Final answer:
A slice of cheese goes under the slices of ham in a sandwich according to the provided information. There are 5 pickles needed as per the ham sandwich's recipe. Mayonnaise is acidic and doesn't usually cause bacterial growth; poor temperature control and cross-contamination are likelier culprits.
Step-by-step explanation:
The question 'What goes under all sliced meats?' in the context of sandwich making, does not have a single correct answer because it depends on personal preference or the specific recipe being followed. However, based on the information provided about the ham sandwich composition, a slice of cheese (C) is the ingredient listed that goes underneath the slices of ham (H). In the given equation for our sandwich, the cheese would be placed under the ham before the toppings like pickles, tomato, etc.
Regarding the question on the number of pickles (P) needed, if the ham sandwich requires 2 slices of ham and the equation states 5 pickles, the ratio between ham slices and pickles is 2:5. Therefore, 5 pickles are needed for this particular sandwich recipe. This quantity is not necessarily a standard but part of this specific equation.
As for the myth related to mayonnaise, the reality is that mayonnaise is not typically responsible for bacterial growth, as it is acidic enough to prevent such growth. Instead, improper temperature control during food storage, especially at events like picnics, and cross-contamination with other non-acidic foods are more likely causes of foodborne illness.