The genus
Long before the arrival of the Spanish colonizers, the breeding of
Within Mayan traditional medicine, honey has been used to treat eye, ear, respiratory, digestive and skin problems (González & Quezada, 2010), to clean the blood in women after childbirth, and a soothing balm for sleeping, among others (Vit et al., 2015). Currently,
According to the
However, since current standards apply to
This manuscript summarises the information regarding the physicochemical parameters and microbial criteria from different
Meliponini honeys have been characterized physicochemically with the same parameters applied for
Values minimum and maximum values of physicochemical parameters for honeys of the genus
Parameters | Min | Max |
---|---|---|
Reducing sugars (g/100 g) | 34.8 | 82.1 |
Fructose (g/100 g) | 29.2 | 59.2 |
Glucose (g/100 g) | 21.8 | 45.7 |
Sucrose (g/100 g) | 0.1 | 9.1 |
Moisture (%) | 17.3 | 45.8 |
pH | 2.8 | 6.6 |
Free acidity (meq/kg) | 1.0 | 120.0 |
Electrical conductivity (μS/cm) | 102.8 | 830.0 |
Ash (%) | 0.01 | 0.6 |
Sugars are mainly responsible for the physical characteristics and chemical behavior of honey. Sucrose content in honey is analyzed to identify any improper handling. High levels may indicate adulterations including the addition of such inexpensive sweeteners as cane sugar, early harvesting indicating that sucrose was not completely transformed into glucose and fructose or prolonged artificial feeding of bees with sucrose syrups (Tornuk et al., 2013). The enzymatic action splits sucrose into mono-saccharide ranging from 65% to 80% of total soluble solids, with fructose (approximately 38.5%) and glucose (approximately 31.0%) being found in higher concentrations. The average ratio of fructose to glucose is 1.2:1, which depends considerably on the source of nectar from which the honey was made (Escuredo et al., 2014; Tornuk et al., 2013). Almeida et al. (2007), reported that from samples collected in Brazil’s Amazon region the average values of fructose, glucose and sucrose were 31.91%, 29.30% and 0.19% respectively for honeys produced by
In 2017, the Malaysian Standards Department, the agency that regulates the sale and distribution of honey produced by stingless bees, published in its quality standards that good quality honey should have a concentration of fructose and glucose not exceeding 85 g/100 g of honey and not more than 7.5 g and 9.5 g of sucrose and maltose, respectively (Abd et al., 2017). With respect to
Oliveira et al. (2017) described how the concentration of reducing sugars for seven meliponas species from Brazil,
Souza et al. (2006) reported that the amount of reducing sugars tended to be higher in
The content of sugars in honey from bees of the genus
Species | Reducing sugars (g/100 g) | Fructose (g/100 g) | Glucose (g/100 g) | Sucrose (g/100 g) | Source |
---|---|---|---|---|---|
66.0 – 76.2 | n.r. | n.r. | 1.1 – 8.3 | Souza et al. (2004) | |
64.3 – 82.1 | n.r. | n.r. | 0.6 – 6.2 | Alves et al. (2005) | |
n.r. | 31.9 | 27.6 | 9.1 | Vit et al. (2006) | |
n.r. | 32.2 | 28.6 | 4.6 | Vit et al. (2006) | |
n.r. | 30.7 – 32.0 | 28.6 – 29.8 | 0.1 – 0.2 | Almeida et al. (2007) | |
53.9 – 57.0 | n.r. | n.r. | 1.1 – 3.2 | Carvalho et al. (2009) | |
60.1 – 60.4 | n.r. | n.r. | 1.3 | Carvalho et al. (2009) | |
68.8 | n.r. | n.r. | 3.5 | Dardón & Enríquez (2008) | |
76.0 | n.r. | n.r. | 1.7 | Dardón & Enríquez (2008) | |
n.r. | 31.8 | 37.3 | 3.2 | Gutiérrez et al. (2009) | |
n.r. | 30.2 | 31.9 | 6.8 | Gutiérrez et al. (2009) | |
n.r. | 29.2 | 21.8 | 4.9 | Almeida et al. (2013) | |
n.r. | 34.1 | 29.3 | 6.5 | Fonte et al. (2013) | |
50.5 – 72.8 | n.r. | n.r. | n.r. | Silva et al. (2013) | |
57.1 – 74. 2 | n.r. | n.r. | n.r. | Moo et al. (2015) | |
57.7 – 61.9 | 31.5 – 34.7 | 26.0 – 29.0 | n.r. | Biluca et al. (2016) | |
54.9 – 69.6 | 30.4 – 39.4 | 24.0 – 31.0 | n.r. | Biluca et al. (2016) | |
60.5 – 70.5 | 33.4 – 40.5 | 26.0 – 29.0 | n.r. | Biluca et al. (2016) | |
65.8 – 69.1 | 36.4 – 38.9 | 29.5 – 30.1 | n.r. | Biluca et al. (2016) | |
65.6 | 35.6 | 30.1 | n.r. | Biluca et al. (2016) | |
62.7 | 36.4 | 26.3 | n.r. | Biluca et al. (2016) | |
63.2 – 71.2 | 50.0 – 59.2 | 37.7 – 45.7 | 0.7 – 3.9 | Sousa et al. (2016) | |
62.7 – 71.2 | 53.6 – 57.6 | 38.1 – 43. 3 | 1.9 – 3.0 | Sousa et al. (2016) | |
52.9 – 81.6 | n.r. | n.r. | n.r. | Gomes et al. (2017) | |
63.4 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
65.6 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
60.6 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
