The Challenge of addressing Salmonella Serovars in Different Matrices
Salmonella is one of the key pathogens when we talk about food safety. Similarly, Salmonella control is a top priority for regulatory agencies, public health organizations, and food production companies based on the steady number of associated foodborne illnesses.
Despite the effort to better understand salmonellosis and manage Salmonella during food production, the number of cases remains high, so it is and must be considered a food safety hazard. The more than 2.500 Salmonella serovars described and the diversity among them, in the severity and risk of causing salmonellosis, makes Salmonella management a major challenge for the food industry at different levels in the production chain, from the raw materials, finished products or the presence of the pathogen in the production lines.
Although understanding salmonellosis is difficult, there is valuable knowledge and public health data that is helping identify risk points and address the situation to better manage Salmonella presence at the consumer level. There is a direct association between raw poultry and salmonellosis that is driving regulations in many countries to become more restrictive in the control of Salmonella. This affects the accepted limits, sanitations procedures, testing programs and microbiological control. Also, previous risk assessments have indicated that there is a dose-response relationship between the number of Salmonella of certain serovars present in the food and the severity and number of individuals infected after consumption of contaminated poultry products.
Despite Salmonella spp. being a leading cause of foodborne illness worldwide, the serovars S. Enteritidis (SE) and S. Typhimurium (ST) are often highlighted in food safety programs, particularly in poultry products, as these are the most reported and the ones that cause the most severe illness.
Therefore, the seriousness of this food pathogen requires food processors to engage in food safety management, including sampling and testing programs for Salmonella. Also, the need to confirm the absence of ST and SE in poultry products, results in a daily challenge for quality assurance laboratories to obtain rapid and accurate results.
Rapid detection methods have been used by the food processing industry for years to detect extremely low levels of Salmonella, however, there is still a high presence of traditional methods that do not allow fast enough results to prevent Salmonella contaminated products from reaching the consumers.
Based on currently available commercial technology, a sample enrichment step is required to reliably and qualitatively detect low levels of Salmonella in food products. Qualitative detection of foodborne pathogens indicates presence or absence in the test portion analyzed to meet the criteria of most regulations.
Quantitative data would be useful to food processors of raw agricultural products to better understand the extent of contamination for a given sample type and point in the process or environment. However, the current methods are time-consuming, labor intensive, expensive and the accuracy of the results can be compromised by the many variables that add heterogeneity to the assay (background flora, state of the pathogen, injured or stressed cells, etc).
Food processing needs rapid, cost-effective methods that provide qualitative information on presence or absence of Salmonella to meet the regulatory requirements and to better support process control and pathogen management, and prevent that contaminated products reach the consumers.
It is in this respect where DNA based methods, especially real-time PCR, are the most accurate, stable and robust methods for the rapid detection of presence/absence of food pathogens. DNA-based technology allows the specific detection of the target sequence, the addition of control and the reliable detection regardless of the cell constitution. These aspects can be compromised with other methodologies where the target is not DNA, but antigens or proteins.
One of these methods, the iQ-Check real-time PCR from Bio-Rad is a reliable, specific, sensitive and internationally validated alternative method for screening of Salmonella spp.
The iQ-Check PCR method can be adapted to the circumstances of every lab by implementing a manual DNA extraction method or using the power of automation with the iQ-Check Prep. The iQ-Check Prep Solution improves use of lab staff time, it significantly reduces technical errors that cause delays and damage credibility. Robustness and flexibility make the iQ-Check Prep Solution an ideal fit for medium and high throughput labs. It is part of a complete automated solution that includes systems, kits, consumables, software, service, and support to streamline food pathogen and cannabis testing workflows.
In the USA, regulations require targeted monitoring in poultry/egg production and in Europe, regulations have been implemented to monitor S. Enteritidis and S. Typhimurium in poultry, from the primary production stage to the food products. The early detection of environmental contamination is a key point for a successful S. Enteritidis and S. Typhimurium risk management. iQ-Check S. Enteritidis Kit and iQ-Check S. Typhimurium are simple and rapid qualitative tests suitable for the detection of these serovars in pooled eggs, poultry meat and environmental samples of primary production.
In conclusion, the iQ-Check real-time PCR system demonstrates to be a reliable, specific and sensitive alternative method for the screening of Salmonella spp. and serotyping of S. Typhimurium and S. Enteritidis in poultry samples. The release of negative reports in 22–26 hr ensures process costing savings in the food industry and a fast risk management of this food pathogen.