The ISEKI-Food book series is a collection of books in which various aspects of food safety and environmental issues are introduced and discussed by scientists specialized in the field. The final part of the ISEKI-Food book series is a collection of case studies in the field of food safety and environmental health.
EXPLOITATION OF MICROORGANISMS BY THE FOOD
PATHOGENIC, COMMENSAL AND BENEFICIAL
PROCESS SAFETY
CLEANING AND DISINFECTION PROCEDURES IN THE FOOD INDUSTRY GENERAL ASPECTS AND
ENSURING BIOSAFETY THROUGH MONITORING OF GMO IN FOOD WITH MODERN ANALYTICAL TECHNIQUES,
Laboratory of Food Quality Control and Hygiene, Department of Food Science and Technology, Agricultural University of Athens, 75, Iera Odos, Str., Votanikos, Hellas (Greece), EL-118 55. DLWT - Department of Food Science and Technology, BOKU -University of Natural Resources and Applied Life Sciences Vienna, Muthgasse 18, A-1190 Vienna, Austria.
Introduction
Why Do We Need to Preserve?
- The necessity to preserve
Humans like to eat a wide variety of foods that have different flavors, tastes, nutritional, dietary and other properties. The main processes of food spoilage are caused by environmental factors such as temperature, moisture, oxygen and light, which can be the reason for several reaction mechanisms that can lead to food spoilage to the extent that it is either rejected by the consumer or harmful to them.
Conventional Food Preservation Methods
- Food preservation by heat treatment
- Preservation by low water activity (a w )
- Preservation by low pH and organic acid
- Preservation by carbon dioxide, sulphite, nitrite and nitrate
- Preservation by modified and controlled atmospheres
- Irradiation preservation of the foods
- Preservation by low temperatures
The effect of the gaseous environment of the food on microorganisms is less well understood by microbiologists and food technologists than other factors that influence microbial growth, such as pH, aw, etc. Ionization radiation affects bacteria, yeasts and fungi by causing lesions in the genetic material of the cell.
Potential Food Preservation Methods
- Pulsed electric fields
- High pressure
- Ultraviolet radiation
- Sound in food preservation
- Application of bacteriocins in food preservation
It is mainly used in the sterilization of air and thin liquid films due to the low penetration of the waves. The practical application of this has been controversial due to the type and intensity of radiation, methods of assessing the mortality of microorganisms and other factors.
Combined Methods for Food Preservation
Today, about 30 different bacteriocins, produced by about 17 species of lactic acid bacteria, have been identified and their bactericidal activity has been studied. The production of lactic acid and bacteriocins by lactic acid bacteria can provide a safe and natural means of (bio)preservation.
St. Anthony's fire (sacred fire), a disease that affected many parts of Europe in the tenth century, is believed to have been caused by the consumption of toasted rye with ergot alkaloids, a known mycotoxin of Claviceps purpurea (Cast, 2003). Aflatoxins are of particular concern in populations with high levels of hepatitis B as they have been shown to be 60 times higher when humans are exposed to the metabolite.
Mycotoxins and Relevant Fungi
- Aflatoxins
- Ochratoxin A
- Patulin
- Fumonisins, trichothecenes, and zearalenone
However, it is relevant for the detection of areas within the goods system where contamination occurs. However, the main effect of these and other trichothecenes is the immunosuppressive activity, which is probably related to the inhibitory effect on the biosynthesis of macromolecules (e.g. DNA, proteins).
Occurrence of Mycotoxins and their Geographical Distribution
- Aflatoxins
- Ochratoxin A
- Fumonisins, trichothecenes and zearalenone
- Patulin
- Co-occurrence of mycotoxins
- Biocontrol agents (BCAs)
- Warfare
The highest levels were found in barley, oats, wheat and maize in (a) Northern Europe, i.e. in the United Kingdom, Denmark, Sweden and the Balkans (former Yugoslavia) and (b) India (CAST, 2003). High concentrations have been found in developing countries, particularly at more moderate elevations (CAST, 2003).
