A cigar is defined as a roll of tobacco wrapped in leaf tobacco or in a substance that contains tobacco (other than any roll of tobacco which meets the definition of cigarette) (1). Despite the abundance of literature on the composition of traditional conventional cigarettes, published research is limited on the physical and chemical properties of cigars. Interest in expanding fundamental knowledge and standardization has increased in the last few years. Hence, there has been a marked uptick in activity from industry, academic and private laboratories with regard to research and testing designed to better understand cigar properties. For example, there were 27 presentations or publications tracked by CORESTA on the topic in 2017, approximately the same number as the previous ten years combined (2).
The overarching aim of this work has been to advance the scientific knowledge of cigar tobacco content and the resulting deliveries of select smoke constituents while developing a foundational understanding of the inherent variability of the product.
Cigars are combustible tobacco products consisting of filler, binder, and wrapper derived from tobacco. Generally, cigars of all designs fall into two main categories: Handmade/Premium cigars and machine-made cigars (MMCs). Premium cigars are typically made from whole tobacco leaves of a single tobacco type (dark air cured); are hand rolled; are usually large, with burn times of up to several hours; and are relatively expensive compared with other tobacco products. For most premium cigars, unblemished leaves are required for the wrapper. The binder is also natural leaf and the filler is hand-rolled (i.e., not cut) (3). Alternatively, MMCs are typically made using homogenized natural leaf wrapper, with or without binder, and with cut tobacco for filler. MMCs are mass produced by machines and may contain Generally Recognized as Safe (GRAS) additives and/or non-tobacco components such as a mouthpiece. In this paper we attempt to summarize and comment on recent scientific efforts and analytical testing standardization efforts by the industry, and to discuss challenges and opportunities with regard to analytical efforts for the product category.
Approximately 1100 peer reviewed publications including extant monographs were systematically compiled from this subject-specific research. Digital data bases used to identify and screen the articles were the CORESTA website, University of California San Francisco library of tobacco industry bibliographies, FDA website and google scholar. On-line resources like Comsol (
In situations where different articles from the same authors were cited, the articles were scrutinized to ensure that the data from each study was independent of each other and without conflicts of interest.
Figure 1 shows a pictorial illustration of our method; depicting the huge statistical differences that exist between availability of published cigar literature, cigarette literature and that of e-cigarettes. Our observations in Figure 1 highlight an extremely limited availability of cigar science research publications, therefore literature as far back a 1950 up to 2021 was utilized to capture inter-generational scientific developments and milestones in the tobacco industry. Key words/phrases searched were cigar science, cigar tobacco, cigar regulation, cigar method development, cigar chemical analysis, cigar tobacco variability, cigarette tobacco, machine-made cigars, premium cigars, handmade cigars, cigar smoke constituents and cigar tobacco farming. All the articles were collated using the EndNote referencing tool (
All testing, whether content or yield related, are impacted by the tobacco and ultimately the growing conditions of that tobacco. There have been recent efforts to increase understanding in this area for cigar tobaccos. Some have argued that testing and reporting multiple constituents in cigar leaf and smoke without having in-depth knowledge of what drives the variability/variations will engender the submission of somewhat valueless and inconsequential data to the regulatory institutions (4). Generally, controls to minimize year-to-year variability from seed planting and harvesting to the finished tobacco leaf remain a challenge. Variability in cigar tobacco is a well-known issue and FDA has acknowledged that blend changes due to “natural variability” do not require a product to undergo premarket review Deeming Tobacco Products to be Subject to the Federal Food, Drug, and Cosmetic Act, as Amended by the Family Smoking Prevention and Tobacco Control Act; Restrictions on the Sale and Distribution of Tobacco Products and Required Warning Statements for Tobacco Products, 81 Fed. Reg. 28,974, 28,996 (published May 10, 2016) (the “Final Deeming Rule”).
