Salmonella contamination in shell eggs exposed to modified-pressure imaging for microcrack detection

Area of Science:

• Food Science
• Microbiology
• Agricultural Engineering

Background:

• Microcracks in egg shells pose a food safety risk and are challenging for human inspectors to detect.
• A novel modified-pressure imaging technology demonstrates 99.6% accuracy in identifying eggshell microcracks.

Purpose of the Study:

• To evaluate if the modified-pressure imaging system for microcrack detection leads to increased Salmonella penetration into egg contents.
• To determine if the imaging system causes microbial cross-contamination within the egg processing system.

Main Methods:

• Three replicates of 30 dozen grade A large white eggs were used.
• Eggs were inoculated with nalidixic acid-resistant Salmonella Typhimurium (ST) or sterile buffered peptone water.
• Eggs were incubated, imaged using the modified-pressure system, and subjected to cultural analysis of shell rinse, shell emulsion, and contents.

Main Results:

• Salmonella Typhimurium was not detected on or in control eggs, even those imaged after inoculated eggs.
• The highest ST levels were found in inoculated egg shell emulsions (4.79 log cfu/mL).
• No significant differences in ST levels were observed between imaged and non-imaged inoculated eggs at any sample location.

Conclusions:

• The modified-pressure imaging system for microcrack detection does not increase microbial penetration or cause cross-contamination.
• This imaging technology can be safely employed for assessing eggshell integrity without compromising food safety.