According to google ...Panjeeri Laddoos are fed to new mothers post delivery as they fall under hot food category and hence help in lactation. A couple of forums even go on to say that they haven't heard of people eating it during pregnancy as it generates too much heat to be good for the pregnant woman/foetus (http://gupshup.org/gs/parenting-household-affairs-and-cuisine-corner/211272-panjara-pregnancy.html).
While I am most certain, Ishwari did not mean to harm Sona by feeding her Panjiri laddoos (her intention was to serve high protein diet), her obsessive love for the unborn child sure made her over compensate, thus once again proving that ...to be at the receiving end of Ishwari's love is suffocating and therefore harmful...be it for Dev, Sona or the unborn/child.
I believe, Neha grabbing a laddu despite Ishwari stalling her, only to discover the salty nature of it symbolizes two things. One, Neha will do what it takes to not let Sona enjoy Ishwari's love as she believes it to be hers. Two, Neha will be the one to discover that Sona is not pregnant and she will be the one who will disclose Sona's non-pregnancy truth to everyone including Ishwari.
The truth of course is bitter...spit out salty, in this case. Therefore, following the non-pregnant revelation a shocked Ishwari will desperately try to make sense of the mess...just like she tries to figure out how the laddus ended up being salty. She may search for the positive in the bad situation, just like she tries to find the sweet batch of laddus amongst the salty ones.
While I have no idea as to what the CVs have planned going forward, going by the symbolism, Ishwari upon discovering the truth about Sona's pregnancy may try to be understanding as it was her son who caused the confusion (just like she cannot blame anyone else for the salty laddus as it was her mistake) and that is symbolized by the way she searches for the sweet laddus and tries to seperate them from the bad ones. Of course, this understanding of hers will stem from that space in her mind where she thinks Sona will make her a grandmother soon.
However, when Ishwari tries to seperate the good batch of laddus from the bad to fix the problem (trying to find the good in a bad situation) Neha's hand comes in between and the whole lot is toppled, and it becomes a jumbled mess. This clearly denotes that Neha once again will be the one to reveal that Sonakshi's inhospitable womb issues and Ishwari's caring understanding demeanour will be tested. Not only is it a big mess in terms of all broken laddus mixed and jumbled on the floor but the platter falls with a big bang. Therefore the scene where Sona's inhospitable womb truth is revealed, will not only be messy but also loud.
How will Ishwari react upon learning that the chances of her being a grandmother are 7% ...only time will tell. RR exclaiming it is apshagun' also symbolizes her role as the instigator of future problems wherein she will poison Ishwari against Sona.
Thus, the CVs have left us in a suspenseful state as to what Ishwari's stance will be following the entire truth revelation.
This post is purely based on what I perceived the laddoos scene to symbolize. In no way am I claiming that it'll be the future course of the story.
P.S - from the segment...things seemed to have unravelled pretty fast. We will need to wait and watch who revealed what to Ishwari and how she'll progress from thereon. And from the segment we also know that Ish comes to know about non-pregnancy and infertility issue together. There goes my step by step revelation to toss :D