Control
- Good agricultural practice (GAP)
- Good management practices (GMP)
- Removal of mycotoxins after harvesting
- Removal during processing
- Degradation of mycotoxins
- Others
It is clear that the levels of mycotoxins in the environment used for this purpose will be at higher concentrations than occur in nature. Most interest is in the use of ammonia in the anhydrous form and in aqueous solution.
Legislation and Regulation
- Process standards vs. product standards
The EU has set limits for aflatoxins, Fusarium toxins, OTA and patulin in several food products (Tables 5 to 8). Other countries in Europe have independent restrictions and within the EU each country may have different restrictions for other food ingredients.
Case Studies
- Experimental reduction of OTA in wheat by scouring
- Copra cake and meal––southeast Asia
- Apple juice––South America
Patulin contamination would likely be produced in the orchard during growth and bulk storage. Critical limits are set for the size and quantity of particles remaining in the apple juice after filtration.
Conclusion
Contamination of the juice could be prevented at stages where rotten or decaying apples could have been rejected from the process, either in the orchard when the fruit is harvested or during sorting in the factory (FAO, 2003). There is no information on whether the products met the ultimate goal of the HACCP analysis, which was that the apple juice had consistently lower patulin concentrations.
FAO, 2003, Manual on the application of the HACCP system in the prevention and control of mycotoxins [online]. Product quality depends not only on the capabilities and safety of the process and preventive measures such as GMP, HACCP, maintenance, etc.
Hygienic Design
- Regulations, standards and guidelines
- Building design
- Equipment design
- Equipment installation and integration
Insulation should be placed on the side of the wall that is in the area where hygiene requirements are lower. And the distance between equipment and the civil structure should be sufficient for cleaning and inspection.
Cleaning Validation
- Status evaluation
- Risk analysis
- Cleaning process studies
- Assessment and implementation
To select equipment and appropriate cleaning procedures to be validated, and to determine acceptance criteria and analytical methods, products (composition), procedures (possible risks), equipment (construction) and cleaning procedures (cleaning agents) must first be evaluated. Validation procedures should be performed with a minimum of 3 successful consecutive applications of the cleaning procedure.
Conclusion
A Change Control SOP should be available to record any changes to product, process, equipment, cleaning and validation procedures. Revalidation should be carried out a) periodically and b) in case of any change in the product, equipment, cleaning procedure, etc., it should be decided whether the change will affect the cleaning procedure and if therefore the cleaning procedure should be is reassessed. : Intervals of periodic reassessments should be determined prior to approval.
The outer cover should also inform the consumer about the product and the design should promote the product. Packaging technologies combine a wide range of techniques and materials with two basic goals: to protect the product and to display the items for sale.
Food Packaging Techniques
- Vacuum packaging
- Moderate vacuum packaging
- Active packaging
- Edible coatings
- Modified atmosphere packaging
- Aseptic packaging
In gas packaging for retail trade with raw meat, e.g. a high oxygen concentration, even 80%, to prolong the duration of oxymyoglobin, which gives a cherry red color to the meat surface. The technology called "clean room" must drastically reduce the number of microorganisms in the areas where food is produced, sliced or packaged, in order to increase safety and stability.
Packaging Systems
- Horizontal form-fill-seal machines for rigid and semi-rigid packages (so-called deep-draw machines)
- Horizontal and vertical form-sill-seal machines for flexible “pillow-pack” pouches (so-called flow-pack
- Vacuum chambers machines
- Gemella packaging system
- Fibrelam system
- Bag-in-carton systems
- Bag-in-box system
- Walki-vent system
- Flavaloc
The machine inserts two snorkels into the top of the bag, creates a vacuum and gas flame (Figure 1). The package is claimed to solve many of the problems, such as deterioration of the cap material during shipping and handling, commonly associated with the use of conventional gas packages containing a thermoformed tray and a heat-sealed cap. material.
Packaging Materials and Food Applications
- The gas barrier properties needed
- Mechanical strength
- Integrity of sealing
- Type of package
- Fogging
- Microwaveability
- Biodegradability and recyclability
- Thermal and mechanical properties
- Compostability
- Manufacturing of food biobased materials
- Biobased food packaging materials
Adequate seal integrity is important to maintain an adequate package atmosphere. In particular, development is currently focused on bio-based materials that must be able to mimic the water vapor barriers of conventional materials known today.
