Fatty acid-modified chitosan and nanoencapsulation of essential oils: A snapshot of applications.

Chitosan (CS) and its modification with fatty acid (FA) in addition to the nanoencapsulation with essential oils (EOs) have emerged as promising approaches with diverse applications, particularly in food and fruit preservation. This review aims to curate data on the prospects of CS modified with FA as nanostructures, serving as carriers for EOs and its application in the preservation of fruits. A narrative review with no restricted period was used for the general overview of CS and strategies for its modification with FA. Report on CS modified with FA and nanoencapsulation with EO and their applications were appraised. The prospects of CS modified with FA and EO nanoencapsulation in food and fruit preservation were outlined. Most chitosan-fatty acid (CS-FA) studies have found relevance in water, medical and pharmaceutical industries, with few studies on food preservation. CS-FA formulation with EOs shows substantial potential in preserving fruits and will significantly impact the food industry in the future by extending the shelf life of fruits and reducing food waste.

Characterization of Microbial Diversity of Two Tomato Cultivars through Targeted Next-Generation Sequencing 16S rRNA and ITS Techniques.

Even though the nutritional and economic values of Solanum lycopersicum (tomato) are substantially impacted by microbial spoilage, the available data on its microbial community, particularly during spoilage, are limited and have primarily been characterized using conventional culture-dependent methods. This study employed a targeted high-throughput next-generation sequencing method to longitudinally characterize the microbial diversity of two South African tomato cultivars (jam and round) at varied storage intervals (1, 6, and 12 days). Throughout the storage period, the bacterial communities of the two cultivars were more diverse than the fungal communities. The microbial diversity of both bacteria and fungi was greater and comparable between the cultivars on day 1, but becomes distinct as the storage period increases, with round tomatoes being more diverse than jam tomato, though, on day 12, jam tomato develops greater diversity than round tomato. Overall, the most abundant phyla (though Proteobacteria was most dominant) were Proteobacteria, Firmicutes, and Bacteriodota in the bacterial communities, while Ascomycota and Basidiomycota formed most fungal communities with Ascomycota being dominant. At the genus level, Pantoea and Klebsiella (bacteria), Hanseniaspora, Stemphylium, and Alternaria (fungi) were prevalent. Taken together, this study casts light on a broad microbial diversity profile thus, confirms the cultivars' diversity and abundance differences.

Bacterial biofilm formation on stainless steel in the food processing environment and its health implications.

Biofilm formation (BF) and production in the food processing industry (FPI) is a continual threat to food safety and quality. Various bacterial pathogens possess the ability to adhere and produce biofilms on stainless steel (SS) in the FPI due to flagella, curli, pili, fimbrial adhesins, extra polymeric substances, and surface proteins. The facilitating environmental conditions (temperature, pressure, variations in climatic conditions), SS properties (surface energy, hydrophobicity, surface roughness, topography), type of raw food materials, pre-processing, and processing conditions play a significant role in the enhancement of bacterial adhesion and favorable condition for BF. Furthermore, biofilm formers can tolerate different sanitizers and cleaning agents due to the constituents, concentration, contact time, bacterial cluster distribution, and composition of bacteria within the biofilm. Also, bacterial biofilms' ability to produce various endotoxins and exotoxins when consumed cause food infections and intoxications with serious health implications. It is thus crucial to understand BF's repercussions and develop effective interventions against these phenomena that make persistent pathogens difficult to remove in the food processing environment.

Effects of pectin and emulsifiers on the physical and nutritional qualities and consumer acceptability of wheat composite dough and bread.

Rheological behaviour and certain quality attributes of the dough and bread prepared from the wheat-millet-Bambara flour (WMB) containing mixtures of emulsifiers and/or apple pectin were investigated. WMB was prepared by substituting wheat flour (WF) with 25% millet flour and 25% Bambara flour. Pectin (1.0-2.0 g) and emulsifiers namely sodium stearoyl lactylate (0.25-0.40 g), polysorbate 80 (0.50-0.80 g), and diacetyl tartaric acid ester of monoglycerides (0.10-0.25 g) mixed in different proportions were added to produce dough and bread. Mixolab was utilised to measure the rheological behaviour of dough and bread made from all mixes were analysed for physical characteristics, nutritional composition, and organoleptic properties. A significant increase in dough development time (emulsifier: 65% and pectin: 57.9%) and dough stability (emulsifier: 18.2% and pectin: 35.2%) were observed. Loaf volume, specific volume and proximate composition of the composite bread increased significantly relative to control. Protein content (33%), protein digestibility (85%) and certain essential amino acids (lysine: 54.6%; threonine: 36.4%) increased significantly in the WMB bread compared to the WF bread. Sensory evaluation revealed an above average acceptability for the composite bread samples. Emulsifiers and pectin used in the present study resulted in significant improvement in the dough rheology, as well as in the physical characteristics, the nutritional and sensory attributes of the WMB composite bread. The results of the present study confirm the potential for supplementation and fortification of wheat bread using flours from millet and Bambara sources.

