What are the disadvantages of animal cell culture?

Animal cell culture is a process of extracting animal cells and growing them in vitro, outside of their environment under controlled conditions. Scientists use animal cell cultures extensively in various studies, including those involved in diagnosing infections and testing new drugs. While animal cell culture offers several advantages, it has a few disadvantages as well. Animal cell culture poses these disadvantages: 

• It can be challenging to maintain sterile aseptic conditions in vitro.
• There are challenges involved in maintaining proper concentration of nutrients and serum, and standardization of medium as they vary among different cell types and their origin. 
• There is a high possibility of microbial and chemical contamination as well as cross contamination among different types of cells in culture. 
• There is a high possibility of cells undergoing chemical, physical and physiological changes, induced by the micro-environment inside the culture container. 
• Chances of genetic variation within a single cell population are very high because of the rapid growth rate of cells in artificial culture. 
• It is often difficult to identify cell types as the expression of marker proteins are often insufficient under in vitro conditions. 
• Setting up a cell culture requires a very high capital investment. 
• Proper maintenance of the cells requires considerable experience and expertise. 
• There are a limited number of passages in most of the primary cells in culture.