ABSTRACT
Fruit are susceptible to quality loss and deterioration after harvest due to high metabolic and physiological activities. Over the last four decades various postharvest treatments have ensured maintenance of quality, control of diseases or decay by slowing down the postharvest ripening and senesce. The fruit quality change during postharvest however, has been mostly explored using physicochemical characteristics. Considering the complexity of fruit physiology and metabolism, the application of omics techniques could aid the in-depth analysis and understanding of fruit quality change during postharvest treatment. Therefore, this review presents recent information on the application of integrated omics (transcriptomics, proteomics, and metabolomics) in postharvest research, with an overview on fruit quality and safety. Trends in omics data analysis for fruit during postharvest handling was highlighted. The role of integrated omics in improving our understanding of fruit response during natural postharvest progression (towards decay) during storage, as well as in case of induced responses due to the application of biocontrols was discussed. The article concluded with the outlooks of future studies on the application of integrated omics as the catalyst for innovative postharvest solutions.
ABSTRACT
Pathogens exposed to agricultural production environments are subject to multiple stresses that may alter their survival under subsequent stress conditions. The objective of this study was to examine heat and starvation stress response of Escherichia coli O157:H7 strains isolated from agricultural matrices. Seven E. coli O157:H7 isolates from different agricultural matrices-soil, compost, irrigation water, and sheep manure-were selected, and two ATCC strains were used as controls. The E. coli O157:H7 isolates were exposed to heat stress (56°C in 0.1% peptone water for up to 1 h) and starvation (in phosphate-buffered saline at 37°C for 15 days), and their survival was examined. GInaFiT freeware tool was used to perform regression analyses of the surviving populations. The Weibull model was identified as the most appropriate model for response of the isolates to heat stress, whereas the biphasic survival curves during starvation were fitted using the double Weibull model, indicating the adaptation to starvation or a resistant subpopulation. The inactivation time during heating to achieve the first decimal reduction time (δ) calculated with the Weibull parameters was the highest (45 min) for a compost isolate (Comp60A) and the lowest (28 min) for ATCC strain 43895. Two of the nine isolates (ATCC 43895 and a manure isolate) had ß < 1, indicating that surviving populations adapted to heat stress, and six strains demonstrated downward concavity (ß > 1), indicating decreasing heat resistance over time. The ATCC strains displayed the longest δ2 (>1,250 h) in response to starvation stress, compared with from 328 to 812 h for the environmental strains. The considerable variation in inactivation kinetics of E. coli O157:H7 highlights the importance of evaluating response to stress conditions among individual strains of a specific pathogen. Environmental isolates did not exhibit more robust response to stress conditions in this study compared with ATCC strains.
Subject(s)
Colony Count, Microbial , Escherichia coli O157 , Adaptation, Physiological , Animals , Hot Temperature , Manure , SheepABSTRACT
Wheat (Triticum aestivum L.) plays a central role in the health and nutrition of humans. Yet, little is known about possible flavor differences among different varieties. We have developed a model system using the house mouse (Mus musculus L.) to determine feeding preferences as a prelude to extending results to human sensory analysis. Here, we examine the application of a single-elimination tournament design to the analysis of consumption preferences of a set of hard red and hard white spring wheat varieties. A single-elimination tournament design in this case pairs 2 wheat varieties and only 1 of the 2 is advanced to further tests. Preferred varieties were advanced until an overall "winner" was identified; conversely, less desirable varieties were advanced such that an overall "loser" was identified. Hollis and IDO702 were the winner and loser, respectively, for the hard red varieties, and Clear White 515 and WA8123 were the winner and loser, respectively, for the hard white varieties. When using the more powerful protocol of 14 mice and a 4-d trial, differences in mean daily consumption preferences of 2 varieties were separated at P-values as small as 2 × 10(-8) . The single-elimination tournament design is an efficient means of identifying the most and least desirable varieties among a larger set of samples. One application for identifying the 2 extremes in preference within a group of varieties would be to use them as parents of a population to identify quantitative trait loci for preference.
