I think you have slightly misunderstood the microbiology.
Listeria is a genus (a group of bacteria). L.monocytogenes is the major human pathogen in the group. Some of the other members do have some pathogenic characteristics but mainly for other creatures. Can see this link if seriously interested –
Or this link for a less heavyweight view -
The Bad Bug Book (2012) comments -
Of the five other species in the genus Listeria – L. grayi, L. innocua. L. ivanovii, L. seeligeri and L. welshimeri – only L. ivanovii is considered pathogenic, and mainly in ruminants, rather than in humans.
The traditional test procedure on a sample of the product is in principle something like –
(1) apply a screening procedure for detection of any members (species) of the genus (group) Listeria.
(2) examine any positive results from the screen to see if the detected species is L.monocytogenes
(probes are faster)
So, in principle, it is possible to have a positive result for Listeria and a negative result for L.monocytogenes.
I am not routinely working with Listeria/L.monocytogenes but in such a case I would imagine that a random, final, external laboratory negative result for L.mono. would usually be reported as “OK”. Such a conclusion typically cancels reporting of any presumptive screening data unless some very unusual event occurs, eg noticing some other significant risk.
However, here is one Canadian interpretation for Listeria / L.monocytogenes for, I think, local food processors.
listeria monocytogenes policy, 2011.pdf 1.16MB
From a quick look, the answer to yr type of question depends on the specific product category. And (see the Flow charts provided) may well be “problematic”, ie require further expert advice.
The answer for imported goods will probably require similar information regarding Canadian import standards.
Are you seeking a legally accurate opinion on some actual data/situation or is this a purely hypothetical query in the sense of a safe / wholesome commercialisation of your product?
Rgds / Charles.C