The use of HACCP systems to guarantee the production of safe food products for consumers has become very popular over the past few decades. The HACCP technique is a logical, straightforward control system based on the prevention of problems; in other words, the HACCP program uses common sense to manage food safety.1-2
To implement a functioning HACCP system, five successive steps are recommended:
- Observing the process/product from beginning to end;
- Identifying potential hazards and determining which part of the process they may arise in;
- Establishing controls and supervising them;
- Keeping written records of everything; and
- Ensuring that the system continues to work efficiently.
The object of this article is to present adequate options for monitoring control points in a mycotoxin HACCP system. Of course, a good HACCP system has to be capable of coping with all factors that put the production chain at risk, not just mycotoxins.
First, certain concepts must be made clear, especially regarding the characterization of hazardous mycotoxins. Although mycotoxins are chemical compounds that appear as residues in food, they are considered biological hazards instead of chemical hazards because their presence is a direct consequence of fungal contamination occurring at some point in the system.3-4
Cereals and nuts are the food products most sensitive to mycotoxin contamination. Nonetheless, these residues can also be detected in products of animal origin, such as milk, meat, and eggs, and in plant products such as coffee, wine, and dried fruit, among others. The number of foods that can be contaminated by mycotoxins is as vast as the types of contaminating mycotoxins; therefore, establishing a single model for a mycotoxin control system in foods is no simple task.
Monitoring Methods: Fungal or Mycotoxin Analysis?
The fact that mycotoxins are considered biological hazards could lead us to believe that the correct methods for monitoring control points are those that detect, quantify, identify, and classify fungi. However, we must first consider that although in many cases the different processes eliminate fungi from the substrate, mycotoxins are so stable they remain throughout the food processing chain; in other situations, potential mycotoxigenic fungi might be detected but are not producing toxins because it is either a non-producing strain, the substrate is inadequate, or just because the environmental conditions are not propitious for generating the mycotoxin in question.
In addition to a possible lack of correlation between the presence of potentially toxigenic fungi and mycotoxins in a particular food product, we must consider the available methods of fungal analysis in foods:
- Counting, identification, and classification: The disadvantage of these characterization methods for detecting microbial contamination is the time required to reach a useful answer—in other words, counting and identifying potentially toxigenic strains and their capacity to produce mycotoxins in the studied substrate. Obtaining the end results for a single isolated strain can take between two to three weeks, highly inconvenient for monitoring a control point in a food production process.
- Molecular biological methods: Several methods for detecting toxigenic fungi based on molecular biology are being investigated. However, the most approximate methods are those based on real-time polymerase chain reaction, which have a number of limitations when applied at an industrial scale. First, few specific genes involved in the production of mycotoxins have been established—the fusarium genes Tri4, Tri5 and Tri6 for detecting species producing Group A and Group B trichotecenes are an example. Moreover, although genes associated with other species producing aflatoxins and sterigmatocystin (nor-1, ver-1, aflR, omt-A, among others) are useful for discriminating these species from other fungi, they are not highly specific and it is not clear whether they can discern mycotoxigenic strains from non-producing strains within a particular species—for example aspergillus flavus. Another disadvantage of using real time PCR for detecting toxigenic fungi is that it is only capable of detecting the fungi when it is actively producing toxins, limiting the use of this test when the fungi are inactive or growing under conditions that are unfavorable for producing mycotoxins.
- The future of detecting and quantifying mycotoxigenic fungi is based on microarray technology (biochips). This technique allows comparative and simultaneous analyses of hundreds of genes in a device similar to a slide, in a very short period of time. However, many studies have yet to be undertaken that include species-specific gene fragments and sequences with phylogenetic information on the potential mycotoxin-producing species, together with essential genes for mycotoxin biosynthesis.5-6
The previous description not only shows how highly complex and time-consuming it is to establish a monitoring system at a control point by trying to determine toxigenic fungi, but it also highlights the limitations of the methods used for detecting whether the fungi is producing the mycotoxins we are trying to control. Hence, the aforementioned methods are very useful for establishing studies regarding the existence and production of mycotoxins by fungi in certain foods and environments, which would allow a hazard analysis, but are not applicable in the monitoring HACCP system once implemented. For this reason, methods that analyze the mycotoxins present along the production chain of food products are chosen for monitoring control points.