001 and 0.010 ± 0.003 mg/kg. Significantly (p < .0001) high levels of Cd were observed in cereal-based foods (0.010 mg/kg) and fresh fruit juices (0.008 mg/kg). The Pb concentrations reported in this study are a food safety concern since they exceed the maximum recommended limits set by the Joint Food and Agriculture Organization (FAO)/World Health Organization (WHO) food standards program. There is therefore a need for the establishment and enforcement of policies to govern the street food vending businesses to reduce heavy metal contamination in the SVFs.

Valorization of African indigenous leafy vegetables: The role of phyllosphere microbiota.

In sub-Saharan Africa, malnutrition occurs in various forms going from micronutrient deficiency (MND) to severe malnutrition. In this scenario, African indigenous leafy vegetables (AILVs) could help in alleviating hunger and food insecurity. Principally used by smallholder farmers as subsistence crops thanks to the ease of growing, AILVs have been reported to have valuable nutrient content. Nevertheless, rough handling coupled with microbial activities could lead to phyllosphere deterioration, hence leading to spoilage events that make the sustainable supply and consumption of AILVs difficult. Reviewing the literature regarding AILVs' phyllosphere microbiota, some bacteria such as Pseudomonadaceae, Enterobacteriaceae, and lactic acid bacteria (LAB) were commonly found. Their ability to deteriorate vegetables is known, thus stressing the necessity to valorize these commodities. In this review, fermentation was deepened as an inexpensive form of food processing to valorize AILVs, modulating the phyllosphere microbiota in favor of fermenting microorganisms. The literature review revealed that traditional methods implying alkaline fermentation lower the levels of toxigenic compounds in AILVs such as cyanhydric acid. Methods involving lactic acid bacteria (LAB) fermentation with beneficial LAB were able to control the fermentation, hindering the proliferation of spoilage (i.e. Pseudomonadaceae) and potentially pathogenic bacteria (i.e. Enterobacteriaceae). Aside, the improvement of nutritional content is achieved, obtaining increased levels of B-group vitamins, carotenoids, and the reduction of antinutrient and toxic compounds for certain AILVs. Furthermore, the AILVs' shelf life is also prolonged, thus further confirming that the final products are valorized by the fermentation processes. Howbeit, this review also points out some weaknesses in the methods. Indeed, alkaline fermentation can allow the growth of toxin-producing Bacillus spp. that can jeopardize the consumers' health. While the unpredictability of spontaneous LAB fermentation caused in some cases the resilience of certain pathogens such as Enterobacteriaceae. More studies involving alternative ways to inoculate LAB starters such as back slopping might be useful to perfect the fermentation methods and finally valorize AILVs.

Microbial Contamination and Occurrence of Aflatoxins in Processed Baobab Products in Kenya.

Baobab fruit demand has been on the rise in the recent past, and in an attempt to match the demand, farmers and middlemen are forced to harvest immature fruits which are not fully dried. To ensure an acceptable moisture content, baobab fruits are subjected to solar drying, which is a slow process and often carried out in open and unhygienic conditions raising safety concerns. This study was conducted to investigate the microbial and aflatoxin contamination levels in ready-to-eat baobab products from selected formal and informal processors in specific counties of Kenya. Selected processed baobab products were sampled randomly from formal and informal processors and analyzed for the total aerobic count, Enterobacteriaceae, yeast and molds, ergosterol, aflatoxins, moisture, and water activity. The moisture and water activity of baobab pulp and candies from formal processors ranged between 7.73% and 15.06% and 0.532 and 0.740 compared to those from informal processors which ranged from 10.50% to 23.47% and 0.532 to 0.751, respectively. In this study, baobab pulp from formal processors had significantly (p = 0.0008, 0.0006) lower Enterobacteriaceae and yeast and molds loads (0.7 ± 0.29 and 3.1 ± 0.38 log 10 CFU/g, respectively) than pulp from informal processors (3.1 ± 0.70 and 5.3 ± 0.11 log 10 CFU/g, respectively). Similarly, the Enterobacteriaceae counts of candies from formal processors (nondetectable) were considerably lower (p = 0.015) than those from informal processors (1.8 ± 0.56 log 10 CFU/g). The ergosterol content in these baobab product samples ranged between 0.46 and 1.92 mg/100 g while the aflatoxin content ranged between 3.93 and 11.09 × 103 µg/kg, respectively. Fungal and aflatoxin contamination was detected in 25% and 5% of pulp from formal and informal processors, respectively, and in 5% of candies from informal processors. Microbial contamination in processed baobab products shows an unhygienic processing environment while the fungal and aflatoxin contamination may indicate poor postharvest handling, transport, and storage conditions of baobab fruits along the baobab value chain.

