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.

Safety evaluation of the food enzyme glucan 1,4-α-maltohydrolase from the genetically modified Bacillus licheniformis strain NZYM-FR.

The food enzyme glucan 1,4-α-maltohydrolase (4-α-d-glucan α-maltohydrolase; 3.2.1.133) is produced with the genetically modified Bacillus licheniformis strain NZYM-FR by Novozymes A/S. The genetic modifications did not give rise to safety concerns. The production strain has been shown to qualify for Qualified Presumption of Safety (QPS) status. The food enzyme is free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in three food manufacturing processes, namely baking and brewing processes and starch processing for glucose syrup production and other starch hydrolysates. Since residual amounts of total organic solids (TOS) are removed by the purification steps applied during the production of glucose syrups, dietary exposure was calculated only for the baking and brewing processes. Dietary exposure was estimated to be up to 0.30 mg TOS/kg body weight (bw) per day in European populations. Given the QPS status of the production strain and the lack of hazards resulting from the food enzyme manufacturing process, toxicological studies were not considered necessary. Similarity of the amino acid sequence to those of known allergens was searched and four matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood of such reactions to occur is considered to be low. Based on the data provided, the QPS status of the production strain and the absence of issues arising from the production process, the Panel concluded that the food enzyme glucan 1,4-α-maltohydrolase produced with the genetically modified B. licheniformis strain NZYM-FR does not give rise to safety concerns under the intended conditions of use.

Anaerobic digestion and aerobic composting of rigid biopolymers in bio-waste treatment: fate and effects on the final compost.

Bioplastics may be collected in the bio-waste treatment, which is often composed of anaerobic digestion and subsequent aerobic composting of the digestates. The aim of this study was to evaluate the degradability of polylactic acid (PLA) and starch-based bioplastics (SBB) spoons under industrial conditions. Biomethane potential (BMP) was measured and biogas production was monitored, while the quality of composts was assessed by phytotoxicity and ecotoxicity tests. The bioplastics disintegration resulted in 65.1 ± 4.6 % for PLA and ≤ 65.0 ± 7.4 % for SBB, not achieving the target set by UNI EN 13,432 standard, and several residues were found in compost. Phytotoxicity tests on seeds reported the lowest Germination Index for PLA elutriate, whereas a potential negative effect of SBB on soil fauna was detected. Further investigation is needed to assess the fate of these ever-growing materials under industrial conditions, and also evaluate the effects of residues in compost.

Safety evaluation of the food enzyme containing chymosin and pepsin from the abomasum of suckling lambs.

The food enzyme rennet containing chymosin (EC 3.4.23.4) and pepsin (EC 3.4.23.1) is prepared from the abomasum (stomach) of suckling lambs, by Productos Nievi, SA. The food enzyme is intended to be used in milk processing for cheese production. As no concerns arise from the animal source of the food enzyme, from its manufacture, and based on the history of safe use and consumption, the Panel considered that toxicological data were not required and no exposure assessment was necessary. On the basis of literature data, the Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure could not be excluded, but the likelihood for this to occur was considered to be low. Based on the data provided, the Panel concludes that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Monitoring the bacterial population dynamics during fermentation of artisanal Argentinean sausages.

The dynamics of the microbial community responsible for the artisanal fermentation of dry sausage produced in Argentina was investigated by using classical and molecular approaches. The combined use of RAPD analysis with primers M13, XD9, RAPD1 and RAPD2 and 16S rDNA sequencing were applied to the identification and intraspecific differentiation of 100 strains of lactobacilli and Micrococcaceae. DGGE analysis was used to monitor the dynamic changes in population after total microbial DNA was directly extracted from sausages and subjected to PCR using V3f (GC), Bact-0124f-GC and Univ-0515r primers. The sequence analysis of 16S rDNA of the dominant species was also carried out. Lactobacillus sakei and Lactobacillus plantarum were the dominant lactic acid organisms during the fermentation while Staphylococcus saprophyticus represented the dominant species of Micrococcaceae. It was demonstrated that the ripening process of Argentinean artisanal fermented sausage is driven by a limited number of Lactobacillus and Staphylococcus strains selected from environmental microbiota by the ability to best compete under the prevailing conditions of the ecological niche. The identification of dominant communities present in this artisanal fermented sausage can help in the selection of starter cultures consisting in well adapted strains to the particular production technology.