FOOD PATHOGEN DETECTION

The detection and enumeration of pathogens in food and on surfaces that come into contact with food are an important component of any integrated program to ensure the safety of foods throughout the food supply chain. Both government authorities and food companies use microbiological analysis to monitor the state of contamination at all times and analyze its trends so as to detect emerging risks. Microbiological analysis is also an essential tool for carrying out tests in accordance with the micro-biological criteria established for each food type, as well as being essential for evaluating the actions of different management strategies based on the Hazard Analysis and Critical Control Points (HACCP) system. The implementation of preventive systems such as the HACCP has greatly improved food safety, but it will not be fully effective until better methods of analysis are developed. These new detection methods are the necessary technologies that will substantially improve our food safety once integrated in the HACCP.

Microbiological analysis of foods is based on the detection of microorganisms by visual, biochemical, immunological, or genetic means, either before enrichment (quantitative  or  enumerative  methods)  or  after  enrichment  (qualitative  methods, also known as presence/absence tests).

In spite of its importance, the microbiological analysis of food has many limita-tions.  Uncertainty  of  the  analytical  result  must  be  considered  when  establishing microbiological criteria, including the variance associated with the sampling plan, method  of  analysis,  and  laboratory  performance . The microbiological analysis of food remains a challenging task for virtually all assays and technologies, especially for particular pathogenic species.

The problems may be due to

·         The complexity of food matrices and composition.  

·         The heterogeneous distribution of low levels of pathogens.   

·         The stress suffered by the microorganisms during the processing of foods.  

·         The presence of bacteria from the normal microbiota, especially in raw foods.   

The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNAmicroarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.