Cigar tobaccos, like cigarette tobaccos, have defined categories (such as dark air-cured and sun-cured tobaccos). Within each of the categories are numerous sub-types such as Sumatra, and Jatim), and varieties (such as Vuelta Abajo). Unlike cigarette tobaccos, cigar tobaccos have little to no standardization and are typically local varieties produced from suppliers and even farm-based selections. Unlike cigarette tobaccos, there are limited varieties produced through any type of seed certification process. So, though the total number of cigar tobacco varieties is much lower than that of cigarette tobaccos, standardization is significantly lower for cigar seeds and the range in seed sub-types and varieties is much greater (3, 4). In addition, the soil and climate conditions of the growing area are significant factors impacting variability of cigar tobacco physical and chemical properties (5). Knowledge of the relationship between the different types of soil, climate and the varieties of crops allows tobacco breeders to produce and distribute seeds specifically adapted to specific growing locations. For example, LUNDH affirmed that the strength, elasticity, thickness and shining quality of cigar wrappers strongly depends on the type of soil and climate in which the tobacco seed is planted. He claimed that even when Nicaraguan seed is planted in Ecuador, the tobacco wrapper produced is very different from a native Nicaraguan wrapper. He explained that the humidity from the constant cloud cover in Ecuador yields firm and elastic wrappers while the volcanic soil type in Nicaragua yields wrappers that are less elastic (6).
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The effect of soil nitrogen content has been shown to impact certain quality attributes of Kentucky dark fire-cured tobacco. S
Another research group led by B
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There has been significant research conducted in the area of Crop Protection Agents (CPAs) specifications and application in tobacco farms as well as Good Agricultural Practices (GAP). V
In 2017 the CORESTA Agro-Chemical Advisory Committee (ACAC) developed and documented various trials performed by different companies across the globe to standardize and mandate specific Cigar Guidance Residue Levels (C-GRLs) for dark air-cured tobacco. Some of the mandates for farmers included strictly controlling fertilization of the soil, proper leaf variety selections, systematic curing strategies, proper topping and suckering as well as optimizing the fermentation process of the cigar leaves. To further bolster the standardization initiative, CORESTA also launched the Agrochemical Residue Field Trials Task Force (RFT-TF) which focused on the development of new agrochemical candidates for setting GRLs in terms of leaf quality and integrity to draw clear distinction between cigar leaf and cigarette tobacco leaves. The task force compared the yields and CPA residues data at different stalk positions between two crop protection programs (the local one, normally based on CPA application relative to when the pathogen is present and the worst-case scenario based on weekly CPA applications), to confirm which was the most effective for eradication of the three main fungal and insect-related tobacco diseases (15).
Differences in conventional cigarettes typically result from variations in tobacco blends and relatively small variations in cigarette construction and physical dimensions such as length, diameter and pressure drop (16). In the case of cigars, the physical parameters vary greatly within and across product categories. In fact, there are several categories of cigars; each consisting of tobaccos that are unique and different from each other. The two major categories which are premium and machine-made cigars (MMCs) are discussed below.
“Premium”, handmade, hand-rolled, (or long-filler) cigars consist of whole tobacco leaves that, when rolled, run the length of the cigar. Long-filler cigars are of a higher quality than short-filler or medium-filler cigars and tend to burn for a longer time. Most “premium” cigars are made entirely of long-filler tobacco, wrapped in a quality natural tobacco binder and wrapper. Tobacco is sorted, bunched, rolled, molded, and pressed by hand. Finally, the outer wrappers are added. During quality control evaluations, cigars are color matched for packaging (3).
Figure 2 shows a premium cigar design with sections labelled using typical vocabulary while Figure 3 shows the layers/parts of tobacco leaf used for making cigars (17, 18). Typically, the premium cigar body is composed of the wrapper (outer tobacco), binder, and the filler (inner tobacco). Generally, the wrappers are harvested from plants cultivated under shade (shade grown tobacco) whereas the fillers and binders are cultivated under full sunshine (sun grown tobacco). The binders are leaves selected from the lower part of the tobacco stem and should be wide, large, and undamaged as possible. During manufacturing, the binder is rolled around the filler leaves and are together referred to as the bunch. The filler leaves are composed of three proportions or varieties (from bottom to top positions of the stem, respectively) namely, volado (filler itself, which mainly contributes to combustibility), seco (dry, mainly contributes to aroma), and ligero (light, mainly contributes to strength). During the cigar hand rolling formulation process, the ligero leaves are sandwiched between the volado and seco leaves (7, 19). The wrapper leaf which is finally wrapped around the bunch must have excellent pliability and elasticity.
