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Re-assessment of food safety risks in cereals processing

06 March 20187 min reading

“Hygienic design of food processing equipment, in general, is one of the major prerequisites for preventing food contamination as well as for maintaining product quality and increasing production efficiency. Carefully designed hygienic equipment helps protect the final consumer against food-borne hazards and also offers tangible benefits to food manufacturers and processors. Not only does it reduce the risk of contamination - and, thereby, minimize the possibility of costly product recalls -, but it also maintains product quality, increases productivity, and contributes to sustainability”.

Edyta MARGAS

Dr. Edyta MARGAS

Food and Feed Safety Leader Bühler AG, Switzerland

The food safety risks associated with non-ready-to-eat, cereal-based products such as flours or raw dry pasta have traditionally been considered to be relatively low. These products are dry and therefore have a water activity (aw) value of less than 0.85, which inhibits the growth of food-borne pathogens. Additionally, such foods are intended to be further processed or cooked before consumption. This means that some of the potential hazards such as foreign matter will be further eliminated or, in the case of microorganisms, inactivated. But low risk does not mean no risk. A number of well-documented outbreaks of food-borne illness have shown that dry foods may act as a vehicle for pathogenic bacteria, especially Salmonella, which is responsible for around 75% of all outbreaks (Beuchat et al., 2013). Over the past two years (2016 and 2017), the flour industry has suffered major contamination incidents involving microorganisms such as Salmonella and E.coli. Even though flour is intended for further cooking, the pathogens might cause illness if raw cookie dough is consumed or they can be presumably transferred to other foods in the consumers’ kitchens. In addition, in the past year (February 2017 – February 2018), over 280 incidents related to flour contamination were reported. Most of them were caused by the presence of undesirable microorganisms (Bühler Food Safety Intelligence, safefood.ai).

These incidents shed new light on the food safety standards that such foods must fulfill. The food industry and the scientific community are now paying closer attention to the microbiological safety of dry products. A vast amount of knowledge on Salmonella survival exists in the factory environment, which can last for months (or even years), or Salmonella may survive industrial processing in low-aw foods (Margas, 2016). Salmonella are among the most challenging microorganisms because many strains survive drying. In addition, they are relatively heat-resistant at low aw values, requiring severe thermal treatment for inactivation. Finally, microorganisms in general are heterogeneously distributed in dry materials and, for that reason, end-product testing is of limited value as a yardstick for verifying microbial product safety. These are among the major reasons why Bühler launched its Food Safety Initiative. The initiative focuses on educating employees, developing technologies to mitigate food safety risks, building knowledge, and working with credible partners and customers on the topics of food safety and hygienic design.

On the other hand, stricter food safety regulations are now being enforced. In this context, the U.S. Food Safety Modernization Act (FSMA, first part) went into effect in September 2016. The law enacted in 2011 has been called the most sweeping reform of U.S. food safety laws in more than 70 years. The U.S. as well as European law aims at ensuring safe food supplies by adopting preventive and risk-based approaches to food safety rather than responding to problems after they occur.

This means that a food safety plan should be implemented also for non-ready-to-eat products which includes a combination of measures to prevent the introduction, growth and transfer of pathogens within the factory environment. It also requires identification of the points where appropriate bacterial inactivation methods should be implemented within the whole value chain (Figure 1). Recently, a shift of the microbial reduction stage to the beginning of the value chain has been observed. Bühler has been working actively on the evaluation of thermal flour treatment methods as well as non-thermal technologies to decontaminate raw materials. Furthermore, the company has developed technologies to validate, monitor, and adequately record data gathered in microbial reduction steps. Implementation of such early inactivation processes alone cannot solve the problem. It would also mean that hygienic levels must be increased and more hygienic processing must be ensured directly after such a step. Such a step would greatly change the whole cereal processing industry, since the infrastructure of many existing factories would have to be modified in order to build barriers preventing the entry or transfer of bacteria, for instance by uncontrolled air flows or personnel and product movements. Furthermore, the equipment after the microbial reduction step would have to be based on an adequate hygienic design.

Hygienic design of food processing equipment, in general, is one of the major prerequisites for preventing food contamination as well as for maintaining product quality and increasing production efficiency. Carefully designed hygienic equipment helps protect the final consumer against food-borne hazards and also offers tangible benefits to food manufacturers and processors. Not only does it reduce the risk of contamination – and, thereby, minimize the possibility of costly product recalls –, but it also maintains product quality, increases productivity, and contributes to sustainability. Less time and fewer people are needed for cleaning and changeovers, and less product is wasted. Therefore, some hygienic design principles such as easy access allowing effective and efficient cleaning are also key factors in equipment used for handling raw products such as flour or pasta. Bühler has recognized the key role that is played by machinery design and has been applying best practice in the design and engineering of its own equipment to offer customers state-of-the-art technologies. Bühler’s dedication to this topic is also reflected in its active involvement in the European Hygienic Engineering Group (EHEDG) and in its contributions to defining hygienic design guidelines. Several examples of hygienic solutions dedicated to raw materials handling exist. As an example, Bühler has developed the micro-differential proportioning scale (MSDF-A, Figure 2) or scales offering excellent access for cleaning, high cleaning efficiency, and certified materials in contact with the food. Furthermore, innovative hygienic design solutions have been implemented in its ready-to-eat cereals equipment portfolio such as the flaking mill (Figure 3) or the ready-to-eat cereals dryer. The focus on new developments is also on enabling easier detection of contamination by foreign matter such as plastics and rubber. These materials incorporated in new machines are often blue and metal-detectable. Furthermore, the innovative approach to foreign matter removal includes the use of optical sorting for short pasta forms, which is one of many applications of Sortex.

Pathogens or foreign matter are not the only hazards associated with raw cereals products. The presence of mycotoxins in such products is gaining more attention. This is mainly due to the warming of the climate and the globalization of the supply chain. Mycotoxins are very hard to deactivate. Therefore, the only effective way to reduce mycotoxin levels is to remove the contaminated fraction. This can be done by implementing a series of cleaning methods such as aspiration, size separation, density separation, and ultimately techniques such as optical sorting.

The re-assessment of all these existing hazards in conjunction with continuous improvements and innovations are key to ensuring food safety. Often, the implementation of the best food safety solutions requires collaboration with technology suppliers, food producers, and scientific partners. But hygienic design and new technologies are just one aspect contributing to the production of safe food. Another aspect that stands to revolutionize this part of the food industry in the near future is the progress being made in the field of digitalization. Even now, many solutions exist at Bühler for accurate product traceability, predictive equipment maintenance, improved machinery performance, as well as monitoring of some key equipment parameters such as temperature, humidity, moisture, etc. The analysis of such data together with the use of additional information will make it easier to evaluate food safety risks and to choose the best possible measures to control them.

References Beuchat, L.R. ve diğ. (2013) Low-water activity foods: Increased concern as vehicles of foodborne pathogens. Journal of Food Protection 76(1): 150–172.

Warren, B. (2012). HACCP and the Critical Role of Prerequisite Programs. IAFP’s European Symposium on Food Safety, 21–23 May 2012, Warsaw, Poland.

Margas, E. (2016). Doktora tezi: The survival and control of Salmonella in low-aw foods environments. The University of Nottingham, UK.

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