34.8 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
64.2 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
78.9 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
64.2 | n.r. | n.r. | n.r. | Oliveira et al. (2017) | |
65.4 | n.r. | n.r. | 2.1 | Alves et al. (2018) | |
59.0 | n.r. | n.r. | n.r. | Duarte et al. (2018) | |
75.0 | n.r. | n.r. | n.r. | Duarte et al. (2018) | |
75.0 | n.r. | n.r. | n.r. | Duarte et al. (2018) | |
67.0 | n.r. | n.r. | n.r. | Duarte et al. (2018) | |
50.1 – 52.6 | n.r. | n.r. | n.r. | Fernandes et al. (2018) | |
42.9 – 55.6 | n.r. | n.r. | 1.4 – 6.1 | Vale et al. (2018) |
n.r. - Not reported
Water is the second largest component of honey. Its content varies from 15 to 21 g/100 g depending on the botanical origin, the level of maturity reached in the hive, processing techniques and storage conditions (Yücel & Sultanoglu, 2013). The moisture content is one of the most important characteristics influencing the physical properties of honey including viscosity, crystallization, color, taste, flavor, specific gravity, solubility and conservation (Escuredo et al., 2013).
The percentage of moisture in honey also varies in regions with high relative humidity, depending on the rainy season (Karabagias et al., 2014) and therefore on the vegetation. Moguel et al. (2005) reported that honey from trees and vines, mainly leguminous and convolvulaceous, registered during the period from November to December, after the rainy season in the Yucatan Peninsula, presented a higher average moisture (19.2±0.7%) than the Tajonal honey (18.0±0.8%), botanical resource used by bees in the dry season. Moguel et al. (2005) reported that honey from trees and vines, mainly leguminous and convolvulaceous, registered during the period from November to December, after the rainy season in the Yucatan Peninsula, presented a higher average humidity (19.2± 0.7%) than the Tajonal honey (18.0±0.8%) botanical resource used by bees in the dry season.
The moisture percentages of the
Regarding
The moisture content of honey from bees of the genus
Species | Moisture (%) | Source |
---|---|---|
26.8 – 32.0 | Souza et al. (2004) | |
23.1 – 32.5 | Alves et al. (2005) | |
25.3 | Evangelista et al. (2005) | |
31.2 | Bijlsma et al. (2006) | |
32.2 | Bijlsma et al. (2006) | |
24.5 | Vit et al. (2006) | |
28.3 | Vit et al. (2006) | |
24.8 – 30.6 | Almeida et al. (2007) | |
26.0 – > 30.0 | Carvalho et al. (2009) | |
25.2 – > 30.0 | Carvalho et al. (2009) | |
17.3 | Dardón et al. (2008) | |
19.7 | Dardón et al. (2008) | |
20.4 | Dardón et al. (2008) | |
27.2 | Gutiérrez et al. (2009) | |
23.7 | Gutiérrez et al. (2009) | |
22.8 – 36.0 | Lage et al. (2012) | |
24.8 | Almeida et al. (2013) | |
24.0 | Fonte et al. (2013) | |
20.2 – 24.4 | Silva et al. (2013) | |
21.0 – 25.3 | Moo et al. (2015) | |
28.8 – 39.1 | Biluca et al. (2016) | |
25.9 – 43.5 | Biluca et al. (2016) | |
28.3 – 38.2 | Biluca et al. (2016) | |
29.6 – 29.9 | Biluca et al. (2016) | |
27.7 | Biluca et al. (2016) | |
23.4 | Biluca et al. (2016) | |
23.9 – 28.9 | Sousa et al. (2016) | |
24.3 – 26.5 | Sousa et al. (2016) | |
19.2 – 28.4 | Gomes, et. al. (2017) | |
28.6 | Alvarez et al. (2018) | |
29.2 | Alves et al. (2018) | |
30.0 | Duarte et al. (2018) | |
31.0 | Duarte et al. (2018) | |
27.0 | Duarte et al. (2018) | |
30.0 | Duarte et al. (2018) | |
23.7 – 27.2 | Fernandes et al. (2018) | |
25.3 – 27.0 | Grajales et al. (2018) | |
25.0 – 25.8 | Grajales et al. (2018) | |
27.7 – 45.8 | Vale et al. (2018) |
Vit et al. (2004) stablished that a maximum of 30.0 is an adequate percentage of moisture in
Moisture in honey can also increase during harvesting as well as in inadequate storage conditions since honey is hygroscopic and absorbs moisture from the atmosphere (Karabagias et al., 2014). In respect to the water activity (Aw), the honey presents a range between 0.49 to 0.65 (Mossel et al., 2003), which means that it is a product with a long shelf life even without refrigeration, does not require hydration to be consumed and can be considered as microbiologically safe. The Aw values of honey above 0.60 represent a critical threshold for microbial stability (Yücel & Sultanoglu, 2013). Although there are no limits imposed by standards, the Aw value is known to be very important, because honey contains osmophilic yeasts that cause fermentation, forming ethyl alcohol and carbon dioxide, thus changing the quality of the honey (Tornuk et al., 2013; Yücel & Sultanoglu, 2013).