Figure 4 (a) shows the art of hand-made premium cigars and (b) an ideal cigar wrapper (15). It is reported and putative that the filler contributes about 85% of the total cigar weight, the binder 10%, and the wrapper the remaining 5% (20).
MMCs cover much more of a range in design complexity and variables compared to premium cigars. The two broad sub-categories are large filter (short-filler) cigars and Medium-Filler cigars. Large filter (or short-filler) cigars are MMCs that consist of chopped up tobacco leaves, which are then rolled into cigars and have a conventional acetate filter applied.
The tobacco in this category of cigars often comes from pieces of the leaf that have been discarded during the process of rolling “premium” or long-filler cigars. Large filter cigars tend to burn hotter and quicker than their long-filler counterparts. By using short-filler tobacco and machines to aid in the cigar rolling process, manufacturers can substantially increase the volume of production relative to a hand-made long-filler cigar.
Medium-filler cigars are MMCs that consist of tobacco leaves, which are chopped into pieces larger than short-filler. Typically, tobacco used in the head and body may differ for an MMC product. These cigars may differ greatly in parameters such as diameter, length, and shape. These variables impact the combustion products, generation of water, variation within cigars, and air flow within the different cigar products.
Due to these broad design variables for both MMCs and hand-made cigars, the standardized smoking regime was developed to maintain a constant airflow through the cigar during machine smoking rather than a constant puff volume as has been specified with standardized cigarette smoking (21).
Much of the recent analytical research for cigars has been designed as a comparison to conventional cigarette results. Some research has been focused on smoking perception but much of the work has been in the area of comparing analytical content and yield or product variability. Two notable differences with regard to cigar smoke are (i) cigar smoke tends to be more alkaline than cigarette smoke and (ii) tobacco commonly used for cigars contains lower levels of reducing sugars than the rapidly dried varieties of tobaccos commonly used in cigarettes. Normal mouth (buccal) saliva is known to be neutral or slightly basic. The impact of the higher alkalinity of cigar smoke (pH 8.5) on nicotine absorption has been studied by A
Comparison of some selected components in the tobacco of cigars and four cigarette tobacco types (% of dry weight of tobacco) adapted from H
Component | Cigar | Tobacco type used for cigarette | |||
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Burley | Maryland | Bright | Oriental | ||
Nitrate | 1.4–2.1 | 1.4–1.7 | 0.9 | <0.15 | < 0.1 |
pH | 6.9–7.8 | 5.2–7.5 | 5.3–7.0 | 4.4–5.7 | 4.9–5.3 |
Reducing sugars | 0.9–2.7 | 1.5–3.0 | 1.2 | 7.0–25.0 | 5.5 |
Total polyphenols | < 0.1 | 2.0 | 1.6 | 5.1 | 4.5 |
Nicotine | 0.6–1.7 | 2.0–2.9 | 1.1–1.4 | 1.2–1.9 | 1.1 |
Paraffins | 0.3–0.32 | 0.34–0.39 | 0.34–0.41 | 0.24–0.28 | 0.37 |
Neophytadiene | 0.4–0.8 | 0.4 | 0.4 | 0.3 | 0.2 |
Phytosterols | 0.14–0.16 | 0.3–0.39 | 0.38 | 0.3–0.45 | 0.26 |
Citric acid | 5.5–6.0 | 8.22 | 2.98 | 0.78 | 1.03 |
Oxalic acid | 3.3–3.6 | 3.04 | 2.79 | 0.81 | 3.16 |
Maleic acid | 1.5–1.8 | 6.75 | 2.43 | 2.83 | 3.87 |
Table 2 identifies differences between selected volatile components in the smoke of cigars, little cigars, and cigarettes. The concentrations of nitrogen oxides (NOx) are significantly higher in cigar smoke compared to cigarette. This is attributed to the elevated nitrate content of the cigar tobacco, the incomplete combustion, and the naturally low porosity of cigar binders and wrappers (25). In contrast, the ammonia content of cigar smoke is more than three times less than the amount in cigarette smoke. The sources and physical attributes (e.g., full length, filler length, weight, etc.) of the cigars and cigarettes used in the above study are defined in a previous investigation by H
