Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2024

Evaluation of bioprotective bacteria to reduce Campylobacter on raw chicken meat at the end of primary processing. (104606)

Anran Dong 1 , Deirdre Mikkelsen 1 , Mark S Turner 1 , Jillian M Templeton 2
  1. School of Agriculture and Food Sustainability, University of Queensland, Brisbane, Qld, Australia
  2. Department of Agriculture and Fisheries, Queensland, EcoSciences Precinct, Dutton Park, Queensland, Australia

 Campylobacter enteritis is the mostcommon notifiable foodborne infection in humans in Australia. Poultry meat, while not the sole contributor, is accepted as one of the major sources of Campylobacter for humans. Sporadic cases are reported in Australia annually (41,000 cases in 2023) (NNDSS 2023), which have a significant estimated economic cost ($365 million in 2019) (FSANZ 2022). The estimated gross value of Australian poultry production is over $2.5 billion per year and growing (Australian Chicken Meat Federation), with the annual per capita chicken meat consumption being approximately 50 kg. Due to the widespread consumption of chicken meat, it is imperative to continue to help mitigate the risk of human illness by minimising pathogen levels on raw chicken meat. Numerous techniques such as chilling, sanitising chemicals, modified atmosphere packaging (MAP) and vacuum packaging are employed during processing to decrease Campylobacter levels on raw chicken meat. However, the continued persistence of these pathogens on chicken and the pressure to replace ‘chemical sanitisers’ remains a challenge. This project aims to identify and assess bioprotective bacteria capable of reducing Campylobacter counts on raw chicken meat. More than 1,000 generally recognised as safe (GRAS) lactic acid bacteria (LAB) were isolated from both raw chicken meat and fresh produce using two different plating temperatures (22 and 30 °C). Using a microtiter plate-based assay, LAB strains were evaluated for their efficacy of Campylobacter killing, with more than 90% of the isolates causing a reduction of Campylobacter counts by >2 log10 colony forming units (CFU)/ml. An important aspect of the reduction was due to organic acid produced by the LAB, as neutralising the pH of the LAB suspension abolished the killing effects for most strains. Furthermore, utilising 16S rRNA gene PCR and sequencing, 500 LAB isolates were identified to species level, which revealed a diverse range of GRAS LAB genera and species. Notably, distinct LAB species were isolated at 22 °C compared to 30 °C. If successful, this research will offer the industry a straightforward, safe and cost-effective method to reduce Campylobacter levels on chicken meat, thereby helping to mitigate one of the risks associated with illnesses.