Safety Aspects on Active and Modified Atmosphere Packaging
- General packaging safety considerations
- Conventional packaging safety considerations
- Unconventional packaging safety considerations
New concerns about migration have recently arisen due to the use of recycled materials or refillable containers for food and beverage packaging (Begley and Hollifield, 1993). In some cases the use of functional barriers will be necessary to prevent migration of the active components (Hotchkiss, 1995).
Prerequisite Programmes
- Building location and environment
- Sanitary design and engineering
- Good manufacture practices
- Cleaning and sanitation
- Receiving, storage and shipping control
- Pest control
- Waste control
- Chemical control
- Supplier control
- Trace and recall
- Equipment calibration
Production facilities must be designed to allow thorough control of the entire process (Zerfiridis and Litopoulou-Tzanetaki, 1988). Personnel responsible for the use and supervision of cleaning and hygiene procedures must be trained.
Preliminary Tasks
- Assembling the HACCP team
- Description of the product
- Description of the intended use and end user
- Developing the process flow diagram
- Verifying the accuracy of the process flow diagram
The relative humidity of the plant where feta cheese is matured should be 95-100%. Inspection of manufacturing processes is essential for validating how clearly the flow diagram describes the process.
Principles of HACCP
- Hazard analysis
- Determination of critical control points
- Establishment of critical limits
- Establishment of monitoring procedures
- Establishment of corrective actions
- Establishment of record keeping and documentation procedures
- Establishment of verification procedures
Personnel responsible for corrective actions must be well informed about the HACCP plan and have a thorough understanding of the production process. The HACCP team is responsible for the development, establishment and implementation of the verification procedures and activities as well as the timing.
Concluding Remarks
Genetically Modified Organisms
- GMO: new biotechnology products
Herbicide-tolerant pasture crops, such as subterranean clover, allow farmers to control broadleaf pasture weeds earlier in the growing season with low levels of herbicide. There is a fear that uncontrolled introduction of genetically modified organisms could cause unwanted effects on ecological or genetic relationships in some communities or possible harm to some consumers in the food chain.
Familiarity and Substantial Equivalence
However, some aspects of the steps in the safety assessment process could be improved to keep up with developments in genetic modification technology. Substantial equivalence confirms that the objective of the assessment is not to establish absolute safety, but to examine whether a genetically modified food is as safe as its traditional comparable food, if such exists.
Novel Foods Based on GMOS
- Principles and practice of GMOs and novel food safety assessment
- Risk assessment
- Risk management
- Risk communication
The process involves reviewing alternatives and selecting the most appropriate regulatory action based on the findings of the risk assessment. The Biosafety Clearinghouse will serve as a vehicle through which information relevant to the implementation of the Protocol is made available.
Ethical Questions Related to Safety Issues
- Modified foods on market
MON 810, A Case Study on Genetically Modified Maize
The behavior and properties of MON 810 have been studied in numerous field trials in the USA and Europe since 1992 (Essential Bisafety, 2001). Observation and field experiments have shown that the mode and propagation of MON 810 is typical of other maize varieties (Essential Biosafety, 2002).
Future Trends
An important element in the determination of substantial equivalence is the effect of compositional comparison, where a comparison of critical components can be carried out at the level of the food source (i.e. species) or the specific food product (FAO, 1996). The data for the non-modified comparator can be the natural varieties published in the literature for commercial varieties or those measured levels in parental or other edible varieties of the species.
Nutritional strategies targeting the beneficial modulation of the intestinal microflora in relation to food safety: the role of probiotics and prebiotics. In this sense, the implementation of the HACCP (Hazard Analysis Critical Control Point) concept, backed by good manufacturing practice (GMP) and the use of rapid detection methods, improves the safety assurance of food by reducing the risk of microbial spread from farm to fork ( Jay, 1992).
Intestinal Microflora Composition and Metabolic Activities
For example, there is increasing evidence that dietary modification using functional foods (e.g. probiotics and prebiotics) could benefit the host by inducing a health-promoting change in the composition and activities of the intestinal microflora (Salminen et al., 1998). There is evidence that the composition and activities of the gastrointestinal microflora can have beneficial and pathogenic consequences for the host.