Components in the gas phase of mainstream smoke of cigars and cigarettes, values are given for 1.0 g tobacco smoked adapted from H
Component | Cigars | Non-filter cigarettes | Little cigars | Filter cigarettes |
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Carbon monoxide (mg) | 39.1–64.5 | 16.3 | 22.5–44.9 | 19.1 |
Carbon dioxide (mg) | 121–144 | 61.9 | 47.9–97.9 | 67.8 |
Nitrogen oxides (NOx) (μg) | 159, 300 | 160 | 45, 150 | 90–145 |
Ammonia (μg) | 30.5 | 95.3 | 200, 322 | 98 |
Hydrogen cyanide (μg) | 1,035 | 595 | 510, 780 | 448 |
Vinyl chloride (ng) | n.a. | 17.3, 23.5 | 19.7, 37.4 | 7.7–19.3 |
Isoprene (ng) | 2750–3950 | 420, 460 | 210, 510 | 132–990 |
Benzene (μg) | 92–246 | 45, 60 | n.a. | 8.4–97 |
Toluene (μg) | n.a. | 56, 73 | n.a. | 7.5–112 |
Pyridine (μg) | 49–153 | 40.5 | 61.3 | 27.6, 37.0 |
2-Picoline, μg | 7.9–44.6 | 15.4 | 17 | 14.8, 15.6 |
3- + 4-Picoline (μg) | 17.9–100 | 36.1 | 32.9 | 12.6, 20.2 |
3-Vinylpyridine (μg) | 7.0–42.5 | 29.1 | 21.2 | 102, 192 |
Acetaldehyde (μg) | 1020 | 960 | 850, 1390 | 94.6 |
Acrolein (μg) | 57 | 130 | 55, 60 | 87.6 |
n.a. | 16.3–96.1 | 555 | 7.4 | |
n.a. | 13.8–50.7 | 24.5 | 6.6 |
n.a.: data not available
While testing of cigar smoke is more akin to
On the other hand, many of the recent tobacco studies have focused on understanding content and variability of analytes of regulatory concern. Typically, this is with an underlying objective of determining relevance and feasibility of routine Harmful and Potentially Harmful Constituent (HPHC) testing for this product category.
For example, L
It is interesting to note that the difference in nicotine concentration between 2013 and 2014 was 89% whereas the difference in the same analyte between 2014 and 2015 was a nominal 2%. As discussed earlier, this researcher found marked differences in tobacco analyte content in a study wherein the same seed was planted in the same crop year by different near-by farms (4). W
For example, nicotine ranged from approximately 8.3 mg/g to approximately 30 mg/g. However, more interesting findings from the study were that the reported values from the different laboratories for the same samples were in some cases different enough that, in a blind study, one may conclude the results were from different samples. For example, for Sample F, the tobacco NNN values reported by Laboratory 1 and Laboratory 3 were in a similar range at 1748 ng/g and 2050 ng/g, respectively. Laboratory 2 reported a value of 4497 ng/g for the same sample batch, which was more than twice that of the other labs. The differences in standard deviation of the nicotine values between the laboratories were particularly conspicuous with %RSD values of 0.8%, 14%, and 4% for Laboratory 1, 2, and 3, respectively. This supports the essence of current initiatives to increase standardization of testing, including a validated, internationally recognized methodology. Other reported studies on tobacco constituents are consistent with these findings. They include investigations by K
Some researchers have focused attention on physical parameters as a direct and practical measure of product variability. Testing for weight and length is relatively inexpensive with high throughput and low measurement variability.
Testing for diameter and pressure drop may be less reliable given the range of product designs and lack of standardization for measurement technology; it is advisable to limit comparisons of results for these measures between products of different design and/or between laboratories using different analytical methodology.