Evolution of microbial communities and nutritional content of fermented Amaranthus sp. leaves.

Amaranth (Amaranthus sp.) is a promising indigenous leafy vegetable plant capable of contributing to food security in sub-Saharan Africa, thanks to its adaptability to diverse soils and its drought tolerance. Its edible parts such as leaves are characterized by high nutrient content. Food losses along the supply chain due to spoilage, however, especially of fresh produce is a challenge facing most of the sub-Saharan African countries in tackling food insecurity in the region. This calls for innovative yet inexpensive solutions such as natural fermentation to preserve the quality and safety of the commodity. To demonstrate the feasibility of natural fermentation in the preservation of vegetable amaranth, leaves were submerged (1:0.5 w/v) in distilled water with 3% sucrose and 3% NaCl dissolved. Control batches were prepared using only distilled water (1:0.5 w/v) with amaranth leaves. Samplings of both treated leaves and controls occurred at 0, 24, 48, 72, and 168 h to measure the pH and determine microbial population changes using culture and molecular-based techniques. Furthermore, the effects of treatment on nutritional content were assayed at the end of the process to determine the levels of B-group vitamins, ß-carotene, lutein, and anti-nutrient phytic acid from unfermented fresh air-dried and 3% sucrose and 3% NaCl treated amaranth leaves. Finally, a visive and olfactive analysis was carried out to evaluate the acceptability of the final product. The significant drop of pH and the correct growth of Lactobacillaceae occurred only in treated batches, although Lactococcus was found in both treated and control samples. Furthermore, mean counts observed on selective media for controls and molecular high-throughput sequencing (HTS) analyses confirmed that in control samples, the undesired bacteria represented more than 60% of the microbial population. In treated amaranth leaves the amount of thiamin, riboflavin, vitamin B6, ß-carotene and lutein content were higher compared to the fresh unfermented air-dried leaves, and phytic acid content diminished after 7-days treatment. These findings suggest that treatment of amaranth leaves using 3% sucrose and 3% NaCl does not only preserve the commodity by arresting the growth of undesired microorganisms involved in spoilage and fosters the lactic acid bacteria but also improves the nutritional content of the fermented end product that has been warmly welcomed by panelists.

In Vitro Study of Cricket Chitosan's Potential as a Prebiotic and a Promoter of Probiotic Microorganisms to Control Pathogenic Bacteria in the Human Gut.

In this study, cricket chitosan was used as a prebiotic. Lactobacillus fermentum, Lactobacillus acidophilus, and Bifidobacterium adolescentis were identified as probiotic bacteria. Cricket chitin was deacetylated to chitosan and added to either De Man Rogosa and Sharpe or Salmonella/Shigella bacterial growth media at the rates of 1%, 5%, 10%, or 20% to obtain chitosan-supplemented media. The growth of the probiotic bacteria was monitored on chitosan-supplemented media after 6, 12, 24, and 48 h upon incubation at 37 °C. Growth of Salmonella typhi in the presence of probiotic bacteria in chitosan-supplemented media was evaluated under similar conditions to those of the growth of probiotic bacteria by measuring growth inhibition zones (in mm) around the bacterial colonies. All chitosan concentrations significantly increased the populations of probiotic bacteria and decreased the populations of pathogenic bacteria. During growth, there was a significant pH change in the media with all probiotic bacteria. Inhibition zones from probiotic bacteria growth supernatant against Salmonella typhi were most apparent at 16 mm and statistically significant in connection with a 10% chitosan concentration. This study suggests cricket-derived chitosan can function as a prebiotic, with an ability to eliminate pathogenic bacteria in the presence of probiotic bacteria.

Fermentation as a tool for increasing food security and nutritional quality of indigenous African leafy vegetables: the case of Cucurbita sp.

