A salmonella question: Does salmonella reproduce only in living animal

[hedgehog]

tissue, any animal tissue (meat), or both those and plant tissue? In other words, can a trace of salmonella multiply to contaminate peanut butter, or does the mixing of th peanut butter spread an initial number of salmonella spores though the batch or what?

Bonus question about testing: say I test s spoonful from this part of the batch and it comes back positive. Suppose I then test a spoonful from that corner and it comes back negative. Now what?

[hlthe2b]

1. Salmonella is a bacterium and as such reproduces

as long as there are the vital nutrients required... That's how one grows it in media on a petri plate. Growth is not dependent on its presence in tissue or cells (i.e., it is not an obligate parasite). Like most bacteria as long as it has favorable temperature, ph and nutrients it can survive and multiply.... Salmonella can survive for weeks in manure, for example.

One could certainly have batches of both contaminated and uncontaminated peanuts so that certain batches would be more of less contaminated (more or less infectious dose). However, in a small volume container it is hard to imagine that the extremes would be as you describe--i.e., one teaspoon from the top contaminated, that from the far corner, not... But, it is certainly possible to have fewer organisms and thus have a false negative depending on the test used. Culture of food and biologic specimens for bacteria is the gold standard--one knows the organism is there and you get the isolate that can be further manipulated and compared against other strains of the same organism from other outbreaks. But it is not uncommon to have evidence of contamination and not be able to culture the bacteria (low dose, poor temperature or other holding conditions, etc.). However PCR which looks for very minute evidence of the organism's genetic material (e.g., antigen) is so very sensitive, that this (false negatives) w0uld be far less likely.

I hope this helps.

[hedgehog]

2. Thanks - I knew that someone here would have the info.

30 some year ago I worked for a now absorbed company famous both for its pet foods and its breakfast cereals. The plant I worked at made breakfast cereal.I can remember that our plant bacteriologist was puzzled when the order came down from corporate to sample various surfaces for salmonella. At the time, it was believed that grain products did not carry salmonella, that it was strictly a problem with raw meat.