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There is a rich body of literature, inter-laboratory studies, and significant hands-on experience for testing constituents of conventional cigarettes. For example, standard validated ISO methods for analyses of polyaromatic hydrocarbons (PAHs) tobacco-specific nitrosamines (TSNAs), polyaromatic amines (PAAs), ammonia, chlorides, volatile organic compounds (VOCs), “tar”, nicotine, and carbon monoxide (TNCO) and metals in conventional cigarette smoke are well-documented, established across the tobacco industry, and in use in ISO-accredited third party labs. In addition, several cigarette smoking regimes (ISO, HCI, Massachusetts, CORESTA) and cigarette references have been established, beginning as early as the 1960s (44). In contrast, expertise and standardization with cigar HPHCs testing is substantially limited. For instance, there is a standardized puffing regime and handling requirements (described in CORESTA Recommended Methods (CRM) 64 and 65) (21, 45), but application of that regime to cigars for constituents beyond “tar”, nicotine, and carbon monoxide (TNCO) methods needs optimization for both method development and testing consistency across labs. Within the past decade, study designs, presentations, and publications have revealed the challenges encountered and strides achieved in cigar testing method development. The challenges include optimization of smoke holder accessories needed to accommodate different cigar sizes, lack of in-house method development for cigar analysis and inter-lab proficiency studies for both MMC and premium cigar products.
Recent reports related to analytical testing of cigar smoke have focused on understanding yield differences across the product category, often in comparison to conventional cigarettes, inherent variability of smoke analytes, and challenges with regard to smoking parameters and technology.
W
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For cigars, the CORESTA regime produced the highest HPHC variability while the ISO regime recorded the highest HPHCs variability amongst cigarettes.
Y
Carbonyl yields in cigarillo and leaf-wrapped cigar products tested in 2016 and 2017 under CRM 64 smoking regimen (n = 7) adapted from Y
Tobacco Product Brand Name | 2016-Carbonyl yields, mean (RSD) | 2017-Carbonyl yields, mean (RSD) | ||||||
---|---|---|---|---|---|---|---|---|
Tobacco product weight (mg/unit) | Form-aldehyde (μg/unit) | Acet-aldehyde (μg/unit) | Acrolein (μg/unit) | Tobacco product weight (mg/unit) | Form-aldehyde (μg/unit) | Acet-aldehyde (μg/unit) | Acrolein (μg/unit) | |
Cheyenne Cigarillo Dark & Mellow (SM) | 2462 (6) | 11.6 (16) | 1015 (8) | 20.2 (22) | 2688 (4) | 8.9 (12) a | 1246 (16) a | 14.2 (54) |
Cheyenne Cigarillo Dark & Sweet (SM) | 2354 (8) | 10.2 (14) | 1258 (12) | 21.8 (21) | 2806 (3) | 9.8 (20) | 1333 (13) | 16.2 (25) a |
Dutch Masters Cigarillo (SM) | 2484 (9) | 16.7 (34) | 2232 (9) | 46.2 (30) | 2879 (9) | 9.8 (16) a | 2259 (23) | 23.1 (32) a |
Game - Black (SM) | 2161 (8) | 16.3 (25) | 1681 (10) | 33 (22) | 2363 (6) | 12.1 (22) a | 1817 (14) | 30.8 (30) |
Swisher Sweet Cigarillos - Sticky Sweet (SM) | 2277 (5) | 13.1 (11) | 1551 (11) | 33.6 (18) | 2794 (2) | 10.7 (17) a | 1571 (19) | 22.5 (41) a |
Swisher Sweet Cigarillos (SM) | 3048 (14) | 16.1 (19) | 1926 (10) | 15 (43) | 2682 (3) | 12.9 (22) | 1889 (15) | 36.2 (31) a |
Swisher Sweet Cigarillos - Black (SW) | 2457 (3) | 9.8 (24) | 1548 (9) | 25.7 (36) | 2676 (3) | 9.3 (18) | 1799 (31) | 20.7 (55) |
Dutch Masters President (LG) | 7538 (3) | 11.8 (12) | 4855 (7) | 49 (16) | 7603 (5) | 16.3 (9) a | 3913 (17) a | 34.5 (22) a |
Phillies Blunt (LG) | 6611 (6) | 9.6 (15) | 3152 (4) | 35.8 (25) | 6931 (4) | 19.8 (18) a | 4145 (20) a | 64.6 (33) a |
Diameter at 15 mm: SM = 9–10.5 mm, SW ≤ 8 mm, LG = 15–16.5 mm
indicates statistically different constituent yield for the tobacco product analyzed in 2016 and 2017 (p < 0.05)
The variability of tobacco-specific nitrosamines (TSNAs) which occurs during flue-curing and air-curing of cigar dark tobacco has been a contentious public health debate and well-studied. Cultivation of dark air-cured requires high quantity of fertilizers in nitrate NO3− form, which produces high concentration of this polyatomic anion in cured leaves. According to BUSH and coworkers, during curing the aerobic conditions cause the reduction of the nitrates to nitrites (NO2−) which then react with the secondary alkaloids within the tobacco leaf to form the TSNAs (47). R
Another source of variability within this product category is sampling. The significance of monitoring analytes in cigar tobacco via product sampling and sample size considerations cannot be overemphasized. B
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Several researchers have reported findings that shed light on the challenges of analytical cigar smoking. These include conditioning protocols for cigar products, the effects of lighting technique on smoke constituents, number of relights, effects of ash removal, and the complexity of choosing a proper cigar holder (56, 57, 58).
