One for Mike

Mars recalling chocolate

http://www.bbc.co.uk/news/business-40226415

Cadbury had a similar problem some years ago, and had to withdraw a lot of chocolate. The withdrawal is necessary , though the risk of illness is probably (in both the Cadbury and Mars cases) extremely low other than to the very young (who should not be eating chocolate) or those with very much reduced immune systems. Assuming that there is one source of contamination (which I would think is almost certain) then it must be in the chocolate as Galaxy bars are one of the lines, and they contain only chocolate. Therefore the contamination must be in the milk portion or the sugar, as the cocoa portion is roasted and this would destroy any salmonella. It is difficult for salmonella to grow in chocolate, and so that is why, unless the original contamination is vast, I say that illness risk is low. I find it a little peculiar that they say less than 3000 units were affected (unless the BBC report has quoted Mars incorrectly), as that is a minute fraction of likely factory production, especially as TWO best before dates are quoted. The fact that these two dates are exactly one week apart raises the (to me only probably) interesting conclusion that they only change their BB dates every week . Yet this would mean that the affected items were produced over 2 weeks, so how can less than 3000 units be affected?.
Sorry for rambling on, but it all , as reported, sounds a bit peculiar

As usual a great and concise answer Thanks Mike.

It could be production just before and just after the moment when the BB date changes.

Yes but that does not explain the amazingly small number of units that are said to be affected. Say that all the units affected were Galaxy, which are all chocolate, and that it was the c100g size. This would correspond to only 300Kg chocolate, and if it was a covered unit, then a lot less. 300Kg would seem a lot to the public, but cannot see how any contamination could be limited to such a small amount