Managing your steam system quality to meet food safety requirements

Spirax-Sarco is a British manufacturer of steam management systems it’s headquartered in Cheltenham, England. It is listed on the London Stock Exchange and is a constituent of the FTSE 100 Index. Our team is passionate about steam and Sustainability has now become a business imperative and industry to step up to lead the charge towards a more sustainable future.Spirax Sarco is multi-national engineering group whose world-leading industrial and commercial steam systems, advanced electric thermal solutions, pumps, and fluid path equipment can be found in industrial and commercial settings worldwide.

 

We can advise on and help implement cost-saving, energy reduction tactics to cut down on your energy usage, whilst considering any self-generation technology and finance option available that will help reduce your carbon emissions and meet evolving legislative compliance criteria.

 

Steam is well known for delivering safe, sustainable, and efficient energy. Today’s consumers are more conscious of food safety than ever. Together with the regulators and the major retailers Spirax Sarco will add value in underwriting steam related disputes in industry. We all know that are placing food production under increasing scrutiny. Anything that introduces a risk of contamination is unacceptable and that includes the steam used directly in the production process or via sterilisation.

 

Steam is prime carrier of heat for all types of industries, ranging from food and beverage through to dairy. Steam is used for heating of processes, sterilisation of products, equipment and for normal working conditions. For many of these applications normal factory black steam contains various quantities of uncontrolled boiler feedwater chemicals and traces of pipe scales and other debris. With the changing marketplace and forced regulatory legislation coming on board it’s not acceptable to use factory steam on certain application as comprehensive enlightened below.

 

With few standards for steam quality in the food and beverage sector, manufacturers should be considering the use of clean steam as standard practice to eliminate any contamination risk. Clean steam is providing the answer for many applications in the food and beverage where tougher standards and public concern over recent food and health scares have made steam quality and purity of paramount importance.

 

Spirax Sarco can strategise and recognise how best to support you and your teams in the introduction and raising the awareness of Steam Quality as part of Food Safety. Clean Steam generation is the only way to ensure and guarantee consistently that the Steam is free from any contaminants and it’s the only method to achieve uniformity according to HACCP. We need to honest with ourselves that using Filtered / Culinary steam is not clean steam and still possess the risk of volatiles entering the process, yes it does minimise the risk but does not eliminate it altogether.

 

There are four grades of steam commonly used in the industry today, from basic plant steam, through to filtered (culinary) steam, clean steam, and pure steam. While plant steam meets the demand for heat transfer applications in many industries, some food companies use filtered steam, with even more now turning to clean steam , where tougher standards and public concerns over recent food and health scares. Clean steam is providing the answer for many applications in the food and beverage sectors that has taken steam quality and purity of paramount importance.

 

Steam when in direct contact either through Sterilisation or directly onto the products MUST BE considered AS INGREDIENT because it introduces unwanted odours, taste and even taint to the final process. Food and beverage manufacturers are legally bound to ensure the quality of the final product by identifying potential hazards and controlling them, typically by using a HACCP (Hazard Analysis Critical Control Points) approach. The current lack of legislation or guidance governing the quality and purity of steam means that manufacturers should therefore be vigilant in ensuring suitable controls are established and adhered to where steam is in direct contact with the product or process.

 

WHY Steam as an Ingredient?

 Food business operators shall put in place, implement, and maintain a permanent procedure or procedures based on the HACCP principles.
Steam used directly in contact with food is not to contain any substance that presents a hazard to health or is likely to contaminate the food.
 

A recommended approach to applying HACCP to name a few involves the following steps: Each one requires of these steps shown below requires the HACCP approach to ensure Food Safety

 

1.      Determine quality of raw boiler feed water

2.      Determine levels and types of dosing chemicals

3.      Identify other potential sources of contamination arising from the use of an inappropriate grade of steam

4.      Assess any risks associated with ‘product’ contamination, for example potential health hazards

5.      Devise and adopt an effective steam quality testing regime

6.      Adopt best practice in the design, maintenance and testing of the steam system to ensure that the correct quality of steam reaches the process.

7.      Regular Steam Traps surveys

8.      Regular checks and cleaning of Dead legs, Crevices and Dirt Pocket to include Condensate dirt pockets

9.      Ongoing Boiler management control

10.    Inline Steam Quality Testing

 

This means manufacturers should ensure suitable controls are established and adhered to for all possible hazards. Within a HACCP context, steam quality and safety could be described as a HACCP prerequisite or, if the steam is added directly into the product, as a stage in the food production process.

