We consider a three-level food chain in which an epidemics affects the intermediate population. Two models are presented, respectively either allowing for unlimited food supply for the bottom prey, or instead assuming for it a logistic growth. Counterintuitive results related to the paradox of enrichment are obtained, showing that by providing large amounts of food to the bottom prey, the top p...

Paradoxically, enrichment can destabilize a predator-prey food web. While adaptive dynamics can greatly influence the stability of interaction systems, few theoretical studies have examined the effect of the adaptive dynamics of interaction-related traits on the possibility of resolution of the paradox of enrichment. We consider the evolution of attack and defence traits of a predator and two p...

For foodborne outbreak investigations it can be difficult to isolate the relevant strain from food and/or environmental sources. If the sample is contaminated by more than one strain of the pathogen the relevant strain might be missed. In this study mixed cultures of Salmonella enterica were grown in one set of standard enrichment media to see if culture bias patterns emerged. Nineteen strains ...

Past evaluations of pesticide exposure have been conducted with substantial uncertainty regarding avian consumption of contaminated food items. One question is whether birds consume invertebrates that are killed by a chemical application and that may present an increasing chemical concentration as they desiccate. We addressed the research question in two phases. First, a laboratory study was co...

A review of the literature has revealed a scarcity of attempts to compare directly various methods proposed for the detection of Salmonella organisms in food products. Unfortunately, often it has been assumed that methods useful in clinical or public health laboratories, engaged in identifying cases and carriers, are also suitable for the examination of food products. Furthermore, in many insta...

The ex situ population of maned wolves is not self-sustaining due to poor reproduction, caused primarily by parental incompetence. Studies have shown that environmental enrichment can promote natural parental behaviors in zoo animals. The objective of this study was to determine the effects of environmental enrichment on behavioral and physiological responses of maned wolves. During an 8-week e...

A review of the literature has revealed a scarcity of attempts to compare directly various methods proposed for the detection of Salmonella organisms in food products. Unfortunately, often it has been assumed that methods useful in clinical or public health laboratories, engaged in identifying cases and carriers, are also suitable for the examination of food products. Furthermore, in many insta...

Most aquatic and terrestrial ecosystems are experiencing increased nutrient availability, which is affecting their structure and function. By altering community composition and productivity of consumers, enrichment can indirectly cause changes in the pathways and magnitude of material flows in food webs. These changes, in turn, have major consequences for material storage and cycling in the eco...