There’s a fly in the facility and Walter doesn’t want to proceed until the fly is dealt with. Walter doesn’t want to contaminate the product in any way, but Jesse is confused because the customers don’t care about the quality of the product. If a small fly lands in the batch, Jesse believes it won’t be that big of a deal because the customers are highly inelastic. Jesse cites other examples of contamination in food (like hot dogs and candy bars) where people (and the government) don’t care about the quality.
See more: elasticity of demand, government regulation, quality