The story of Khiki cheese begins with Iran’s vast flocks of sheep and goats, animals far better suited to the country’s arid and mountainous landscapes than cattle. According to figures cited in the review from the Iranian Ministry of Agriculture, the country held roughly 49.4 million sheep and 16.8 million goats in 2023, and nomadic communities breed the majority of them. These herders produce more than 460,000 tons of milk annually, and cheese made from that milk provides an essential source of income and trade. Khiki cheese varieties alone exceed 2,500 tons per year, produced across at least ten provinces including Gilan, North Khorasan, Semnan, West Azarbayjan, Kurdistan, Lorestan, Khuzestan, Fars, and Kerman.

What makes Khiki cheese genuinely distinctive is its ripening vessel. The practice of maturing cheese inside animal skin bags is shared by only a handful of traditions worldwide, including Tulum cheese in Turkey, Darfiyeh in Lebanon, Motal in Azerbaijan, Mišina in Croatia, Mjeh in Bosnia and Herzegovina and Montenegro, and Bouhezza in eastern Algeria. Preparing the bag is an art in itself: the skin is carefully peeled without tearing, scraped clean of flesh, washed, soaked in salt for 24 hours, and sun-dried for 20 to 25 days. All openings except the neck are sewn shut, and the interior is coated with salt and diluted yogurt before the cheese is introduced. Producers generally prefer goatskin because it is stronger than sheepskin.

The production process relies entirely on raw, unpasteurized milk from sheep, goats, or a mixture of the two, with no industrial starter cultures. Fresh milk is filtered, rennet is added, and after about an hour the coagulated curd is drained in cotton cloth, salted to accelerate dehydration, and submerged in 10 to 12 percent brine for 20 to 45 days. The hardened curd is then cut into small cubes and packed into the salted skin bag, which is sealed and stored at roughly 6 to 12 degrees Celsius for three to nine months. Regional variations abound: Kordi cheese from North Khorasan is periodically topped up with whey, dough, or milk to prevent moisture loss, while Aftar cheese from Semnan is ripened in a cave and brined in a saturated 22 percent salt solution. In Lorestan, the bag itself is coated with kashk, a dehydrated yogurt product, before filling.

Because every batch starts with raw milk and a hand-prepared skin, the chemistry of the final cheese varies enormously. Reported pH values span from 4.46 to 6.74, titratable acidity from 0.86 to 13.52 percent lactic acid, moisture from 12.14 to 40.92 percent, fat from 3.8 to 28 percent, and protein from 4.57 to 27.79 percent. The review’s authors caution that this variability is so broad that Khiki cheese cannot be uniformly classified as a full-fat semi-hard cheese under the Codex Alimentarius standard, since the fat-in-dry-matter and moisture-on-a-fat-free-basis values required for that designation have not been consistently measured across varieties.

Ripening inside the permeable skin bag drives a cascade of biochemical transformations. Proteolytic enzymes from rennet, the raw milk, and the bag’s own microflora progressively break down casein into peptides and free amino acids, a process tracked by the water-soluble nitrogen index, which can reach over 61 percent of total nitrogen. Lipolysis releases free fatty acids, particularly short-chain ones that give the cheese its sharp, buttery aroma, and these fatty acids serve as precursors for methyl ketones and esters that deepen the flavor. Meanwhile, salt diffusing inward from the brine tightens the protein matrix through enhanced hydrophobic interactions, and scanning electron microscopy studies show the casein network becoming denser and more compact during the first month, with pore size and roughness increasing as ripening advances.

The microbial ecology of Khiki cheese is where the story becomes truly compelling. Lactic acid bacteria dominate, with counts between 10^3 and 10^6 colony-forming units per gram, and the dominant genera are Lactobacillus, followed by Enterococcus and Pediococcus. Species such as Lactobacillus plantarum, L. casei, L. paracasei, L. brevis, and L. acidophilus have all been isolated, alongside Enterococcus faecium and E. durans. These organisms do more than sour the cheese: they produce organic acids, hydrogen peroxide, and bacteriocins that suppress pathogens. Studies show that coliforms and Staphylococcus aureus detected early in ripening are typically eliminated by the second month, and Salmonella has never been detected in ripened Khiki cheese across multiple investigations.

Food safety remains the central challenge. Because the cheese is made from raw milk under variable hygienic conditions, pathogenic contamination is a real risk, and some E. coli strains isolated from Khiki cheese have carried multiple virulence genes. Pasteurization would eliminate these hazards, but it also destroys the wild lactic acid bacteria responsible for the cheese’s prized flavor and texture; sensory studies consistently show that raw-milk Khiki cheese outperforms its pasteurized counterpart. The solution proposed by researchers is to develop starter and adjunct cultures from the cheese’s own native strains, allowing safe industrial production from pasteurized milk without sacrificing authenticity.