Sub-Saharan region is often characterized by food and nutrition insecurity especially "hidden hunger" which results from inadequate micronutrients in diets. African indigenous leafy vegetables (AILVs) can represent a valid food source of micronutrients, but they often go to waste resulting in post-harvest losses. In an attempt to prolong AILVs shelf-life while enhancing their nutritional quality, fermentation was studied from a microbiological and nutritional point of view. Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Controls were set up, consisting of leaves with no additions. During fermentation, samples of both treatments were taken at 0, 24, 48, 72 and 168 h to monitor pH and characterize the microbial population through culture-based and molecular-based analyses. Variations between fresh and treated leaves in B-group vitamins, carotenoids, polyphenols, and phytic acid were evaluated. Data revealed that the treatment with addition of NaCl and sucrose hindered the growth of undesired microorganisms; in controls, unwanted microorganisms dominated the bacterial community until 168 h, while in treated samples Lactobacillaceae predominated. Furthermore, the content in folate, ß-carotene and lutein increased in treated leaves compared to the fresh ones, while phytic acid diminished indicating an amelioration in the nutritional value of the final product. Thus, fermentation could help in preserving Cucurbita sp. leaves, avoiding contamination of spoilage microorganisms and enhancing the nutritional values.

Effects of Traditional Processing Techniques on the Nutritional and Microbiological Quality of Four Edible Insect Species Used for Food and Feed in East Africa.

Edible insects are increasingly being considered as food and feed ingredients because of their rich nutrient content. Already, edible insect farming has taken-off in Africa, but quality and safety concerns call for simple, actionable hazard control mechanisms. We examined the effects of traditional processing techniques-boiling, toasting, solar-drying, oven-drying, boiling + oven-drying, boiling + solar-drying, toasting + oven-drying, toasting + solar-drying-on the proximate composition and microbiological quality of adult Acheta domesticus and Ruspolia differens, the prepupae of Hermetia illucens and 5th instar larvae of Spodoptera littoralis. Boiling, toasting, and drying decreased the dry matter crude fat by 0.8-51% in the order: toasting > boiling > oven-drying > solar-drying, whereas the protein contents increased by 1.2-22% following the same order. Boiling and toasting decreased aerobic mesophilic bacterial populations, lowered Staphylococcus aureus, and eliminated the yeasts and moulds, Lac+ enteric bacteria, and Salmonella. Oven-drying alone marginally lowered bacterial populations as well as yeast and moulds, whereas solar-drying alone had no effect on these parameters. Oven-drying of the boiled or toasted products increased the aerobic mesophilic bacteria counts but the products remained negative on Lac+ enteric bacteria and Salmonella. Traditional processing improves microbial safety but alters the nutritional value. Species- and treatment-specific patterns exist.

Effect of selected pretreatments prior to drying on physical quality attributes of dried mango chips.

This study investigated the effect of pretreatments namely citric acid, lemon juice and blanching on the physical attributes of dried chips from two popular commercial mango varieties grown in Kenya viz 'Apple' and 'Ngowe'. The pretreated mango chips were either subjected to a convective dryer or solar drying. Moisture content, extent of dryness, rehydration characteristics, water activity and color retention were determined to establish the effect of the pretreatments before drying on physical quality attributes of dried mango chips. Moisture content, water activity and color were determined using standard procedures. Equilibrium relative humidity was estimated using Drycard™. Results obtained indicated that optimal drying was achieved with dryer temperatures of 50 °C and 65 °C for 10 and 7 h respectively that reduced moisture content to ~ 11% and water activity to below 0.65 (sufficient for inhibited spoilage). The best color parameters and rehydration characteristics were observed with 1% citric acid and 0.5 v/v lemon acid pretreated samples. Blanched as well as control (untreated) samples showed relatively poor color retention in relation to flesh mango chips and had the least rehydration ratio (1.65 ± 0.01) and coefficient of rehydration (0.33 ± 0.1). As pretreatments before drying affect physical parameters of dried mango chips, the best choice of pretreatments should be made to produce high quality end products. Citric acid and lemon juice pretreatments before drying at 50 °C and 65 °C had the optimal outcome and produced the best physical quality parameters.

The effect of different processing methods on nutrient and isoflavone content of soymilk obtained from six varieties of soybean grown in Rwanda.

