Tenacity of Bacillus cereus and Staphylococcus aureus in dried spices and herbs

Intrinsic and extrinsic factors influencing Bacillus cereus spore inactivation in spices and herbs: Thermal and non-thermal sterilization approaches

The presence of Bacillus cereus in spices and herbs has posed a detrimental effect on food safety. The absence of thorough testing, comprehensive reporting, and vigilant surveillance of the illness has resulted in a significant underestimation of the true prevalence of foodborne illness caused by B. cereus. B. cereus spores are resistant to thermal processing (superheated steam, microwave, radiofrequency, infrared) that remains a significant challenge for the spice industry. Non-thermal techniques, such as cold plasma, gamma irradiation, and electron beam irradiation, have gained significant interest for their ability to inactivate B. cereus spores. However, these technologies are constrained by inherent limitations. The composition of B. cereus spores, including dipicolinic acid, divalent cations, and low water content in the core, contributes significantly to their resistance properties. This review delves into the different factors that impact B. cereus spores in spices and herbs during sterilization, considering both intrinsic and extrinsic factors. This review also discussed the various techniques for inactivating B. cereus spores from spices and highlighted their effectiveness and constraints. It also provides valuable insights for enhancing sterilization strategies in the spices and herbs industry.

Prevalence, Toxin Genes, and Antibiotic Resistance Profiles of Bacillus cereus Isolates from Spices in Antalya and Isparta Provinces in Türkiye

Bacillus cereus is a pathogenic bacterium commonly found in nature and can produce toxins that cause food poisoning. This study aimed to detect the prevalence of B. cereus group bacteria in 50 unpackaged and 20 packaged spice samples frequently used as flavoring in Turkish cuisine, as well as investigate the presence of toxin genes and antibiotic resistance in the isolates. A total of 48 B. cereus group bacteria were isolated from 27 of 70 (38.57%) spice samples. The prevalence of B. cereus group bacteria in packaged (25%, 5/20) and unpackaged (44%, 22/50) spice samples did not differ significantly (P ˃ 0.05). All B. cereus group isolates were identified as B. cereus sensu stricto (B. cereus) using molecular methods. The hemolytic activity tests revealed that the most strains (44/48, 91.67%) are β-hemolytic. The distributions of toxin genes in isolates were investigated by PCR. It was determined that all isolates were identified to have 2-8 toxin genes, except B. cereus SBC3. The three most common toxin genes were found to be nheA (47/48, 97.92%), nheB (46/48, 95.83%), and entFM (46/48, 95.83%). All B. cereus isolates were susceptible to linezolid and vancomycin, while 35.42% (17/48) showed resistance to erythromycin. Multi-drug resistance (MDR) was detected in 8.3% (4/48) of B. cereus isolates, while 33.33% of the isolates showed multiple antibiotic resistance (MAR) index values higher than 0.2. The findings indicate that B. cereus may pose a health risk in packaged and unpackaged spices if present in high quantities. Therefore, the presence of B. cereus strains in both packaged and unpackaged spices should be monitored regarding consumer health and product safety.

Combined Effect of High-Pressure Processing with Spice Extracts on Quality of Low-Salt Sausage during Refrigerated Storage

The study evaluated the combined effect of high-pressure processing (HPP) and spice extracts on low-salt sausages during refrigerated storage. Physicochemical and microbiological characteristics of the sausages were determined. HPP treatment increased the thiobarbituric acid reactive substances (TBARS) value and the carbonyl content of the samples (p < 0.05), which meant lipid and protein oxidation was accelerated. Adding clove and cinnamon extracts can retard the oxidation caused by HPP (p < 0.05). The pH of the sausages treated with both the spice extracts and HPP maintained a higher pH value during the storage (p > 0.05). Compared with the samples treated with HPP or with the spice extracts alone, the combined treatment observably inhibited the growth of spoilage bacteria (p < 0.05) and improved the microbial community. The results demonstrated that the use of clove and cinnamon extracts in conjunction with HPP improved the storage quality and prolonged the shelf-life of the low-salt sausages. Thus, the combined use of spice extracts and HPP can be developed as a promising way to preserve low-salt meat products.

Antibiotic resistance pattern of the allochthonous bacteria isolated from commercially available spices

Spices are often used in dried form, sometimes with significant microbial contamination including pathogenic and food spoilage bacteria. The antibiotic resistance represents an additional risk for food industry, and it is worthy of special attention as spices are important food additives. During our work, we examined the microbiological quality of 50 different spices with cultivation methods on diverse selective media. The identification of the most representative bacteria was carried out using 16S rDNA gene sequence analysis. Antibiotic resistance profiling of twelve identified Bacillus species (B. subtilis subsp. stercoris BCFK, B. licheniformis BCLS, B. siamensis SZBC, B. zhangzhouensis BCTA, B. altitudinis SALKÖ, B. velezensis CVBC, B. cereus SALÖB isolate, B. tequilensis KOPS, B. filamentosus BMBC, B. subtilis subsp. subtilis PRBC2, B. safensis BMPS, and B. mojavensis BCFK2 isolate) was performed using the standard disk-diffusion method against 32 antibiotics. The study showed that the majority resistance was obtained against penicillin G (100%), oxacillin (91.67%), amoxyclav (91.67%), rifampicin (75%), and azithromycin (75%). Our findings suggest that spices harbor multidrug-resistant bacteria.

How can packaging, source and food safety management system affect the microbiological quality of spices and dried herbs? The case of a developing country

Spices and herbs are widely used in almost all types of food preparation and their microbial contamination may cause spoilage and pose public health risk. Thus, the aim of this study was to assess the effect of packaging, source and a food safety management system (FSMS) on the microbiological quality of spices and dried herbs in a developing country, like Lebanon. For this, a total of 96 composite samples of thirteen most commonly consumed types of spices and dried herbs were collected twice at three-month interval. Each type was purchased in 5 common brands from 4 categories: packaged in companies with FSMS, packaged in companies without FSMS, packaged imported, and unpackaged. Total aerobic mesophilic bacteria (TAMB), sulfite reducing anaerobic bacteria, C. perfringens, coliforms, E. coli, yeasts and molds were found in 89%, 43%, 18%, 15%, 1% and 54% of the samples, respectively. All samples were negative for Salmonella. One per cent, 4%, 6%, 1% and 7% of the samples had unacceptable levels of TAMB, coliforms, sulfite reducing anaerobic bacteria, E. coli, yeasts and molds, respectively. Among the four categories, imported samples had the lowest microbiological load, followed by locally packaged in companies with FSMS, then locally packaged in companies without FSMS and the highest microbiological load was for the unpackaged spices and dried herbs. This study highlighted the importance of storage conditions, good hygienic practices, process controls and FSMSs in the spices and dried herbs sector.

The Bacillus cereus Food Infection as Multifactorial Process

The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.

Dehydrated foods: Are they microbiologically safe?

Dried foods are low water activity foods with water activity ranging from 0.03 to 0.7. They are commonly misconstrued to be inherently safe from food borne pathogenic bacteria. However, there are many reported cases where many food borne illnesses were caused by the consumption of dried foods contaminated with Salmonella spp., Cronobacter spp., Staphylococcus spp. and E. coli. In this work, we have systematically reviewed the literature dealing with the effect of drying/dehydration on the survival of pathogenic microorganisms with special focus on Salmonella spp. We have also reviewed and synthesized the literature dealing with the effect of drying process on microorganisms in dried vegetables, meat, fish, spices, mushroom and powdered foods. This review concludes that dried foods are not inherently safe microbiologically and required other hurdles to achieve microbial safety.