Food safety: validate your pathogen destruction processes once and for all

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The risk of food poisoning, usually caused by food-borne pathogenic microorganisms, is a constant fear for the food industry – and unacceptable to consumers. Technology for killing pathogenic microorganisms are now widespread but controls used by the food industry do not guarantee their effectiveness. This is because they are mainly based on sampling finished products.  It is necessary to establish preventive methods with validated effective pathogen destruction protocols. The solution of surrogate bacteria is a welcome guarantee.

 Food poisoning is still frequent worldwide and common in western countries. However, in other parts of the world, it is a significant issue for public health and an economic challenge. Globally, the WHO estimates that 600 million people, almost one in ten people worldwide, suffer from food poisoning each year – causing 420,000 deaths (source). While mortality from food poisoning in Europe is lower (5,000 according to the WHO), the risk is still high despite advances and precautions taken by the food industry. Risk of food poisoning is a constant fear in the food industry and unacceptable to consumers.

It is estimated that 80% of food poisoning is caused by pathogenic microorganisms: Escherichia coli 0157:H7, Salmonella, staphylococci etc. come from their environment such as soil or plants or from animals or humans (waste, skin, mucus. etc.). Problems persist in finished products, despite regular controls including self-audits by professionals and regular checks by official bodies*, as well as training for food industry professionals in hygiene regulations. (*France: DGAL and DGCCRF)

Technologies for pathogen destruction are widely used, but testing methods used in the food industry do not guarantee their effectiveness. This is because they are mainly based on finished product sampling. The diversity of pathogens in food products is one of the main problems. As a result, the sampling process only confirms that the samples collected are pathogen-free, while unsampled products may be contaminated. A consistent preventive method that can be reproduced is required to validate destruction protocols.

How to validate the effectiveness of your pathogen destruction processes?

A variety of - unreliable - methods exist

Sterilisation, pasteurisation, cleaning processes, extrusion, heating, etc. How to validate the effectiveness of your pathogen destruction processes to ensure food safety? Sampling methods do not cover the whole quantity of finished product, but several preventive methods exist:

• use of documented data
• mathematical modelling
• experimental laboratory tests

These methods are controlled but limited to a theoretical or laboratory perspective, far from the factory floor. How well do the results represent the reality of your production line? Of your industrial processes? Of your product?

What about testing in real conditions?

Industrial-scale experimental tests can be conducted to fill the gap. It is impossible and unimaginable to voluntarily introduce pathogens into your factory. That’s why Novolyze developed surrogate bacteria: They are harmless bacteria that mimic the behaviour of pathogenic bacteria. They can be used directly in your factory to simulate contamination and test the effectiveness of your destruction processes.

Surrogates are recognised by the Codex Alimentarius as a valid control method.  Highly characterised, tested widely, and in some cases featured in scientific publications, surrogate bacteria are absolutely harmless, making them extremely safe for use in real conditions.

Example: cocoa

Roasting is one of the most widely used technologies in the cocoa sector. The aim of roasting is to develop the organoleptic qualities of cocoa, but it also kills pathogens, particularly salmonella.  In roasting, high temperatures are applied to cocoa beans or chips for several minutes, generating stress that kills bacteria. But how can a company verify the effectiveness of their cocoa roasting process and ensure that the time and temperature is sufficient to destroy salmonella?

In the cocoa sector, the most common goal is to destroy 6-log or 99.9999% of salmonella. Novolyze has launched a surrogate that mimics the behaviour of salmonella under thermal stress. The cocoa is first inoculated with a very high concentration of the surrogate, about 100 million bacteria per gram of cocoa. It is then placed in the roaster to be tested, directly on the factory floor. After the standard roasting process, inoculated cocoa samples are collected and analysed. The test is positive if, after roasting, there remain 100 surrogate cells per gram or less:  roasting has destroyed 99.9999% of the bacteria. Tests are usually repeated two to three times to confirm the results. 

Dry, industrial and stabilised germ models: many advantages

Using dry surrogate bacteria rather than conventional liquid inoculation has many advantages:

• They can be adapted to a wide range of products, without changing the physicochemical properties. This is particularly the case for dry products, such as nuts, spices, flour, cocoa, milk powder, pet food, breakfast cereals, extruded vegetable proteins and biscuits
• They can be directly incorporated in a food matrix without prior enrichment
• Initial concentrations with thermal resistance are guaranteed, making it more suited to the target pathogen than liquid surrogates
• Inoculation is denser which means the product has a higher level of inoculation than when using the liquid method
• Finally, they are more stable and have a longer life cycle of several months

Other applications...

In addition to validating pathogen destruction processes, surrogates can also be used for a wide range of food safety applications as part of a HACCP approach:

• Testing new technologies or processes to validate the quality of the finished product in a pilot line before investment
• Optimising process scale, fine-tuning control of organoleptic quality in real conditions
• Optimisation also leads to increased machine productivity thanks to reduced downtime
• Optimisation and validation of cleaning and disinfection protocols for the production environment such as floors and surfaces

Keywords

Food safety, pathogens, food poisoning, validation, food industry

Further reading

• https://www.novolyze.com/en/
• This French Biotech is Developing Kits to Stop Food Poisoning 
• Novolyze raises €2.2m investment to fight risk of foodborne illnesses 
• Novolyze facilite la détection des risques d'infection alimentaire 
• Les réglementations dans l’agroalimentaire : en faire une force pour innover