Remarkably, the bacteria of Khiki cheese are proving useful far beyond the dairy case. Strains isolated from the cheese have been deployed as starter cultures for fermented sausages, as anti-yeast agents in the traditional yogurt drink doogh, and as postbiotic coatings that extend the refrigerated shelf life of beef. Even more striking are the probiotic findings: Lactobacillus plantarum strains from Khiki cheese survived simulated gastric conditions, reduced blood glucose and oxidative stress in diabetic rats, and inhibited Listeria monocytogenes and Salmonella. A Lacticaseibacillus casei strain from the cheese showed antimicrobial activity against multiple foodborne pathogens and even cytotoxic effects against cancer cell lines in vitro, while Lactobacillus brevis M3R3 displayed antioxidant and cholesterol-removal properties with a clean safety profile. The authors argue that documenting and standardizing these ancient techniques, classifying varieties by milk type, ripening duration, and compositional indices, could carry a nomadic heritage food into industrial production while preserving the microbial treasures hidden inside its humble skin bags.

Subject of Research: Traditional production, microbiota, and physicochemical properties of Iranian Khiki cheese ripened in animal skin bags

Article Title: Production process, microbiota, and physicochemical composition of traditional cheese products: A case study of Khiki cheese

Article References: Fallah, A. A., Sarmast, E., Jafari, T., Ghasemi, M., & Mousavi Khaneghah, A. (2026). Production process, microbiota, and physicochemical composition of traditional cheese products: A case study of Khiki cheese. Journal of Agriculture and Food Research, 31, Article 103245. https://doi.org/10.1016/j.jafr.2026.103245

Image Credits: AI Generated

DOI: 10.1016/j.jafr.2026.103245

Keywords: Khiki cheese, traditional cheese, Iran, goatskin bag, lactic acid bacteria, raw milk, probiotics, cheese ripening, food safety, Lactobacillus plantarum, dairy microbiology, fermented foods

The scale of the question matters. Obesity now affects more than one billion people worldwide and is rooted in a web of chronic low-grade inflammation, metabolic dysfunction, and disruption of the gut microbiota, the trillions of microbes that inhabit the human intestine. Current pharmacological options such as GLP-1 receptor agonists have transformed the treatment landscape, yet they remain expensive, demand long-term adherence, and can carry side effects that lead many patients to discontinue treatment. Against that backdrop, researchers have intensively explored whether live bacteria could tilt the metabolic balance in a favorable direction. Lactobacillus plantarum has attracted particular attention because animal and mechanistic studies indicate it can alter intestinal microbial communities, improve serum metabolic profiles, modulate immune signaling, and even influence liver enzymes associated with fatty liver disease. Human trials, however, have produced a confusing mixture of positive, neutral, and negative results, leaving clinicians without a clear verdict.

To resolve that uncertainty, the research team followed PRISMA reporting guidelines and prospectively registered their protocol on PROSPERO under the identifier CRD420251102722. They systematically searched PubMed, the Cochrane Library, and Google Scholar through May 2025, ultimately identifying eighteen randomized controlled trials encompassing 1,310 participants. To be eligible, studies had to enroll non-diabetic adults with a body mass index of at least 25 kilograms per square meter and compare Lactobacillus plantarum supplementation against a control group. The primary outcomes were body weight and BMI; secondary outcomes included lipid profiles, glycemic indices, inflammatory biomarkers, liver enzymes, and body composition measures such as fat mass and waist circumference. Each trial was appraised for risk of bias using the revised Cochrane RoB 2.0 tool, and the certainty of evidence for every outcome was graded with GRADE, which penalizes findings for inconsistency, imprecision, indirectness, and publication bias.

The headline result was a statistically significant reduction in body weight. Across the pooled trials, supplementation with Lactobacillus plantarum produced a mean difference of minus 1.23 kilograms compared with controls, with a 95 percent confidence interval stretching from minus 1.97 to minus 0.49 kilograms and a p value of 0.001. Heterogeneity was moderate, with an I-squared statistic of 49 percent, meaning roughly half of the variation between studies could be explained by chance rather than real differences in effects. BMI fell by a mean of 0.28 units per square meter, and waist circumference shrank by an average of 1.36 centimeters, a finding with a p value of 0.003 that is notable because abdominal fat is the depot most strongly linked to cardiometabolic risk. The analysis also documented improvements in liver enzymes, suggesting a possible hepatoprotective signal that aligns with mechanistic work showing the bacterium can dampen oxidative stress in liver tissue.

