We recently had a micro hit (Salmonella sp.) as part of our positive release program and we are trying to find the vector but so far failing to do so.
We tested all raw material lots and carried out a full environmental swab program of the affected room (drains, walls, floor etc.) but all came back negative (375g samples for the raw materials). The hit came back part way through the cleaning process so swabbing was done post sanitation.
- Product is dry blended, contains some vegetable powders, starches, HVP and creamer powder plus salt/ other 'inert' ingredients
- Most raw materials are received on a COA basis only so are not sampled for micro testing at receiving stage (virtually all treated with some exceptions, all pathogen negative tested by manufacturer)
- Entire facility is dry blending
- We have not ever had a positive in the facility (past 3 years)
- Product was run in several batches over several days, positive came in part way through blending but no obvious candidate from that info (e.g. changing material lot)
- US based, BRC certified
Next steps- all possibly affected material is on hold, I will recommend to destroy or irradiate all of the product and raw material partials. Other than that, I am unsure where else to go.
Are there other things I can be doing here? What is the likelihood of an asymptomatic carrier? We have had no reports of anyone suffering from gastrointestinal issues over the last few months so nothing obvious there. What happens if we can't find a vector? How can I best mitigate any risks from using the same room or equipment for the next production?
Your valuable input would be gratefully received...
This sounds like a big headache for you. I had a similar situation at one of our factories last year, although luckily only one ingredient was implicated so we managed to find the source.
Hank’s comments are great & I agree, apart from looking at highest % ingredient in your mix, fruit & vegetables are a risk, especially those from developing countries where agricultural practices may not meet GAP requirements & there is potential for contamination through irrigation water & inadequately treated manure. Unless your powder producers use a validated heat step during powder production, small amounts of pathogens can be present. In those instances contamination will not be found throughout a batch but in “pockets”.
Your suppliers may have provided you with COAs but unless their loads are homogenous & they have a very robust sampling procedures (eg. milk powder factories where a “trickle sampler” is used to capture 2.5g amounts throughout a batch for screening in 750g) they don’t tell the full story. As you’ll know this is precisely why HACCP was developed to avoid reliance on end point micro testing.
Also you have another issue – if your suppliers have never found pathogens at their production site, either in ingredients or environmental swabs they are likely to question the validity of your results (which was the same issue I had last year) and point to their COAs as ‘proof’ that there were no pathogens present. I spent months trying to explain the logic of statistical sampling to my senior management team & to the supplier – without much success…. Painful!
This also sounds like a very costly experience so I would highly recommend that, as well as serotyping the positive found you also consider Whole Genome Sequencing – not cheap at about $500 per test but this was hugely useful for us because the WGS results provided a clear link to the ingredient, which had been sourced from Asia. The particular organism found had been linked to that growing region in Asia & thus we were, eventually, able to claim compensation from the supplier.
Best of luck!..