Soymilk is rich in nutrients and isoflavones, and could greatly promote nutrition and health. However, this product is not widely accepted due to an objectionable beany flavor. Several methods involving heat treatment and soaking in basic solutions prior to soymilk extraction have been reported to reduce the objectionable flavor. However, the effects of such treatments on the nutritional value and isoflavone content of soymilk, and the responses of different soybean varieties to nutrient extraction by these methods is not well studied. The aim of this study was to determine the effect of three processing methods on protein, fat, minerals, and isoflavone content in soymilk from six soybean varieties grown in Rwanda (Peka-6, SB 24, Sc. Sequel, Sc, Squire, and a local variety) to find the best variety and processing method. The first method (M1) involved soaking soybeans in water for 12 hr prior to milk extraction, M2 involved blanching in NaHCO 3 prior to extraction and M3 involved soaking in NaHCO 3 solution for 16 hr and subsequent cooking prior to extraction. M1 resulted in significantly higher nutrient and isoflavone extraction than M2 and M3. Thus, M1 extracted more nutrients and can be recommended for soymilk production. However, where consumers prefer soymilk obtained by M2 or M3, Sc Squire and the local variety may be recommended. Sc. Squire has another advantage of higher isoflavone content than the other varieties. Further comprehensive studies on the sensory acceptability of products made from different varieties by different methods among different consumer categories will be necessary.

Effects of pretreatment during drying on the antioxidant properties and color of selected tomato varieties.

Drying is essential in lowering the water activity and increasing the shelf stability of perishables. Thus, this study investigated the effect of pretreatment on the retention of the antioxidant properties and color of four tomato varieties; that is, Anna F1, Kilele, Prostar F1, and Riogrande during drying. Prepared quarters were treated by spraying with 0.5% sodium metabisulfate, 0.5% calcium chloride, and distilled water. The quarters were oven dried at 50°C, 60°C, and 70°C to 13% moisture content. Lycopene, ß carotene, total phenolics, color, and moisture content were determined in both the fresh and dried samples. Initial moisture content among the four varieties did not differ significantly and ranged between 94.2 and 94.6%. Results showed that the main effects were significant (p < .05) on all measurable variables. Significantly (p < .05) higher retention levels in lycopene, ß carotene, total phenolics, and lightness was observed in chemically pretreated samples compared to the control during drying.

Influence of physicochemical parameters on storage stability: Microbiological quality of fresh unpasteurized fruit juices.

Fresh juices rich in health and nutritional benefits are valued for their fresh flavor, taste, and aroma. These juices' quality however is affected by factors like temperature, light, and microbiological contamination significantly changing physicochemical parameters and storage stability. Physicochemical and microbiological analyses of passion fruit, pineapple, and mango juices in dark and light bottles at 24°C and 4°C were conducted in Kampala, Uganda for 12 days. Physicochemical parameters significantly reduced (p < .05) storage stability of fresh juices, while no significant changes (p > .05) were observed for the microbiological analyses. pH values ranged from 3.0 to 4.2 (dark) bottles and 2.9 to 4.0 (light) bottles for juices at 24°C and 4°C. °Brix values were from 1.0 to 5.5 for dark and clear bottles at 24°C and 4°C. TTA (%) values ranged from 1.1 to 7.2 (dark) bottles and 1.1 to 7.4 for (light) bottles at 24°C and 4°C. Ascorbic acid content ranged from 3.5 to 61.0 mg/ 100 ml and 5.5 to 56.7 mg/100 ml for juices in dark and clear bottles, respectively. total plate counts ranged from 1.3 × 10___ to 3.3 × 107 CFU/ml (dark bottles at 24°C) to 3.5 × 10³ to 3.3 × 108 CFU/ml (dark bottles at 4°C). For juices in light bottles, total plate counts ranged from 1.8 × 10___ to 8.0 × 107 CFU/ml (24°C) and 2.7 × 10___ to 1.5 × 108 CFU/ml (4°C). High microbial loads suggest the use of poor processing techniques and lack of good hygiene which lower quality and reduce storage stability of juices. Storage temperature greatly reduces physicochemical parameters both at ambient and refrigeration temperatures. This implies that temperature control for unpasteurized juices is critical in order to inhibit microorganism metabolic activities which accelerate biodeterioration leading to spoilage and short shelf life. Fresh unpasteurized juices stored at 24°C and 4°C may safely be consumed within 1 and 2 days, respectively.