 

Purity Qualities of Steam                            Physical Qualities of steam

 

·        pH                                                                 1:  Non condensable gas content          

·        Chloride                                                                    < 3.5% by volume in condensate

·        Conductivity                                             2:  Steam Dryness Value

·        Hardness                                                                 > 0.95 for metal loads, other loads

·        Ammonium                                              3:  Superheat

·        Calcium                                                             < 25°C when expanded to atmospheric pressure

·        Sulphates

·        Nitrates

·        and others…

 

Contaminants can be chemical, physical, or microbiological.

 

Steam Is divided into two Quality procedures

Steam quality - Quality – is the steam attributes: dryness, non-Condensable, superheat
Steam quality is a term used regarding steam systems. In this context the word quality commonly refers only to the amount of water in the steam and not any other contaminants. A more correct term is dryness fraction.

Steam purity - Purity – is the chemical and microbial attributes of the condensate
Steam purity is a quantitative measure of the dissolved solids, volatiles or other particles in the vapour that may remain in the steam following primary separation in the boiler.
 

Filtered steam, which is often referred to as culinary steam, is essentially plant steam passed through a fine, stainless-steel filter – generally a 5-micron element which removes 95% of all particles larger than 2 microns in size. While filtered steam is generally regarded as the minimum grade for food and beverage processing, it is vital to note that the filtration process only eliminates rust, pipe scale, and other corrosion-based particulates from finding their way into the product. It is not designed to remove chemicals or carry over from the steam cause by the boiler and this can be inconsistence steam changes every second. A pre-filter (typically 25 microns) is placed upstream of any 5-micron filter to prevent rapid blinding (blocking) of the main culinary filter. Note that water treatment, boiler carryover and cross contamination still pose a risk, because the filter will not remove all the potential contaminants. In fact, the 3-A Practice specifically stipulates that boilers should be ‘operated in such a manner as to prevent foaming, priming, carryover, and excessive entrainment of boiler water into the steam’. Dryness Fraction = Mass of steam/ (Mass of steam + entrained water)

The consequence of this limitation is that manufacturers injecting filtered steam into their product remain susceptible to contamination from chemicals used to treat the boiler feedwater or from various cross contamination points within the plant. Although these contaminants may not be as visible as the particulates generally captured by a filter, they can affect the taste and taint of the product in question, which may impact quality control and downstream supply chain activity.

 

Food & Beverage Manufactures trend towards Filtered but clean steam is undergoing the biggest shift. This is partly because manufacturers want to avoid quality issues, expensive product wastage and even product recalls with the associated damage to their reputation.

 

Clean steam is different because it relies on a secondary generator and tightly controlled feed water quality to eliminate many of the potential issues already outlined. It’s critical to start with the right water quality. Raw water is not adequate and will require pre-treatment. Reverse osmosis (RO), deionised/demineralised (DI) and continuous electrode ionised (CEDI) water are all good possibilities for generating Chemical free steam. They all remove the need for chemical treatment by removing most of the particulates, inorganics, and dissolved solids at the pre-treatment stage. The risk of water treatment chemical contamination is therefore eliminated when using clean steam.

 

In addition to the quality/purity of the clean steam leaving the generator, there are other factors that should be considered when installing a clean steam system. Clean steam is very aggressive, so grade 316 or 316L stainless steel is typically used on contact surfaces throughout the system to protect against rouging. In addition, even though the temperature of the steam will keep most bacteria at bay, the surface finish of equipment should minimise any crevices that could encourage microbial growth. Similarly, a clean steam distribution system should be designed to good engineering practices.

 

Clean steam is often used in applications such as sterilisation and direct steam injection not only to eliminate contaminants, but also to ensure the quality control of critical attributes such as dryness, superheat, and production of non-condensable gases, all of which could adversely affect the process and equipment.

 

Using unsuitable steam could cause serious health risks to consumers. Some potential contamination risks can be filtered out, but to make it fit for consumption, direct steam injection should be from a dedicated clean steam source.

 

The key to food manufacturers eliminating the risk of contamination is a more widespread use of clean steam. In contrast to both plant and filtered / Culinary grades, clean steam is used as standard in a range of quality-critical processes. Rather than relying on a filtration process to extract particulates, its production utilises a secondary steam generator with the ability to control feedwater quality. Clean steam requires the use of stainless-steel pipework and components that eliminate the potential for corrosion of steam traps, valves, and pipeline equipment made from traditional carbon steel materials.

