Microbiology of egg and egg products

Abstract

The risk of contamination by microorganisms, and mostly by Salmonella, is a major concern in the sectors of egg production and eggproduct manufacturing. Under healthy breeding conditions, the egg content is generally sterile. However, it can be contaminated bya diversified microbiota containing food spoilage microorganisms and sometimes pathogenic bacteria. The egg has however remarkableself-defence properties intended to preserve the embryo of any microbial invasion during its development. This article gives aprogress report on the origin of egg contamination and on egg’s antimicrobial defence mechanisms. The means to limit the presenceand the development of microorganisms in eggs are discussed, at the egg production level, and during egg storage and conditioning.Egg breaking systematically involves the contamination of egg white and egg yolk through contact with the spoiled shells, thusgiving rise to highly perishable egg products. The control of their microbiological quality is required, in particular when they are integratedin raw or undercooked food. The means of control are discussed and particularly the respect of good hygiene practices andrelevant stabilization processes. The significance of monitoring temperatures for the control of pathogenic and food spoilage microorganismsis particularly underlined.