# An Overview of the Public Health Challenges in Diagnosing and Controlling Human Foodborne Pathogens
## 4 Diagnostic Approaches of Foodborne Pathogens
### Culture Techniques  
In order to cultivate, isolate, count and develop the target microbe, the cultural methods use specific liquid or solid culture media, while simultaneously suppressing the growth of additional microbes present in the sample. During the process of determining foodborne pathogens, pre-enrichment growths, selective enrichment cultures and selective plating are used. Afterwards, serology and biochemistry are used to confirm the results. There is a wide range of approaches to understanding culture, both qualitatively and quantitatively [104]. Among the most fundamental microbiological techniques are the cultivation of bacterial and fungal cultures in vitro on nutritional media [105] because of their simplicity and straightforwardness of observation. In this approach, it is believed that food pathogens are identified by cultivating microorganisms on agar plates, followed by routine, specialized biochemical and serological tests for further identification of the organisms [106; 107]. Agar media serve as a suitable medium for growing bacteria, which results in the formation of colonies when the bacteria grow in that medium. In terms of phylogenetic diversity, morphology and metabolism, fungi are more diverse than bacteria, and they are more culture-friendly than bacteria [107]. Bacteria and fungi that cause disease in humans are classified according to their morphology, which includes the size and form of their colonies, the color in the culture and the size and form of their cells, as well as their ability to reproduce. As a result of the pioneering work of [PERSON], a number of criteria have been established that must be met for a bacterium to be labeled a disease-causing pathogen, a concept sometimes referred to as [PERSON]'s postulates [108]. Several chromogenic/fluorescent media have been developed in order to replace traditional culture plating as well as to eliminate the need for subcultures and biochemical assays for microbial identification in order to replace traditional culture plating [109]. There are a wide variety of bacteria and fungi that are found in a variety of samples, so the lab workers would examine these samples and identify, isolate and distinguish particular bacterial or fungal diseases. Using chromogenic/flurogenic media, it is only required to use a very small amount of material in order to identify harmful bacteria and molds. Whether it is culture broth or agar media, the presence of microbes can be detected through color production or fluorescence [110; 111]. During chromogenic or fluorogenic substrate hydrolysis by a special enzyme produced by the microorganisms, a colored or luminous product is created, also known as color creation or fluorescence [112]. Because the activity of many enzymes is not species-specific, screening agents or enzymatic activity that is supplementary or secondary to the enzyme's activity may be used to help determine the species of interest. In chromogenic media, selective agents (often antibiotics) are utilized to provide both positive as well as negative selection, as they are able to support the growth of target bacteria as well as inhibit the growth of non-target bacteria in the sample matrix [113]. For improved recognition and accuracy of bacterial selection and identification, it is possible to combine a number of distinct chromogenic enzymes and selective agents when using this method. A majority of the research on the chromogenic properties of enzymes is focused on the bacterial hydrolases (\(\beta\)-glucosidase or \(\beta\)-galactosidase in particular) [114; 115]. As a result of the reaction between the chromogenic substrate and the bacterial enzyme, the substrates are given a vibrant color. The colonies are further differentiated by the presence of an enzyme that specifically recognizes the substrate. Figure 1: Detection of foodborne pathogens using various diagnostic approaches.