High chloride cause stress corrosion. When chlorides are present at an unacceptable level, chloride stress cracking can also occur. Corrosion typically occurs in the parts of the boiler that are heated the most, where high temperatures and cracking in the metals accelerate the breakdown of the materials

 

Aside from the clear benefits clean steam can bring in terms of compliance, food technologists and quality managers can also be assured of its ability to deliver consistent quality and flavour. With greater traceability, this is a real benefit to major retailers, who we anticipate will also become much more aware of the effects filtered steam can have on the colour and taste of their products. Using clean steam can help these organisations to reap the benefits of greater compliance with stringent food safety standards, thereby meeting their legal obligations, and enhancing their overall process productivity.

 

Other Issues that need to be considered in a clean Steam system:

 

Poor hygienic design of food process equipment and inferior build quality can affect the quality and microbiological safety of your product. All surfaces in contact with the food must be cleanable, since equipment which is difficult to clean will require more aggressive chemicals and longer cleaning cycles, resulting in higher costs, lost production time and increased effluent.
Hygienic and aseptic conditions are achieved by a variety of procedures ranging from manual strip down and cleaning of component parts to Clean In Place (CIP). For a CIP system to clean effectively the fluids must be at the correct temperature, velocity, and pressure to ensure product debris is dislodged.
Materials used in the construction of food processing equipment must be inert to both the product and cleaning chemicals whilst also being corrosion resistant and nontoxic, manufactures from AISI- 316 and 316L stainless steel.
Operational reliability and the trouble-free service provided by our process equipment results from the correct selection of high-quality specialized lubricants. To fulfil international food processing safety requirements, we use USDA authorized ‘food grade’ lubricants. The use of unspecified lubricants can seriously affect valve performance due to possible elastomer distortion and swelling and this is particularly important in the case of EPDM elastomer types as these are extremely sensitive to contact with unsuitable lubricants.
Surface roughness can also have a significant influence on cleanability. In general, the greater the surface roughness, the longer the cleaning time required.
The exterior and interior of all food contact equipment must be self-draining and easily cleanable, with the designs to incorporate and ensure there are minimal threads, pits, crevices or sharp edges in contact with the product.
 

Some applicable legislation guidance’s that help encourage the use of Clean Steam generation:

 

UK/Europe: EC No. 852/2004
Steam used directly in contact with food is not to contain any substance that presents a hazard to health or is likely to contaminate the food’
FDA Regulation – 21CFR 173.310
Boiler water additives may be safely used in the preparation of steam that will contact food, under the following conditions:
The amount of additive is not more than that required for its functional purpose, and the amount of steam in contact with food does not exceed that required to produce the intended effect in or on the food.”
EC1935/2004… EU regulations - Requirements for Food Contact Materials (FCM) varied significantly from country to country.
EC1935 sets out the general principles of safety and inertness for all Food Contact Materials (FCMs) where steam should be considered for applications when in direct contact
In 2004, the European Commission decided to establish a single piece of legislation to standardise it within the EU. They particularly focused on EC1935/2004, which controls the requirements on materials for food contact applications.
The reasoning behind it is that under typical or expected conditions of use, they don’t transfer their elements to food in amounts that could:
Transfer any constituents to food in quantities that could danger human health
Cause an unacceptable change in the composition of the food (taste, odour)
Bring about unacceptable change in the composition of the food, or adversely impact the organoleptic properties of the food
HACCP: International Standard Operating Principle: Hazard Analysis Critical Control Point (HACCP)
 

EC1935/2204 gives the peace of mind and ensuring that all food process contact material are food safe, steam passes through such materials, and classified as an ingredient therefore to ensure its not contaminated we must study the steam generation system by applying HACCP this will make industries consent that shifting the outcome to Clean Steam generation from boiler to end process is the solution to guarantee Food safety.


If you’re looking for more information on Food safety in respect to steam quality, Spirax Sarco is the vendor who can provide guidance on best practice for steam systems, advice on steam quality testing and offering training is a good place to start.


Best of all however, clean steam has the potential to make a real impact on what matters most to the consumer – the taste of the product. Spirax Sarco is a world leader in steam and energy solutions. You can contact us for advice on which grade of steam is right for your process.