More than 4,000 samples were taken during efforts to investigate outbreaks, according to an Australian state’s annual food testing report for 2018 and 2019.

The New South Wales (NSW) Food Authority reported 4,010 food and environmental samples were submitted for testing between July 2018 and June 2019 as part of foodborne illness investigations, compared to 591 samples between July 2016 and June 2017.

One example described in the latest report was an increase in Salmonella Enteritidis cases since mid-2018. More than 100 locally produced, imported foods and environmental samples were tested for Salmonella, including fresh and dried vegetables, seafood, spices, egg-containing foods, nuts and eggs. Environmental tests were swabs, stock feed, water, and poultry fecal samples as well as eggs.

During the investigation, another 2,072 samples from egg primary production companies were tested, including eggs and environmental samples. Salmonella Enteritidis was found on 13 properties in NSW and one in Victoria interconnected by movements of people, eggs or equipment. It was detected in NSW poultry for the first time in September 2018. More than 220 illnesses were reported in Australia including 193 in NSW linked to the outbreak.

Salmonella and eggs
The NSW Department of Primary Industries increased surveillance and monitoring at egg farms and issued biosecurity directions to certain properties, including quarantining them to prevent movement of eggs into the market.

Other actions included farm depopulation, decontamination and disinfection. The Biosecurity (Salmonella Enteritidis) Control Order was issued in August 2019 to assist in raising long term biosecurity standards. Surveillance and monitoring at egg farms was set to continue in 2020.

Meanwhile, Salmonella Typhimurium cases plateaued or rose slightly in 2018-19. Much of this was linked to one egg farm, which was the source of 20 percent of all such cases in NSW, according to the report. Several visits detected the same type of Salmonella Typhimurium linked to the human cluster. Illness was not helped by poor handling of eggs in some businesses, including failure to clean and sanitize surfaces or equipment, and use of raw egg products.

The farm implemented additional cleaning and sanitizing of farm grading equipment and is looking at vaccinating birds to reduce Salmonella Typhimurium. These measures appear to have been successful, with a decrease in this type of salmonellosis cases in NSW.

RTE food and chicken sampling
DTS Food Assurance is the primary testing provider. Between July 2018 and June 2019, 6,431 samples were submitted for testing: 5,438 to DTS wher 10,756 individual tests were conducted and 993 samples to other laboratories.

Other work saw 162 ready-to-eat food samples randomly collected from 71 businesses and tested. Three products from three manufacturers were non-compliant as two samples of soft cheese contained E. coli greater than the regulatory limit of 10 colony forming units per gram (cfu/g). One gelato had E. coli above this limit. Follow-up actions included inspections from the Food Authority, re-sampling of product for analysis and ongoing compliance activities.

In total 196 whole chickens and chicken portions were collected from processing plants and 312 chicken portions from retail outlets. At processing plants, Salmonella was detected in 21.4 percent of samples and Campylobacter was found in 86.7 percent of samples. At retail, 25.8 percent of samples tested positive for Salmonella and Campylobacter was detected in 89.9 percent of samples.

A retail survey looked at if and how Campylobacter is transferred to ready-to-eat (RTE) products. It involved 22 councils, 169 retail food premises with 593 swabs taken and 281 food samples analyzed. Of 258 RTE chicken and pate samples, two were contaminated with Campylobacter at less than 100 cfu/g. A further 11 samples contained E. coli at 3 to 93 most probable number per gram (MPN/g).

Checks during audits and for Listeria in melon
During the 2018 to 2019 fiscal year, 76 samples of pipis, a type of edible clam, were tested for three main algal toxin groups: amnesic shellfish toxin, paralytic shellfish toxins, and diarrhetic shellfish toxins found in NSW coastal waters. Of these, diarrhetic shellfish toxins were detected in 13 samples. The Algal biotoxins in wild harvest shellfish project is planned to continue into 2019-2020.

Samples taken during audits are usually raw meat that have failed a field test for sulphur dioxide (SO2), which is not permitted in this product. Between July 2018 and June 2019, 1,598 audits of licensed retail meat businesses were conducted and 31 samples of raw meat from 14 butchers were tested for SO2 after positive field tests. Twenty-eight of these from 13 butchers were positive, with values ranging from 13 to 3,600 mg/kg.

Another project was a review of Listeria in rockmelon, also called cantaloupe, packhouses and melons. More than 940 melon and environmental samples were collected to monitor prevalence of Listeria monocytogenes, Salmonella, and standard plate count pre- and post-wash. only one sample was positive for Listeria monocytogenes, which was a boot swab taken from a dis-used cool room. The only Salmonella detected was in untreated water.