Probiotics
- Selection criteria for probiotics
- Legislation, safety considerations and claims for the use of probiotics in foods
- Health benefits – established effects
However, it should be noted that documented associations between systemic infections and probiotic consumption are few and have all occurred in patients with serious underlying health conditions such as immunocompromised individuals (FAO/WHO, 2002; Saarela et al., 2002 ). FAO/WHO (2002) recommended that specific health claims, such as claims of enhanced activity and/or disease prevention, on foods containing probiotics be allowed only in cases where sufficient scientific evidence is available.
Prebiotics: Role as Bioactive Nutrients
- Origin and manufacturing processes
- Physicochemical characteristics and properties
- Legislation and safety issues linked with the use of prebiotics in foods
- Physiological effects and health benefits
- Future prebiotics with enhanced functionality
This in turn results in the development of different profiles of saccharolytic activity along the colon (Olano-Martin et al., 2000). Research in humans and animals shows that the consumption of prebiotics stimulates and increases the growth of probiotic bacteria in the intestinal microflora (Van Loo et al., 1999, Bouhnik et al., 1999).
Functional Foods: Probiotic and Prebiotic Applications in Foods
Gibson, G.R., Beauty, E.R., Wang, X., and Cummings, J.H., 1995, Selective stimulation of bifidobacteria in the human colon by oligofructose and inulin. Peterson, J.A., Patton, S. and Hamosh, M., 1998, Human milk fat globule glycoproteins in the protection of the breastfed infant against infection.
Why Fermented Products?
Christian Hansen was the first to isolate and propagate special yeast for use in breweries. During the same period, microbial enzymes were also developed such as proteases, amylases and invertases (Mongensen et al., 2002).
Bacteria
- Advantages for health and safety
- Starter cultures
- Genetic engineering of species
The acid formed during the fermentation of carbohydrates can help lower the pH of the stomach. Reduction of pH due to the production of organic acids, lactic acid, acetic acid, etc.
Starter Culture Production
- Introduction
- Starter cultures for wine
- Starter cultures for vegetables
- Starter culture for bread
- Starter culture for meat
- Starter culture for dairy products
- Composition of starter cultures
- Manufacture of starter cultures
Starter cultures are used either from a bulk starter container or inoculated directly into the mixture. The medium used for growth of the bulk starter is typically UHT milk (sterilized by short-term high heat treatment).
Yeasts
- Desired properties of fuel ethanol – producing yeasts
Chemical tolerance, resistance to bread preservatives and the presence of sodium chloride. Bioethanol production in countries with large agricultural areas, such as Brazil, South Africa, Canada and the USA, intensive studies are being carried out on the production of ethanol from carbohydrates such as sucrose, starch and cellulose, which not yet competitive with oil, but biotechnology and bioprocess engineering may improve future competitiveness. Candida Shehatae stipiti and Pichia were the most successful yeasts studied, although the presence of inhibitory chemicals in the hydrolysates limited their growth and metabolic activities.
Inventory of Microorganism with a Documented History of use in Food
- Value added products from the microorganisms
- Some fermentation products of high value added from yeasts
- Some fermentation products of high value added from bacteria
First was the development of the hybridoma technique for the production of monoclonal antibodies, which was of interest mainly in the field of medical diagnostics. At the same time for the production of products with added value, it seems evident that microorganisms have become a very important economic asset.
Microbial Relationships in Food Ecosystems
The Centers for Disease Control and Prevention (CDC) in the United States estimates that 76 million people contract foodborne illnesses each year in this country, resulting in 325,000 hospitalizations and more than 5,000 deaths. The most common symptoms of foodborne illness are diarrhea, abdominal cramps, vomiting, headache or muscle pain, and fever.
Microbial Interactions – General Considerations
- Mutualism
- Commensalism
- Antagonism
- Microbial interactions – selected case studies
The ability (of a microorganism) to live on the external or internal surfaces of the body without causing disease. During cheesemaking and ripening, a number of interactions occur between individual components of the cheese microflora (Beresford et al., 2001).
