Microbiological assessment of ready-to-eat foods and drinking water sources as a potential vehicle of bacterial pathogens in northern India.

Foodborne illnesses caused by the consumption of contaminated foods have frequent occurrences in developing countries. The incorporation of contaminated water in food processes, preparation, and serving is directly linked to several gastrointestinal infections. Keeping in view, this study was conducted to assess the microbial quality of both drinking water sources and commonly consumed fresh ready-to-eat (RTE) foods in the region. The drinking water samples from water sources and consumer points, as well as food samples from canteens, cafes, hotels, and restaurants, were collected for the microbiological analysis. Fifty-five percent (n = 286) of water samples were found to be positive for total coliforms with MPN counts ranging from 3 to 2600 (100 ml) -1. E. coli was detected in nearly 30% of the total water samples. Overall, 65% tap water samples were found unsatisfactory, followed by submersible (53%), filter (40%), and WTP (30%) sources. Furthermore, the examination of RTE foods (n = 80) found that 60% were of unsatisfactory microbial quality with high aerobic plate counts. The salads were the most contaminated category with highest mean APC 8.3 log CFU/g followed by pani puri, chats, and chutneys. Presence of coliforms and common enteropathogens was observed in both water and food samples. The detected isolates from the samples were identified as Enterobacter spp., Klebsiella spp., Pseudomonas aeruginosa, Salmonella spp., Shigella spp., and Staphylococcus spp. Based on these findings, microbiological quality was found compromised and this may pose hazard to public health. This exploratory study in the Punjab region also suggests that poor microbiological quality of water sources can be an important source of contamination for fresh uncooked RTE foods, thus transferring pathogens to the food chain. Therefore, only safe potable drinking water post-treatment should be used at all stages.

Development and standardization of processing technique for ready-to-use lab fermented Kanji mix using refractance window dried black carrot powder.

Black carrots are rich in bio-actives but underutilized owing to their short-term availability and perishable nature. Traditionally, black carrots have been used for the preparation of Kanji-a fermented non-dairy beverage prepared using natural fermentation by lactic acid bacteria and a few spices. This plant-based probiotic beverage has high antioxidant properties but there is a risk of contamination with pathogens due to uncontrolled fermentation during storage. To enhance the availability of this nutritious beverage throughout the year and to ensure the microbiological safety of the traditional fermented product, the present study was planned to optimize the process for controlled fermentation using freeze-dried lactic acid bacterial (LAB) culture and refractance window-dried black carrot powder. The physicochemical and microbiological profiles of LAB-fermented Kanji were analysed. The dried Kanji mix can be reconstituted into naturally fermented probiotic beverage with unique flavour and aroma along with ensured microbiological safety and enhanced commercial value.

Physicochemical and microbiological evaluation of antioxidant-rich traditional black carrot beverage: Kanji.

BACKGROUND: Daucus carota subsp. sativus (Black carrots) are underutilized in context to their nutritional properties. In this study, Kanji, a naturally fermented probiotic beverage, was prepared using Daucus carota subsp. sativus (var. Punjab Black Beauty). Analysis of the physicochemical and microbiological profile of the naturally fermented Kanji was investigated to boost its utilization for commercial purpose. RESULTS: The physicochemical parameters observed in the fermented Kanji beverage were pH 3.47, total soluble solids 3°B, lactic acid 0.99%, total sugars 36.32 mg/mL, total reducing sugars 27.16 mg/mL, flavonoids 38.14 mg/mL, phenols 40.8 mg/mL, antioxidant activity 79.96% and ascorbic acid 110 mg/100 mL. The microbiological analysis revealed an exponential increase in lactic acid bacterial count from 3.96 to 8.33 log CFU/mL. Out of 11 bacterial strains isolated from Kanji, the bacterial strain with high growth potential was genotypically characterized as Pediococcus acidilactici with accession number MK028218. CONCLUSION: The lactic acid bacterial Kanji beverage was characterized as a potential plant-based probiotic with high antioxidant activity. This functional autochthonous starter from the Kanji can be used for selective fermentation of black carrots for Kanji ascertaining its microbiological safety, unique flavor and aroma, and consumption as a commercial non-dairy-based probiotic beverage.

