Use of natural plant extracts as a novel microbiological quality indicator in raw milk: An alternative for resazurin dye reduction method

In the present study, we propose a novel field-scale analytical tool for rapid screening of microbiological quality in raw milk using aqueous extracts of plant materials, i.e. flowers (e.g. Hibiscus rosa-sinensis L. and Clitoria ternatea), taproots (e.g. Beta vulgaris) and pricklypears (e.g. Opuntia dillenii). For each plant extract, the colour changes in raw milk were evaluated between 4.5 and 6.5 pH against the resazurin dye as a control. The plant anthocyanin content in each extract was analyzed by the differential pH method using a spectrophotometer. The Hibiscus rosa-sinensis flower extract was opted to further test since it had a pH-sensitive colour change (6.5; maroon to 6.2; light-pink) compared to other plant extracts, which did not indicate a noticeable colour variation with pH. Anthocyanin content of the Hibiscus extract was 0.59 g/mL. The novel method showed high linearity (R-2 = 0.95), 100% accuracy and greater repeatability with an intermediate level of precision. The limit of quantification and detection was 0.46 and 0.15 g/mL, respectively. In conclusion, we demonstrated the potential in using water extract of Hibiscus rosa-sinensis L. flowers as an alternative to the resazurin dye reduction method for rapid and accurate microbiological quality control for raw milk procurement in remote areas

Inclusion of Probiotics into Fermented Buffalo (Bubalus bubalis) Milk: An Overview of Challenges and Opportunities

Buffalo-milk-based dairy products provide various health benefits to humans since buffalo milk serves as a rich source of protein, fat, lactose, calcium, iron, phosphorus, vitamin A and natural antioxidants. Dairy products such as Meekiri, Dadih, Dadi and Lassie, which are derived from Artisanal fermentation of buffalo milk, have been consumed for many years. Probiotic potentials of indigenous microflora in fermented buffalo milk have been well documented. Incorporation of certain probiotics into the buffalo-milk-based dairy products conferred vital health benefits to the consumers, although is not a common practice. However, several challenges are associated with incorporating probiotics into buffalo-milk-based dairy products. The viability of probiotic bacteria can be reduced due to processing and environmental stress during storage. Further, incompatibility of probiotics with traditional starter cultures and high acidity of fermented dairy products may lead to poor viability of probiotics. The weak acidifying performance of probiotics may affect the organoleptic quality of fermented dairy products. Besides these challenges, several innovative technologies such as the use of microencapsulated probiotics, ultrasonication, the inclusion of prebiotics, use of appropriate packaging and optimal storage conditions have been reported, promising stability and viability of probiotics in buffalo-milk-based fermented dairy products

Milk Coagulation Properties - A Study on Milk Protein Profile of Native and Improved Cattle Breeds Types in Sri Lanka

This study was conducted to assess the variations of milk coagulation properties (MCP) among two native cattle types, e.g., Thamankaduwa White (TW), Lankan cattle (LC) and two improved cattle breeds, e.g., Friesian (FR) and Jersey (JS), in relation to distinctive milk protein compositions. MCP traits, including rennet coagulation time (RCT), curd firmness, meltability and yield, were measured. The milk protein profile of each breed/type was analyzed using capillary zone electrophoresis. Significant differences (

Probiotics and Beneficial Microorganisms in Biopreservation of Plant-Based Foods and Beverages

Maintaining the overall quality and shelf life of plant-based food and beverages is particularly important yet challenging to the food industry. Demand for natural preservation techniques has increased with the rising concerns over food safety and consumer awareness, e.g., health consciousness and food trends such as veganism and the demand for clean, labelled foods. Thus, a technique such as biopreservation has the potential to enhance food safety while fostering the quality, originality and naturalness of food. The application of probiotic microorganisms to foods and beverages provides various health benefits in addition to improved shelf life, stability and microbial safety of the food. The provision of probiotics is known to deliver various health benefits for the host’s gut health. Therefore, this review aims to investigate the importance of biopreservation and the role of probiotics in the food industry. An attempt was made to explore the various possibilities of shelf-life enhancement through the use of probiotic microorganisms as biopreservatives. Noticeable improvements in the shelf life of plant-based foods and beverages were observed due to the antimicrobial effects exerted by probiotics and potential probiotic strains which make them useful alternatives to artificially synthesized chemical preservatives

Effects of ultrasound on the fermentation profile of fermented milk products incorporated with lactic acid bacteria

Ultrasonic processing of fermented milk products has created much interest in current research on dairy products. This has been employed in cultured milk products to enhance the emulsification of milk fat and to intensify the fermentation process. Benefits including remarkable product stability, reduced processing time and enhanced quality are being recorded. Ultrasound (US) altered the colour and flavour profile of milk; however, the effect of US-induced fermentation on the synthesis of flavour compounds in milk has not been reported in the literature. This review paper presents a comprehensive scenario on the impact of power US on the fermentation profile and quality of ultrasonically processed dairy products. A theoretical background on US and details of its effect on the metabolic performance of lactic acid bacteria are presented. Finally, it describes how the quality attributes of fermented milk gels are modified due to the intensification of the fermentation process with US

Traditional Sri Lankan fermented buffalo (Bubalus bubalis) milk gel (Meekiri): technology, microbiology and quality characteristics

Meekiri (sometimes also known as Mee-Deekiri); fermented buffalo milk gel is a deep-rooted dairy product in Sri Lankan food culture and the production of Meekiri plays an integral part in the livelihood of rural farming. Meekiri consumption is widespread irrespective of geographic boundaries, across the cultural and/or ethnic communities. In Sri Lanka, buffalo milk is predominantly used in producing Meekiri, where production has been specialized in various geographic areas in the country, associated with major buffalo farming regions. Physicochemical and microbiological quality attributes are apparent to differ in Meekiri according to varying production regions, processing techniques and storage conditions. The mouthfeel and taste of Meekiri are widely accepted to be thicker and creamier with a pleasant note and is whiter in colour compared to fermented cow milk gel/yoghurt. Since Meekiri production is localized in Sri Lanka and available as traditional know-how at the primary production level, up-to-date comprehensive scientific literature that accounts for processing and detailed product quality characteristics is lacking. Hence, this review evaluates and outlines updated information about the Meekiri production, associated buffalo farming systems, quality characteristics of Meekiri including physicochemical, sensorial and microbiological aspects in the final product