Perhaps the most consequential judgment the authors made was about how much to trust these numbers. They assigned high certainty to the body weight finding, the strongest rating available, and moderate certainty to the reductions in BMI, waist circumference, fat mass, and liver enzymes. In contrast, the evidence for improvements in lipids, glycemic measures, and inflammatory biomarkers was rated only low certainty. This layered assessment is important because inflammatory and lipid outcomes have often driven enthusiastic claims about probiotics. Here, the GRADE analysis effectively tempers that enthusiasm: while the anthropometric effects rest on solid footing, the immunometabolic benefits remain provisional and require better-designed trials before they can be considered established.

The subgroup analysis offered a tantalizing hint about formulation. Reductions in weight and BMI appeared more pronounced in trials that used multi-strain formulations containing Lactobacillus plantarum alongside other species than in trials testing single-strain supplements. However, the formal tests for subgroup interaction were non-significant, and the authors were careful to note that this means the evidence is insufficient to confirm a true difference in effect by formulation type. The observation is biologically plausible, since microbial communities often function through redundancy and cross-feeding networks in which complementary strains reinforce one another’s metabolic activities. Still, the statistical caution here is a model of restrained interpretation in a field frequently criticized for overstating strain-specific claims.

How could a stomach-dwelling bacterium nudge body weight downward at all? Several mechanisms have support from the broader literature cited in the analysis. Probiotics can modulate the composition and function of the gut microbiota, which in turn affects energy harvest from the diet, production of short-chain fatty acids, and the integrity of the intestinal barrier. A weakened barrier allows bacterial products such as lipopolysaccharide to enter circulation, fueling the systemic low-grade inflammation, sometimes called metaflammation, that underpins insulin resistance and adipose tissue dysfunction. Lactobacillus plantarum strains have also been shown to influence appetite-regulating hormones and adipocytokines, reduce anti-adipogenic signaling pathways, and alter bile acid metabolism, all of which could plausibly contribute to modest weight reduction. Trials included in the review tested a wide range of delivery formats, from fermented milk and yogurt to capsules and powders, and several specific strains such as OLL2712, Dad-13, K50, LMT1-48, and SKO-001 appeared in individual studies.

The authors of the new analysis interpret the effect size candidly. A reduction of roughly 1.2 kilograms will not rival the double-digit weight losses achievable with newer medications, but the literature on intentional weight loss shows that even modest reductions of 2 to 5 percent of body weight can improve cardiovascular risk factors, and probiotic supplementation carries a favorable safety profile in the trials reviewed. In that sense, the findings position Lactobacillus plantarum not as a replacement for established therapies but as a potential adjunct, one that might be layered onto lifestyle interventions at low cost and low risk. The improvements in liver enzymes add further interest given the rising prevalence of non-alcoholic fatty liver disease, which shares the same metabolic soil as obesity and currently has limited approved pharmacological treatments.

Limitations remain. The eighteen trials varied in strain, dose, duration, and delivery vehicle, and the moderate to high heterogeneity in the BMI analysis signals genuine diversity in how participants and interventions behaved across studies. Most trials were relatively short, and no pooled estimate speaks to whether weight loss persists after supplementation stops. The exclusion of participants with diabetes narrows the applicability of the findings to that large patient group. The authors call for standardized, long-term randomized trials that specify strains, doses, and populations in ways that allow direct comparison. Until those trials arrive, the meta-analysis provides the clearest synthesis yet of what this popular probiotic actually does: it delivers a small, statistically reliable, and high-certainty reduction in body weight in adults with overweight or obesity, with moderate-certainty support for slimmer waistlines, less fat mass, and healthier liver enzyme levels, while claims about lipids, blood sugar, and inflammation await stronger evidence.

Subject of Research: The effects of Lactobacillus plantarum probiotic supplementation on anthropometric and inflammatory parameters in adults with obesity, evaluated through a GRADE-assessed systematic review and meta-analysis of randomized controlled trials.

Article Title: Influence of Lactobacillus plantarum on anthropometric and inflammatory parameters in obesity: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials

Article References: Khattak, M. H., Abbas, S. A., Zaryab, U., Bibi, H., Siddiqui, S. A., Khan, B. W., Zeeshan, N., Khan, M. F., Amjad, M. M., Khan, N. A., Mehmood, Y., & Khan, H. W. (2026). Influence of Lactobacillus plantarum on anthropometric and inflammatory parameters in obesity: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials. International Journal of Obesity. https://doi.org/10.1038/s41366-026-02221-0

Image Credits: AI Generated

DOI: 10.1038/s41366-026-02221-0

Keywords: Lactobacillus plantarum, probiotics, obesity, meta-analysis, body weight, body mass index, waist circumference, gut microbiota, inflammation, liver enzymes, randomized controlled trials, GRADE