Is There a Risk of Food Contamination from Natural Gas Leaks and Mercaptan?

We were coming up with a scenario for a mock recall, and a potential one was our forklift accidently clipping the overhead heater gas line, causing a leak.

However, I can't find any reference to whether natural gas, and specifically its added mercaptans, would contaminate the product around the leak.

We are a dry ingredient blender, so the potential products are ingredients and dry blended powders, stuff that somewhat readily absorbs odors.

Anyone have any experience with this as to whether this would be a contamination concern? 

Hi Spicy,

:surprise:   An interesting scenario! 

First of all the product would be within your control and so why would there need to be a recall? mock or not.

For me this is more a crisis management scenario where you want to evacuate so that no one dies of asphyxiation or an explosion. The line should then be isolated and the area ventilated.

Deal with the product afterwards, the actions above should be quick and so I don’t see how there would be serious exposure of the product until it was open but you have it in your control and you can assess the risk and sample accordingly.

Kind regards,

Tony

Hi Tony,

You are correct, it is actually for our crisis management, I just had mock recall on the brain as we were dealing with that this week too.

I do appreciate your suggestions, and that part is understood.

I was just curious specifically on the natural gas and/or mercaptans and their potential to contaminate the product by direct or indirect exposure to the escaping natural gas as I can't find any reference in literature or even from the local gas company itself to it contaminating food or not.

In our experience the multiwalled pinch bottom heat seals we use as well as supplier valve bags are not great at odor control or absorption, with poly plastic lined boxes being better but not 100%, either.

I would assume a bag of flour directly exposed (ie leak directly above and onto it) to a venting gas line would pick up at least the mercaptan odor, but have not seen any potential risk to the product mentioned anywhere.

But yes it would be a given we would have to sample and evaluate to ensure everything was fine both from a safety and a quality concern should it ever happen (knock wood it never does, thankfully everyone is up to date on their forklift course lol).

Thanks for your above response, it was appreciated!

Its a brilliant idea for a mock crisis that I admit to now having stolen

my brief research shows that it bonds well with protein (so gluten in your example )

My finished good is particularly sensitive to odour absorption, so while my product may not be "unsafe" it may still not meet the quite literal sniff test

Thank you Scampi.

Very interesting dilemma. I found this lab protocol for testing biological samples for mercaptan.

If I was in your shoes, I would send this to a local lab and ask if they are capable of one of the protocols listed.

https://www.atsdr.cd...es/tp139-c6.pdf

Once I found a capable lab, I would do the following:

• Obtain 2 separate samples of unaffected product as your control values. 
• Collect samples in ascending distance from the leak.
• Discard anything with mercaptan levels above the control values.
• Extrapolate the data to show where contamination ends. Discard anything within the circle.

The lab procedures look pretty simple. Since mercaptan is water-soluble, I would expect any lab with a GC to be able to test for this. 

Thank you AltonBrown.

I like the scenario too.  From what I'm seeing in my mind, a gas leak would trigger an emergency evacuation, full stop.  Then you've got to deal with the shutdown period after you had to allow firefighters and emergency contractors to walk your production area to contain the emergency.  Everything open in your production area is now 100% deviated due to the gas exposure, non-GMP personnel exposure, etc., so at re-start of operations you'd be accounting for everything exposed and writing a discard form for all of it (and you'd have to consider ramifications for any sealed product that was staged to be processed, something you can determine with investigation namely for odor).  Then you'd be documenting a full sanitation of the equipment and area before returning to active production.

My old spice plant had a real crisis scenario play out during their SQF audit.  Day 2, they all walk in that morning to find the city back flow preventers had failed and all toilets adjacent to the production area were overflowing (including into the production area).  Apparently a lot.  So they didn't fire up production and had doors open with plumbers and contractors all over trying to stem the flow.  The only finding they took during this was that the production manager failed to document and communicate clearly that the plant was shut down and would be shut down until this was resolved satisfactory.  I share just to say that one step of you documenting this crisis is to show when someone made the decision to suspend operations, how they would communicate that to all staff, and what their plan would be for re-starting.

Thank you jfrey123 and everyone.

I have enough info to flesh the scenario out for us.

Lets hope that no one on IFSQN has to actually deal with said scenario IRL.

Hi Spicy,

To my mind there are quite a few H&S related preventive actions you can take to prevent or even help manage such an incident, such as:

Barrier protection of gas lines to prevent accidental damage

Automatic cut-off valve on pressure drop for your gas lines

Isolation valve actuator buttons near exit

Kind regards,

Tony