COMPARATIVE ASSESSMENT OF STORAGE STABILITY OF GINGER-GARLIC AND CHEMICAL PRESERVATION ON FRUIT JUICE BLENDS

The study aimed at reduction of wastage of fruit, encourage production, consumption and preservation of fruit juice blends using garlic ginger filtrate with health benefits as biopreservative thus providing alternatives with biological advantage over chemical preservatives (ascorbic and benzoate acids) without altering the organoleptic and physicochemical properties of fruit juice blends. The study evaluated the potential of natural preservatives (ginger, garlic and ginger-garlic filtrates) in comparison with two conventional chemical preservatives (ascorbic and benzoate acids) for fruit juice blends preservation. The juice blend used was cashew, pineapple and watermelon. In terms of flavor and mouth feel, the order of preference of the juice were the preserved with 1% garlic-ginger > 1% ginger > 1% garlic > 1% ascorbic acid > and preserved with 1% sodium benzoate at ambient temperature. Maximum decrease in pH was observed in the juice sample that had no added preservative. Generally, all the fruit blends (preserved and unpreserved), with the exception of the one preserve with 1% ginger-garlic showed growth of bacteria after one week of storage. Juice blends preserved with the 1% ginger-garlic were most acceptable compared to other preservatives. The synergistic biopreservative ability observed with the ginger-garlic may be a preferable alternative to conventional preservatives

Development of a heptaplex PCR assay for identification of Staphylococcus aureus and CoNS with simultaneous detection of virulence and antibiotic resistance genes

Background Staphylococcal toxicity and antibiotic resistance (STAAR) have been menacing public health. Although vancomycin-resistant Staphylococcus aureus (VRSA) is currently not as widespread as methicillin-resistant S. aureus (MRSA), genome evolution of MRSA into VRSA, including strains engineered within the same patient under anti-staphylococcal therapy, may build up to future public health concern. To further complicate diagnosis, infection control and anti-microbial chemotherapy, non-sterile sites such as the nares and the skin could contain both S. aureus and coagulase-negative staphylococci (CoNS), either of which could harbour mecA the gene driving staphylococcal methicillin-resistance and required for MRSA-VRSA evolution. Results A new heptaplex PCR assay has been developed which simultaneously detects seven markers for: i) eubacteria (16S rRNA), ii) Staphylococcus genus (tuf), iii) Staphylococcus aureus (spa), iv) CoNS (cns), v) Panton-Valentine leukocidin (pvl), vi) methicillin resistance (mecA), and vii) vancomycin resistance (vanA). Following successful validation using 255 reference bacterial strains, applicability to analyse clinical samples was evaluated by direct amplification in spiked blood cultures (n = 89) which returned 100 % specificity, negative and positive predictive values. The new assay has LoD of 1.0x103 CFU/mL for the 16S rRNA marker and 1.0x104 CFU/mL for six other markers and completes cycling in less than one hour. Conclusion The speed, sensitivity (100 %), NPV (100 %) and PPV (100 %) suggest the new heptaplex PCR assay could be easily integrated into a routine diagnostic microbiology workflow. Detection of the cns marker allows for unique identification of CoNS in mono-microbial and in poly-microbial samples containing mixtures of CoNS and S. aureus without recourse to the conventional elimination approach which is ambiguous. In addition to the SA-CoNS differential diagnostic essence of the new assay, inclusion of vanA primers will allow microbiology laboratories to stay ahead of the emerging MRSA-VRSA evolution. To the best of our knowledge, the new heptaplex PCR assay is the most multiplexed among similar PCR-based assays for simultaneous detection of STAAR