Zero Risk Does Not Exist: Lessons Learned from Microbial Risk Assessment Related to Use of Water and Safety of Fresh Produce

Risk assessments related to use of water and safety of fresh produce originate from both water and food microbiology studies. Although the set‐up and methodology of risk assessment in these 2 disciplines may differ, analysis of the current literature reveals some common outcomes. Most of these studies from the water perspective focus on enteric virus risks, largely because of their anticipated high concentrations in untreated wastewater and their resistance to common wastewater treatments. Risk assessment studies from the food perspective, instead, focus mainly on bacterial pathogens such as Salmonella and pathogenic Escherichia coli. Few site‐specific data points were available for most of these microbial risk assessments, meaning that many assumptions were necessary, which are repeated in many studies. Specific parameters lacking hard data included rates of pathogen transfer from irrigation water to crops, pathogen penetration, and survival in or on food crops. Data on these factors have been investigated over the last decade and this should improve the reliability of future microbial risk estimates. However, the sheer number of different foodstuffs and pathogens, combined with water sources and irrigation practices, means that developing risk models that can span the breadth of fresh produce safety will be a considerable challenge. The new approach using microbial risk assessment is objective and evidence‐based and leads to more flexibility and enables more tailored risk management practices and guidelines. Drawbacks are, however, capacity and knowledge to perform the microbial risk assessment and the need for data and preferably data of the specific region.     

Experimental test of the valence-instrumentality relationship in job performance.

Tested expectancy-valence models of work motivation which postulate an interactive relationship between valence of outcomes and performance-outcome instrumentality. Ss were 60 college-age respondents to an ad for part-time clerical work. Valence of job outcomes was set at 2 levels (high and low) by establishing 2 different pay rates; performance-outcome instrumentality was determined by paying wages hourly (low instrumentality) or by the piece (high instrumentality). It was hypothesized that these variables would combine interactively to affect task performance and effort. While main effects for both performance-outcome instrumentality and valence of job outcomes were observed, the predicted interaction did not appear. Results suggest that the typical conceptualization of valence as the importance an individual attaches to an outcome may be inappropriate. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task-relevant information, social reinforcement, and race as factors affecting performance: A re-appraisal.

In a recent study, J. Tedeschi and T. Levy (see record 1971-28825-001) related responsiveness to social reinforcement in chance vs. skill tasks to previous findings of external control in lower-class blacks and internal control in middle-class whites. In the present article, P. Burgess examines the rationale behind Tedeschi and Levy's predictions, questions the validity of their experimental paradigm, and suggests that their results do not provide adequate support for their conclusions. In a separate article, Tedeschi & Levy reply to Burgess's criticisms. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variations in the leaf standard,chemical composition and quality of black tea (Camellia sinensis) due to plucking intervals

Green leaf standard, chemical composition and quality of black tea (Camellia sinensis (L) O Kuntze) change with plucking intervals. Long plucking intervals lead to poor leaf standard with a lot of mature leaves and lower theaflavins, the sum of volatile flavour compounds imparting a sweet flowery aroma (group II volatile flavour compounds), caffeine contents and tasters' evaluations of black tea. The sum of volatile flavour compounds imparting inferior, grassy, green flavour (group I volatile flavour compounds) to tea, however, increases with long plucking intervals.     

Nitroureas II. Synthesis of Bicyclic Mono- and Dinitrourea Compounds

We report the synthesis and characterization of several bicyclic mono- and dinitrourea compounds as energetic materials and discuss their use as precursors to other energetic compounds. The new nitrolyzing reagent, trifluoromethanesulfonic acid anhydride/20% N₂O₅/nitric acid, will also be described.