Continued refinement and extension of standard analytical methods and techniques along with establishment of reference products is the primary response to these challenges (21, 45). Specific analytical methods and validation protocols for cigars need to be developed. Listed in Table 4 are a summary of results for several studies which focused on testing of constituents in cigar tobacco leaf and smoke which could be adopted or further developed (59, 60, 61, 62, 63, 64, 65). Several researchers have investigated the feasibility of extension of cigarette smoking methods for use with cigars, but this work has only confirmed the need for cigar-specific smoking methods. For example, the CORESTA Tobacco and Tobacco Products Analysis (TTPA) and Smoke Analysis (SA) Sub-groups have formally taken this as a primary approach to CRM development (66). P
Selected analytical methods previously applied to testing of cigar leaf and cigar smoke constituents.
Sample analyzed | Constituent and method of determination | Method feasibility with existing equipment | Detection limit |
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Tobacco (1.0 g) from cigarettes was placed into a 20-mL head-space vial. Internal standard solution (2 μL of 1 μg/μL 2,6-dichlorotoluene) and flavor spike mixture (1 μL of 1 μg/μL each benzaldehyde, tetra-methylpyrazine, methanol, and anethole in ethanol) were added. The samples were sealed and allowed to equilibrate for 2 h at room temperature before analysis (59) | Flavor additives to tobacco (e.g., menthol, anethole, benzaldehyde, and tetramethylpyrazine) |
Feasible but could be very tedious, time consuming & unproductive | Benzaldehyde = 66 ng/g |
10.0 g tobacco sample was added to 40 ml dichloromethane. Then the mixture was shaken overnight and steam distillated for 3 h to obtain 800 mL aqueous solution of volatile components using a simple apparatus (60) | Lactones, benzaldehyde, 6-methyl-2-heptanone, 2,4-dimethyl-1-penten-3-one, etc. |
Feasible but could be very tedious, time consuming & unproductive | Total detected 315.72–445.48 μg/g |
Evaluation of volatiles from flue-cured tobacco varieties, smoke organoleptic (61) | Lactones, benzaldehyde, 6-methyl-5-hepten-2-one, etc. |
Distillation system must be available | 200–600 μg/g |
Smokeless tobacco products including snuff, plug tobacco, chewing tobacco, pellets, and snus (62) | α- and β-angelica lactones |
Feasible. However, reference standards for β-angelica lactone unavailable or difficult to obtain | The limit of detection was 30 ng/g and limit of quantitation 65 ng/g with a variability of 9–44% (RSD) |
Tobacco samples used for analysis were Brazilian flue-cured, Kentucky Burley, |
Benzaldehyde, 6-methyl-5-hepten-2-one, acetone, hexenal Chromatography-mass selective detection-flame ionization detection (PT-GC-MSD-FID) hyphenated technique with purge-and-trap-gas | Feasible with little modification | Semiquantitative and qualitative analysis |
Qualitative and quantitative analysis was developed and validated for volatile flavour components in flue-cured tobacco (64) | Flavour components in flue-cured tobacco (e.g., pyridine, 6-methyl-5-hepten-2-one, benzene acetaldehyde, benzaldehyde, furfural) |
Feasible but must have TOF-MS on scope | 5.7–147.6 ng/g |
Determination of selective phenolic compounds in cigarette and MMC cigar smoke (65) | Phenolics (e.g. hydroquinone, resorcinol, phenol, catechol, and |
Feasible high throughput method that is based on CRM 78, which has a run time of 10 minutes | Quantitative and qualitative analysis |
Studies are currently underway to evaluate cigar tobacco leaves and smoke tested for HPHCs typically applied to cigarette and/or smokeless tobacco testing like carbon monoxide analysis, smoke nicotine, selected carbonyls, VOCs, tobacco nicotine, tobacco ammonia, TSNAs, PAAs, and polyaromatic hydrocarbons. A typical example is CORESTA Project 198 which is a collaborative study to analyze BaPs and TSNAs in cigar smoke (70). For smoke measurements, CORESTA recommended and ISO methods for conditioning, smoke collection, and TNCO analysis of cigar tobacco products as described in CRM 64 and CRM 65 have been employed. Details from these analyses, along with information regarding challenges associated with testing across a range of cigars have fairly been investigated.
