Page 5 - National Poultry Newspaper

Simple solution to ensure raw egg safety
SALMONELLA is a key cause of foodborne gastroenteritis in Aus- tralia and case numbers are increasing, with most outbreaks linked to eggs, poultry meat, pork, dairy and fresh produce.
Flinders University re- searchers have found a simple solution for pre- venting salmonellosis affecting eggs through surface contamination, giving crucial assis- tance to Australia’s vast food services industry.
Raw eggs are used in many food products such as mayonnaise, mousse, eggnog and ar- tisanal ice cream.
However, a problem is associated with egg- shells being contami- nated with the bacteri- um salmonella enterica serovar typhimurium.
The Flinders research team aimed to develop a decontamination meth- od for removing ST from the eggshell with- out impacting usability.
Using equipment com- monly found in com- mercial kitchens, the researchers decontami- nated eggs by placing them in a sous vide cooker with water heat- ed to 57C.
Complete decon- tamination of ST was achieved by treating eggs for nine minutes.
The results of the first study to look at decon- tamination of ST on the eggshell were recently
published in the journal ‘Foodborne Pathogens and Disease’.
The decontaminated eggs were found, by chefs using measure- ments and acceptabil- ity scores, to have no significant difference in their quality or per- formance as an ingre- dient when compared with nontreated eggs.
You can go online to find a preview of ‘A Successful Technique for the Surface Decon- tamination of Salmo- nella enterica Serovar Typhimurium External- ly Contaminated Whole Shell Eggs Using Com- mon Commercial Kitch- en Equipment’ (Novem- ber 2019), a paper by Thilini Keerthirathne, Kirstin Ross, Howard Fallowfield and Harriet Whiley.
A second study by the Flinders environ- mental health research team examined the effectiveness of current Australian guidelines recommending raw egg mayonnaise should be prepared and stored un- der 5C and adjusted to a pH less than 4.6 or 4.2.
Despite these guide- lines, a significant num- ber of salmonellosis outbreaks continue to be recorded every year in Australia.
The researchers found the survival of salmo- nella typhimurium in mayonnaise is signifi- cantly improved at 4C
and lower temperatures protected ST from the bactericidal effect of low pH.
Flinders environmen- tal health researcher Thilini Keerthirathne said, “We found the preparation of may- onnaise at pH 4.2 or less and incubating it at room temperature for at least 24 hours could reduce the incidence of salmonellosis.”
“But there is a risk storing mayonnaise at 37C.
“If the pH is not cor- rectly measured, the warmer temperatures will promote the growth of salmonella.
“As such, it is crucial to ensure the pH of the mayonnaise is at pH 4.2 or less.”
This study, ‘The Com- bined Effect of pH and Temperature on the Survival of Salmonella enterica Serovar Typh- imurium and Implica- tions for the Preparation of Raw Egg Mayon- naise’ (November 2019) by TP Keerthirathne, K Ross, H Fallowfield and H Whiley, has been published in ‘Patho- gens’ journal.
PhD candidate Ms Keerthirathne said the results of the two stud- ies will help decrease the current levels of foodborne salmonello- sis outbreaks related to eggs and raw egg prod- ucts in Australia.
It is estimated 4.1 mil-
lion cases of foodborne illness are recorded annually nationwide, including 30,000 hospi- talisations and 100 fa- talities.
Salmonellosis is one of the most prevalent causes of foodborne illness in the country, increasing from 40.9 per 100,000 popula- tion in 2005 to 71.5 per 100,000 population in 2015.
A common source of salmonellosis has been identified as raw eggs and egg products. Background
Salmonella entericais
is transmitted via food, the environment, water, people and animals, and often causes gastroen- teritis in humans.
Common foods asso- ciated with salmonello- sis in outbreak investi- gations and source at- tribution studies include eggs, poultry meat, pork, beef, dairy prod- ucts, nuts and fresh pro- duce.
More than 70 percent of salmonellosis in Aus- tralia is estimated to be transmitted through contaminated food.
Worldwide salmonella infections, excluding those caused by S. typhi and S. paratyphi, were estimated to cause 93.8 million cases of gastro- enteritis per year, 80.3 million of which are considered foodborne.
Flinders University researcherThilini Keerthirathne investigated salmonellosis on eggshells.
Eggs on toast.
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National Poultry Newspaper, March 2020 – Page 5
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