Antioxidant Potential, Antinutrients, Mineral Composition and FTIR Spectra of Legumes Fermented with Rhizopus oligosporus.

RESEARCH BACKGROUND: Legumes are superior sources of macro- and micronutrients which can be further enhanced by fermentation. This can assist in addressing the food security concerns. The present study aims to determine the effect of fermentation by Rhizopus oligosporus on nutritional and antinutritional composition of some commonly consumed legumes. EXPERIMENTAL APPROACH: Chickpea (kabuli and desi), pigeon pea and soybean were fermented with Rhizopus oligosporus (at 34 °C for 52 h), dried at 45 °C for 16-18 h and milled. Antioxidant potential, phenolic composition, antinutrients, mineral composition and FTIR spectra of fermented and unfermented flour samples were evaluated. RESULTS AND CONCLUSIONS: Fermentation significantly (p<0.05) enhanced the total phenolic and flavonoid contents, and antioxidant properties (radical scavenging activity, reducing power, ferric reducing antioxidant power and metal chelation) of kabuli and desi chickpeas, and soybean. Although fermented pigeon pea exhibited excellent antioxidant properties, the effect of fermentation on such properties was either minimal or insignificant. Additionally, quantification of specific phenolics using HPLC showed higher mass fractions of certain compounds such as chlorogenic, p-hydroxybenzoic, gallic and vanillic acids in fermented legumes. Mass fraction of phytic acid in all the fermented legumes was reduced (p<0.05), while trypsin inhibition increased (p<0.05). In kabuli and desi chickpeas, and pigeon pea, saponin mass fraction increased (p<0.05) while it decreased in soybean. Tannin mass fraction increased (p<0.05) in desi chickpea, pigeon pea and soybean and decreased (p<0.05) in kabuli chickpea. Furthermore, fermentation enhanced the content and estimated bioavailability of minerals. FTIR spectrum of fermented and unfermented legumes showed the presence of several functional groups and modifications in the molecular structure after fermentation. NOVELTY AND SCIENTIFIC CONTRIBUTION: To our knowledge, this is the first study where legume (kabuli and desi chickpeas, pigeon pea and soybean) fermentation by Rhizopus oligosporus has been assessed for nutritional and antinutritional profile and FTIR spectra. We concluded that the treatment resulted in an optimal balance of nutrients and antinutrients. The process proved to be a potential tool for tackling the concerns of nutritional security, and thus can be proposed for the development of novel legume-based functional foods.

Evaluation and characterization of new α-L-rhamnosidase-producing yeast strains.

A total of thirty yeast strains were isolated from a whey beverage and screened for α-L-rhamnosidase enzyme production. Of these, only four isolates were capable of producing the α-L-rhamnosidase enzyme by hydrolyzing naringin. Scanning electron microscopy images showed that the morphology of the yeast isolate (isolate No. 84) producing the greatest enzyme, changed from oval to filamentous in the presence of naringin. On the basis of morphological and molecular characterization (ITS sequencing), these four isolates were identified as Clavispora lusitaniae-84, Clavispora lusitaniae-B82, Candida sp.-86 and Candida hyderabadensis-S82). Fermentation parameters and the biochemical characterization of the α-L-rhamnosidase-producing yeast isolates were studied based on carbon substrate utilization profiles using BIOLOG phenotype microarray plates. Intra-species genetic diversity among the isolates was evaluated by whole genome analysis with repetitive DNA sequences (ERIC, REP and BOX) based DNA fingerprinting. On the basis of these results, it was found that these isolates of yeast producing L-rhamnosidase have a great potential application for beverage quality enhancement, and can build a strong foundation of α-L-rhamnosidase-producing yeast strains in the debittering of citrus juice.