Another concern is that although there is availability of multiple reference cigarettes, internationally approved cigar testing/smoking references or monitors have not been established.
Fortunately, a project led by an industry team and the University of Kentucky in collaboration with CORESTA and accredited tobacco testing facilities to develop cigar monitors/references was completed in 2019 to fill this gap. A set of reference products, described in Table 5, were formulated with different tobacco composite blends and with varying design features that can represent most of the cigar shapes and sizes (71). The university has developed and marketed several tobacco references, including RT6, a flavored cigar ground filler, and RT8, an unflavored cigar ground filler (72). The University of Kentucky was recently awarded a U.S. federal grant to develop a set of certified reference products (73). Nonetheless, until this project is completed, gaps will exist in the literature for the definitive comparison of physiochemical composition of cigar tobacco leaf and smoke constituents. Additional studies related to analysis of cigar smoke in the recent past include work by D
Cigar reference products available through the University of Kentucky (72).
Reference cigar | Product type | Cigar diameter (mm) | Cigar length (mm) |
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1C1 | Large machine-made cigar | 15.9 | 136.5 |
1C2 | Machine-made filtered cigar | 7.8 | 99.0 |
1C3 | Small machine-made cigarillo | 11.0 | 109.5 |
1C4 | Large machine-made natural wrapper | 12.8 | 103.0 |
World-wide tobacco regulation is in various stages of implementation along different strategic pathways. Typically, cigars represent a small fraction of a country's tobacco market and have been a much lower priority for regulatory actions than cigarettes. In most countries that have implemented regulations, the focus has been on physical measurements, ingredient and marketing reports. In the USA, the FDA has taken an approach similar, though delayed, to the approach taken for cigarettes. FDA regulation of cigarettes and smokeless tobacco products began in 2009 (79). Over time, an expanded list of recommended HPHCs for those products has been established. As previously noted, in 2016, the FDA published a Final Deeming Rule extending its regulatory scope under the Tobacco Control Act to all other tobacco products, including cigars (80).
Once FDA publishes final guidance relating to HPHC testing, the Final Deeming Rule as written will require stand-alone HPHC testing data for cigars. While stand-alone testing may be required for these products under the Tobacco Control Act, the challenges discussed herein related to the variability inherent to cigars make testing for comparative purposes unreliable. Accordingly, researchers consistently urge caution against use of any such analytical testing data as metrics for product comparisons in the context of substantial equivalence review.
For instance, with regard to HPHC testing, LONG recently enumerated the challenges associated with the proposed FDA objective to use HPHC data as an analytical rubric to determine the substantial equivalence (SE) for cigars. He elaborated on an extensive study carried out by Tabacalera USA (TUSA) using 91 premium cigars of 43 different sizes and 18 different blends of dark air-cured tobacco, wherein they inferred that almost all the 36,000 data points generated were statistically misleading, inconclusive and disclosed the immeasurable variability that existed even between cigars of the same size as well as cigars made from the same tobacco composite blends (81). In general, researchers emphasized that, based on the relatively high inherent variability of many analytes with unknown factors, it is advisable to avoid cigar comparisons using HPHC testing (4, 81).