Food safety knowledge and microbiological hygiene of households in selected areas of Kwa-Zulu Natal, South Africa.

This study was conducted to determine the level of food safety knowledge and practices during food handling and preparation at household level in selected areas in KwaZulu-Natal province of South Africa. Fifty households were selected to participate based on their monthly income, age and educational level. Samples of raw foods were randomly collected from the participating households for microbial analyses. Swabs from food contact surfaces were also collected and analyzed for the presence of pathogens. Difference in demographic data regarding food safety knowledge was tested using chi-square and microbial counts were statistically analyzed (P<0.05). Knowledge of proper cold storage temperature was found to be inadequate as over 70% of respondents had no idea of their cold storage temperatures. High risk of cross contamination was observed due to improper thawing, packaging of meat with other ready to eat foods and poor food contact material handling. Microbial analyses of raw food samples showed the presence of aerobic spore formers (1.08-1.89 log cfu/mL), anaerobic spore formers (0.29-1.83 log cfu/mL) and Staphylococcus aureus (3.31-3.96 log cfu/mL). Contact surfaces were also positive for Listeria monocytogenes, Salmonella spp and Escherichia coli. Food safety knowledge and proper food handling practices were found to be inadequate in the areas studied and urgent intervention is required to prevent fatal incidences of food borne illnesses.

Inactivation of Heat Adapted and Chlorine Adapted Listeria Monocytogenes ATCC 7644 on Tomatoes Using Sodium Dodecyl Sulphate, Levulinic Acid and Sodium Hypochlorite Solution.

The effectiveness of sodium dodecyl sulphate (SDS), sodium hypochlorite solution and levulinic acid in reducing the survival of heat adapted and chlorine adapted Listeria monocytogenes ATCC 7644 was evaluated. The results against heat adapted L. monocytognes revealed that sodium hypochlorite solution was the least effective, achieving log reduction of 2.75, 2.94 and 3.97 log colony forming unit (CFU)/mL for 1, 3 and 5 minutes, respectively. SDS was able to achieve 8 log reduction for both heat adapted and chlorine adapted bacteria. When used against chlorine adapted L. monocytogenes sodium hypochlorite solution achieved log reduction of 2.76, 2.93 and 3.65 log CFU/mL for 1, 3 and 5 minutes, respectively. Using levulinic acid on heat adapted bacteria achieved log reduction of 3.07, 2.78 and 4.97 log CFU/mL for 1, 3, 5 minutes, respectively. On chlorine adapted bacteria levulinic acid achieved log reduction of 2.77, 3.07 and 5.21 log CFU/mL for 1, 3 and 5 minutes, respectively. Using a mixture of 0.05% SDS and 0.5% levulinic acid on heat adapted bacteria achieved log reduction of 3.13, 3.32 and 4.79 log CFU/mL for 1, 3 and 5 minutes while on chlorine adapted bacteria it achieved 3.20, 3.33 and 5.66 log CFU/mL, respectively. Increasing contact time also increased log reduction for both test pathogens. A storage period of up to 72 hours resulted in progressive log reduction for both test pathogens. Results also revealed that there was a significant difference (P≤0.05) among contact times, storage times and sanitizers. Findings from this study can be used to select suitable sanitizers and contact times for heat and chlorine adapted L. monocytogenes in the fresh produce industry.

Biocontrol of Listeria monocytogenes ATCC 7644 on fresh-cut tomato (Lycopersicon esculentum) using nisin combined with organic acids.

The biocontrol of Listeria monocytogenes on fresh-cut tomato using nisin and organic acids was investigated. Fresh-cut samples inoculated with 108 CFU/mL of L. monocytogenes, treated with nisin (5,000 IU/mL), a combination of nisin and organic acids (acetic and citric acids at 3 and 5% each), with chlorine at 200 ppm as a control, and stored for six days at 4, 10, and 25°C were used to evaluate certain physicochemical qualities (pH, titratable acidity, soluble solid content, vitamin C content, and color). Nisin treatment significantly (p<0.05) reduced bacterial population by 1.91-3.07 log CFU/mL. Nisin-citric acid combination provided 2.65-3.29 log CFU/mL reduction, while nisin-acetic acid combination provided 2.93-4.15 log CFU/mL reduction. The control treatment provided <1-2 fold log reductions. Slight variations in physicochemical properties of fresh-cut tomato were observed. Nisin and organic acids can be used to improve the microbial safety of fresh-cut tomato.