A Study Finds Sidr Honey From Morocco Halts Salmonella at Tiny Doses

• Pollen analysis confirmed all twelve honey samples were genuine monofloral Sidr honey, with Ziziphus lotus pollen making up between 40 and 91 percent of the grains counted in each sample.
• Every sample met Codex Alimentarius standards for moisture, acidity, and freshness, and low levels of hydroxymethylfurfural indicated the honey had not been overheated or poorly stored.
• Total phenolic content ranged from 48.3 to 91.8 milligrams of gallic acid equivalent per 100 grams, and antioxidant strength tracked closely with that range.
• In laboratory dishes, honey samples stopped Salmonella typhimurium from growing at concentrations as low as 0.003 milligrams per milliliter, and in every sample the honey killed the bacteria outright rather than only holding back its growth.
• Most samples contained lead levels above the European Union's limit for honey, which the researchers attributed to regional soil and farming conditions rather than the honey's botanical source.

In a laboratory in Morocco, a few thousandths of a milligram of Sidr honey, drawn mainly from the flowers of the wild jujube tree Ziziphus lotus, was enough to stop Salmonella from growing in a dish.

A study of twelve honey samples collected across Morocco's Middle Atlas mountains between 2019 and 2021 found that this monofloral Sidr honey inhibited two foodborne pathogens in laboratory dishes and carried a wide, variable set of antioxidant compounds. Against Salmonella typhimurium, the honey prevented visible bacterial growth at concentrations as low as 0.003 milligrams per milliliter, and in every sample tested, only slightly higher concentrations killed the bacteria outright rather than merely holding it back.

Researchers confirmed each sample's floral origin through pollen counts, finding Ziziphus lotus pollen made up between 40 and 91 percent of the grains in every honey, before running physicochemical, mineral, sugar, and polyphenol tests. Antibacterial activity was measured with a standard broth dilution method against Salmonella typhimurium and Listeria monocytogenes, comparing the lowest concentration that stopped visible growth with the lowest concentration that killed the bacteria outright. Antioxidant capacity was assessed separately using two free radical tests, and twenty seven distinct phenolic compounds were identified and measured using mass spectrometry.

Against Listeria monocytogenes, results were more mixed, with four of the eleven samples tested killing the bacteria outright and the rest merely slowing its growth, a reminder that the same honey can act differently depending on which microbe it meets. The variability ran through the honey's chemistry too. Even though pollen counts confirmed all twelve samples as genuine Sidr honey, total phenolic content ranged from 48.3 to 91.8 milligrams of gallic acid equivalent per 100 grams, and catechin, detected in only four of the samples, ranged from about 1 milligram per kilogram in one honey to more than 1,600 milligrams per kilogram in another. Ziziphus lotus has long featured in Moroccan folk medicine for digestive and blood sugar complaints, and this kind of chemical range helps explain why a plant with a single name can support such varied traditional uses.

These are bench tests on bacteria in petri dishes, not on people, so they say nothing about how the honey would perform against an infection in the body. The study's own samples also showed lead levels above the European Union's limit for honey in all but one case, which the researchers linked to regional soil and farming conditions rather than to the jujube tree itself, a reminder that a honey's safety depends on where and how it was produced.

It is exactly this kind of variation, real even among honey that shares a name, a flower, and a mountain range, that leads Tayab to treat every batch of the Sidr honey it sources as its own case to verify rather than something a label alone can promise.