Proficiency Testing Australia
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PTA has scheduled the Pathogens in Food (Round 36) proficiency testing program in September 2017.  This is an important proficiency testing program for food safety which includes the testing for Listeria.  

Listeria are common organisms.  Listeria monocytogenes is considered to be a foodborne pathogen.  

Listeria monocytogenes is a deadly species of foodborne bacteria that, if ingested can cause severe infection listeriosis,  This can lead to a range of serious health conditions in humans, such as meningitis, gastroenteritis, and bacteraemia, and has a fatality rate as high as 30% in people who are high-risk including pregnant women, elderly people and young children.  

Listeria monocytogenes is exceptionally good at surviving and growing in cool, wet conditions and can be very difficult to eradicate once established.  Once the organism inhabits such an environment, it can contaminate foods prepared in these areas and continue to grow even in products stored under very good chilled conditions in retail chillers and domestic fridges.

Consequently there are many opportunities for Listeria monocytogenes contamination during the food production process.  Common causes of transmission to humans have been via consumption of contaminated ready to eat food products including raw vegetables, meat and fish, and dairy products such as ice cream and soft cheeses.  


In 2011 the USA began suffering one of the largest outbreaks of listeriosis ever recorded with 146 reported illnesses and 30 deaths.  The source of the outbreak was from fresh cut rockmelons.  The US Food and Drug Administration inicated that the outbreak arose through a mixture of low level field contamination, inadequate cooling of the harvested melon, a packhouse design that allowed water to pool and was difficult to clean, and potential cross contamination of melon from other raw agricultural products handled in the packhouse.

It is clear that food safety professionals need to expand their views on the types of food liable to cause listeria monocytogenes related problems.

It is essential that food manufacturers have environmental screening programs in place for listeria mononcytogenes to enable prompt detection and mitigation of contamination.

Laboratories that participate in the PTA Pathogens in Food proficiency testing program will be able to demonstrate their competence for food safety testing.