First and foremost, researchers and regulators must understand that there are certain challenges with this product category that will always be a consideration for study design, data analysis, and evaluation of data across the product category. The inherent variability of cigar tobacco due to uncontrollable agricultural considerations, along with variability of the seed genome, and product construction cannot be mitigated with analytical controls or method standardization. That said, there are many active and potential opportunities in this area of testing.
For example:
Establishment of ISO standardized analytical methodologies for appropriate measures and analyses to properly characterize cigars and cigar smoke across the spectra of designs, Full characterization and consistent use of recent and pending reference cigars and cigar tobaccos for surrogate characterization studies, aging studies, and method or laboratory comparisons, Increasing standardization with regard to smoking equipment, physical parameter measurement requirements, cutting and measurement standards, lighting and relighting techniques, Continued evaluation of the approach for collecting mainstream smoke as applied to all cigar categories to account for the significant differences in design parameters. For example, design parameters like circumference, length, mouthpiece-type, diameter determination of cylindrical Improvements to conditioning and storage requirements to allow greater consistency between laboratories, and Establishment of data reporting norms that allow for consistent data analysis across the product category.
To address the challenges above, several approaches have been undertaken, or are currently underway. In the absence of standardized testing specific for cigars, several contract testing laboratories have chosen to incorporate in-house developed cigar methods into the scope of their ISO 17025 accredited methodologies for tobacco product testing. The salient risk in these scenarios would be how to track cigar testing as well as how to account for inter- and intra-laboratory data/report reproducibility or uncertainties over time. Within CORESTA, several active working groups are addressing these challenges for all cigar products. The CORESTA active working groups acknowledge that there are many different types of cigars and that one testing methodology will not be appropriate for all cigar products. For example, the CORESTA Cigar Smoking Methods Subgroup is currently documenting and publishing the technical reports and technical guidelines associated with the TNCO testing of a variety of cigar products (82). In addition, three CORESTA Recommended Methods (CRMs 46, 64, and 65) for conditioning and collection of smoke from cigars have been revised to more accurately reflect technology capabilities and applicability to a wider range of cigar products (21, 45, 83). Further, a CORESTA project to specifically address challenges for testing handmade long-filler cigars has recently been concluded. Lastly, the CORESTA SA Sub-group and the TTPA Sub-group are both actively seeking opportunities to include cigars in inter-laboratory proficiency studies as capabilities to enable standardized and uniform testing across all laboratories. The TTPA Sub-group has brought cigars into scope for nine tobacco methods with additional methods expansions in progress (84). The SA Sub-group has recently completed its first joint experiment for cigar smoke constituents and has established a long-term plan for cigar CRM development (85). The University of Kentucky has established plans to expand the scope of their proficiency testing program to include cigar testing (71, 73)
This review provides a summary of recent analytical research in the area of cigar testing. Undeniably, relative to cigarettes, there is much less research on cigars, hence challenges envisaged with analytical testing of cigars remain to be addressed thoroughly. Especially with regard to the substantial variety between same cigars and cigars of different brands as well as tobacco leaves of different origin, year of harvest and/or method of cultivation. However, there is consistency in the findings reported herein, which underscores the fact that cigars have a very high inherent variability which leads to a very wide range of agricultural yields.
There has been significant on-going activity with regard to cooperative methods of development and standardization. Recent successes in this area have included establishment of a set of reference cigars, establishment of guidance for hand-made cigar testing, and strategies for expansion of scope for standard or accepted methodology specific to cigars. With regard to regulatory oversight, researchers recommend against using HPHC testing for product regulation, comparison, and characterization due to the high inter- and intra-product variability. Physical parameters and ingredient reports seem most practical metrics for product comparison given the high complexity and inherent variability of the product category along with the relatively immature foundation of analytical standardization.
While the studies reviewed in this manuscript highlight an increase in the volume of research associated with cigar testing, additional standardization and cooperative testing is needed to establish a true foundation of analytical understanding of this product category.