Pre-harvest food safety is all about protecting our food supply from pathogens, parasites, and other harmful agents. This 4-part curriculum is the leader's guide for a 4-H project on principles and methods that youth can apply in food-animal projects.

Raising and Protecting a Healthy Animal is part 3 of a 4-part curriculum introducing 4-H youth to pre-harvest food safety principles and methods to use in their livestock and poultry projects and in later life.

Food-Producing Animal Selection and Pre-Harvest Food Safety Considerations is part 2 of a 4-part curriculum introducing 4-H youth to pre-harvest food safety principles and methods to use in their livestock and poultry projects and in later life.

Decision-Making and Owner Responsibilities is part 4 of a 4-part curriculum introducing 4-H youth to pre-harvest food safety principles and methods to use in their livestock and poultry projects and in later life.

Assessing Critical Control Points Associated with Disease Transmission is part 1 of a 4-part curriculum introducing 4-H youth to pre-harvest food safety principles and methods to use in their livestock and poultry projects and in later life.

Environmental toxicants have the potential to contribute to the pathophysiology of multiple complex diseases, but the underlying mechanisms remain obscure. One such toxicant is the widely used fungicide ziram, a dithiocarbamate known to have neurotoxic effects and to increase the risk of Parkinson's disease. We have used Drosophila melanogaster as an unbiased discovery tool to identify novel molecular pathways by which ziram may disrupt neuronal function. Consistent with previous results in mammalian cells, we find that ziram increases the probability of synaptic vesicle release by dysregulation of the ubiquitin signaling system. In addition, we find that ziram increases neuronal excitability. Using a combination of live imaging and electrophysiology, we find that ziram increases excitability in both aminergic and glutamatergic neurons. This increased excitability is phenocopied and occluded by null mutant animals of the ether a-go-go (eag) potassium channel. A pharmacological inhibitor of the temperature sensitive hERG (human ether-a-go-go related gene) phenocopies the excitability effects of ziram but only at elevated temperatures. seizure (sei), a fly ortholog of hERG, is thus another candidate target of ziram. Taken together, the eag family of potassium channels emerges as a candidate for mediating some of the toxic effects of ziram. We propose that ziram may contribute to the risk of complex human diseases by blockade of human eag and sei orthologs, such as hERG.

Octopamine is essential for egg-laying in Drosophila melanogaster, but the neuronal pathways and receptors by which it regulates visceral muscles in the reproductive tract are not known. We find that the two octopamine receptors that have been previously implicated in egg-laying-OAMB and Octβ2R-are expressed in octopaminergic and glutamatergic neurons that project to the reproductive tract, peripheral ppk(+) neurons within the reproductive tract and epithelial cells that line the lumen of the oviducts. Further optogenetic and mutational analyses indicate that octopamine regulates both oviduct contraction and relaxation via Octβ2 and OAMB respectively. Interactions with glutamatergic pathways modify the effects of octopamine. Octopaminergic activation of Octβ2R on glutamatergic processes provides a possible mechanism by which octopamine initiates lateral oviduct contractions. We speculate that aminergic pathways in the oviposition circuit may be comparable to some of the mechanisms that regulate visceral muscle contractility in mammals.