Evaluation of the proximate composition, antioxidant potential, and antimicrobial activity of mango seed kernel extracts.

After pulp extraction in fruit processing industry, a significant quantity of mango seed kernels are discarded as solid wastes. These seed kernels can be ideal raw materials for obtaining extracts rich in bioactive compounds with good antioxidant properties. The conversion of these wastes into utilizable food ingredients would help in reducing environmental problems associated with processing waste disposal. In order to determine their potential use, this study evaluated some of the biochemical characteristics and antimicrobial potential of mango seed kernel extracts on medically important human bacterial and fungal pathogens. Four mango varieties (Apple, Ngowe, Kent and Sabine) from Makueni and Embu counties in Kenya were used for this study. The analyzed mango seed kernel powders were found to contain on average, 6.74-9.20% protein content. Apple and Ngowe mango seed kernels had significantly higher fat content of 13.04 and 13.08, respectively, while Sabine from Makueni had the least fat content of 9.84%. The ash, fiber, and carbohydrate contents ranged from 1.78 to 2.87%, 2.64 to 3.71% and 72.86 to 75.92%, respectively. The mean percentage scavenging ability of mango kernel extracts at the concentration of 20 mg/mL was 92.22%. Apple and Sabine mango kernel extracts had significantly high inhibition zones of 1.93 and 1.73 compared to Kent and Ngowe with 1.13 and 1.10, respectively, against E. coli. For C. albicans, the inhibition of Kent mango kernel extract, 1.63, was significantly lower than that of Ngowe, Apple, and Sabine with 2.23, 2.13, and 1.83, respectively. This study demonstrates that mango seed powder is an abundant and cost-effective potential natural antibiotic and antifungal that can be utilized in addressing the challenge of food poisoning and infections caused by pathogenic microorganisms in the food industry.

Molecular studies to identify the Fusarium species responsible for HT-2 and T-2 mycotoxins in UK oats.

High levels of Fusarium mycotoxins HT-2 and T-2 have been detected in UK oats since surveys started in 2002. Fusarium langsethiae and the closely related species F. sporotrichioides have previously been associated with the contamination of cereals with type A trichothecenes HT-2 and T-2 in Nordic countries. Preliminary microbiological analysis of UK oat samples with high concentrations of HT-2 and T-2 detected and isolated F. langsethiae and F. poae but not the other type A trichothecene producing species F. sporotrichioides, F. sibiricum and F. armeniacum. Two hundred and forty oat flour samples with a known mycotoxin profile were selected from a previous four year study (2002-2005) to cover the full concentration range from below the limit of quantification (<20 µg/kg) to 9,990 µg/kg HT-2+T-2 combined. All samples were analysed for the DNA of F. langsethiae, F. poae and F. sporotrichioides based on previously published PCR assays. F. langsethiae was detectable in nearly all samples; F. poae was detected in 90% of samples whereas F. sporotrichioides was not detected in any sample. A real-time PCR assay was developed to quantify F. langsethiae DNA in plant material. The assay could quantify as low as 10(-4)ngF. langsethiae DNA/µl. Based on this assay and a previously published assay for F. poae, both species were quantified in the oat flour samples with known HT-2+T-2 content. Results showed a good regression (P<0.001, r(2)=0.60) between F. langsethiae DNA and HT-2+T-2 concentration. F. poae DNA concentration was not correlated to HT2+T2 concentration (P=0.448) but was weakly correlated to nivalenol concentration (P<0.001, r(2)=0.09). Multiple regression with F. langsethiae and F. poae DNA as explanatory variates identified that both F. langsethiae and F. poae DNA were highly significant (P<0.001) but F. poae DNA only accounted for an additional 4% of the variance and the estimate was negative, indicating that higher concentrations of F. poae DNA were correlated with slightly lower concentrations of HT2+T2 detected. A stronger regression (P<0.001, r(2)=0.77) between F. langsethiae DNA and HT-2+T-2 was obtained after extraction and quantification of DNA and mycotoxins from individual oat grains. The results from this study provide strong evidence that F. langsethiae is the primary, if not sole, fungus responsible for high HT-2 and T-2 in UK oats.