A shipboard memory, an obscure Indian food rule, and the strange history behind the world’s most controversial seasoning.

We were carrying motor spirit and aviation turbine fuel — two of the most volatile cargoes a product tanker handles — and the thing we were actually nervous about before arrival was a jar of Ajinomoto in the galley.

That’s not an exaggeration of memory. Every pre-arrival routine on the ship covered the cargo: tank atmospheres checked, static electricity precautions briefed, the mate walking the deck confirming valves and sounding tapes before we approached Marmugao to discharge. And somewhere in that same routine, the Chief Steward was quietly clearing the dry store of anything that looked like decanted MSG. Not because it was dangerous. Because a Port Health Officer finding it wasn’t going to be treated as an oversight — it was going to be treated as contraband. Something hidden, not something merely undeclared.

Why a condiment worried us more than the fuel

Rule 64B of India’s Prevention of Food Adulteration Rules, 1955, did more than require a warning label. It permitted MSG in food subject to a label declaration under Rule 42(5), capped total glutamate content in ready-to-serve food at 1%, and prohibited adding it to food meant for infants under 12 months. Nobody on a merchant ship in the early 1990s was provisioning with that rule in mind. Galley stores got decanted the way they always had — bulk MSG, seasonings, and white powders transferred into glass jars, plastic tubs, or whatever container was on hand, none of it carrying local statutory markings because none of it was ever meant to be inspected against Indian food law.

Marmugao’s PHOs were where that gap turned expensive. Boarding under PFA authority, they went through the galley and dry store with a thoroughness Chief Stewards talked about for the rest of the voyage. An open, unlabelled jar of Ajinomoto satisfied none of Rule 64B’s conditions — and among the crews who called there, the understanding was blunt: an inspector who found one could call it substandard or adulterated on the spot. That finding didn’t stay contained to the jar. It invited closer scrutiny of the entire dry store, and it carried the risk every Master actually feared: a hold on port clearance, over a seasoning, while a full tanker sat waiting to discharge.

So the fix was practical, not principled. Before we dropped anchor off Marmugao, the MSG got locked away, landed, or thrown out — smuggled off the ship’s own inventory before anyone official could find it. Nobody on board was debating glutamate chemistry. We were making sure a jar of Ajinomoto didn’t become the reason a motor spirit discharge got delayed.

Where the fear behind that rule actually came from

The caution PFA inspectors were enforcing traces back to one letter. On 4 April 1968, the New England Journal of Medicine published a note from a “Dr. Robert Ho Man Kwok,” describing numbness, weakness, and heart palpitations after eating at Chinese restaurants. Kwok floated three possible causes — salt, cooking wine, or MSG — and left the question open. The journal published it under the title “Chinese-Restaurant Syndrome,” and a run of follow-up letters from other physicians landed over the following months, each offering competing symptoms and competing explanations — a correspondence war, not a controlled trial. Subsequent letters increasingly zeroed in on MSG specifically, even though Kwok’s own letter had left the question open.

Mainstream press coverage followed that same drift, and the early animal research made it worse rather than better: the most cited studies involved injecting rodents — not feeding them — with massive, unnatural doses of pure MSG powder, a route and dosage with no relationship to a bowl of soup, but a striking enough result to keep the story alive.

A myth about the myth

Here’s the part that makes the story stranger than the seasoning it’s about. In January 2018, months before his death that September, retired orthopedic surgeon Dr. Howard Steel told Colgate University professor Jennifer LeMesurier — who’d just published an academic paper on the letter — that he’d fabricated the whole thing decades earlier as a $10 bet with a colleague. “Robert Ho Man Kwok” was supposedly his own invention, a play on words (“human crock”) he assumed readers would catch, and the “National Biomedical Research Foundation” the letter cited was, he said, made up entirely.

Except a real Dr. Robert Ho Man Kwok existed: a Maryland pediatrician and researcher who died in 2014. And by multiple independent accounts, a real National Biomedical Research Foundation of Silver Spring, MD, existed too — the exact institution Steel claimed he’d invented out of thin air. That discovery was serious enough that Colgate’s own magazine later appended a formal editor’s note to its original profile of Steel, stating that information had since come to light “calling into question Howard Steel’s role in the MSG controversy.” Nobody has produced a tidy final answer — NEJM says it’s never verified the letter’s authorship either way — but the man who spent his last year telling the story may not have been telling it straight. The myth has its own myth sitting underneath it.

Reading the hazard data instead of the headline version

PubChem’s aggregated GHS notifications for MSG are worth reading past the three-line version that circulates online. Of 409 supplier notifications on record, 406 report that the substance does not meet GHS hazard criteria at all. The minority that do assign codes — the H315 (skin irritation), H319 (serious eye irritation), and H335 (respiratory irritation) that show up on reagent-grade safety data sheets — describe the fine, dry, pure powder under bulk industrial or laboratory handling, not a food ingredient on a plate. Some reagent-grade SDS documents go further still, adding H372 and H400, again scoped to concentrated industrial material rather than dietary exposure. Worth stating plainly: GHS data describe occupational and chemical-handling hazards, not a food-safety risk assessment — the two shouldn’t be read as interchangeable.

An often-cited oral rat LD50 for MSG is around 16,600 mg/kg, indicating relatively low acute toxicity in that specific animal test — though LD50 is a measure of acute poisoning thresholds, not everyday dietary safety, so the figure illustrates rather than proves anything about a plate of food. One popular data point doesn’t survive checking at all: MSG’s NFPA 704 fire-hazard rating is often quoted online as 0-0-0, but NOAA’s own CAMEO Chemicals database — the authoritative source for that rating — lists it as simply unavailable. A plant handling MSG in bulk faces the same nuisance-dust exposure as one handling flour or fine table salt: eye and respiratory irritation from airborne particulate, managed with routine industrial hygiene, not a toxicological food hazard.

The rule outlived the ship routine it created

Rule 64B didn’t disappear with the PFA Act. The Food Safety and Standards Act, 2006, created FSSAI, but the older law wasn’t actually repealed until 5 August 2011, when FSSAI’s own regulations took over. The infant warning survived that handover — first into FSSAI’s 2011 Packaging and Labelling Regulations, and today into the Food Safety and Standards (Labelling and Display) Regulations, 2020. If anything, the wording has grown more cautious, not less: the current declaration reads “not recommended for infants below 12 months and pregnant women,” extending a warning Rule 64B once aimed at infants alone. An officer provisioning today would find a stricter version of the same warning on the same jar. What’s changed is that nobody has to smuggle it past Marmugao anymore — the label on the tin now does what the plastic tub never could.