Although the pH limit of honey has not yet been described by any regulatory committee, a natural pH set between 3.2 and 4.5 allows the inhibition of the growth of microorganisms, as the optimum for most microorganisms is between 7.2 and 7.4 (Karabagias et al., 2014). However, the Malaysian Standard (MS 2683:2017) has agreed to set a pH range of 2.5 to 3.8 for stingless bee honeys (Nordin et al., 2018).
The free acidity content is an indirect measure of freshness in honey and expresses the acidity independently of the acids present, which originate from secretions of bees’ salivary glands that carry out the enzymatic and fermentation processes. Three types of acidity can be distinguished in honey: free, lactic and total. The relationship between lactonic acidity and free acidity shows whether honey is of floral or honeydew origin, while total acidity is a sum of the previous ones (Guadalix et al., 2002).
Although more than twenty organic acids have been found to be present in honey, gluconic acid is the most abundant and results mainly from glucose splitting due to the action of the glucose oxidase enzyme. Gluconolactone is produced as an intermediate product in this reaction, which also influences the concentration of acidity (Moguel et al., 2005). This transformation has been observed to be slow in dense honeys and rapid in fluid honeys, and the amount of acid depends on the quality and volume of nectar flow as well as on the time that elapses between its collection and storage (Zandamela, 2008). In the honey subjected to high temperatures, hydroxymethylfurfural (HMF) may be produced through the dehydration of hexose, mainly fructose, which in turn will form levulinic and formic acids when degraded, which will increase acidity levels (ICMSF, 2001).
In thirty-three samples analyzed by Biluca et al. (2016) the observed pH values ranged between 3.33, for
While Vit et al. (2006) described a pH from 3.67 to 4.07 and acidity from 18.90 to 11.83 meq/kg, for
The pH and free acidity of honey from bees of the genus
Species | pH | Free acidity (meq/kg) | Source |
---|---|---|---|
3.1 – 3.4 | 21.5 – 80.5 | Souza et al. (2004) | |
3.2 – 3.5 | 18.5 – 62.5 | Alves et al. (2005) | |
4.7 | 28.3 | Evangelista et al. (2005) | |
4.1 | 11.8 | Vit et al. (2006) | |
3.7 | 18.9 | Vit et al. (2006) | |
3.4 – 4.1 | 20.6 – 27.8 | Almeida et al. (2007) | |
3.5 – 3.6 | 25.7 – 55.0 | Carvalho et al. (2009) | |
3.7 – 6.6 | 6.2 – 28.0 | Carvalho et al. (2009) | |
3.7 | 23.2 | Dardón et al. (2008) | |
3.8 | 4.9 | Dardón et al. (2008) | |
3.8 | 10.6 | Dardón et al. (2008) | |
5.1 | 29.7 | Gutiérrez et al. (2009) | |
5.0 | 29.2 | Gutiérrez et al. (2009) | |
3.3 – 3.8 | 25.0 – 107.0 | Lage et al. (2012) | |
4.0 – 4.5 | 1.0 – 52.0 | Lage et al. (2012) | |
3.2 – 5.7 | 2.1 – 122.5 | Lage et al. (2012) | |
n.r. | 32.5 | Almeida et al. (2013) | |
3.6 | 35.0 | Fonte et al. (2013) | |
2.9 – 3.8 | 24.7 – 59.7 | Silva et al. (2013) | |
2.6 – 3.3 | 13.0 – 71.3 | Moo et al. (2015) | |
3.8 | 63.3 – 139.9 | Biluca et al. (2016) | |
3.3 – 4.3 | 21.4 – 106.0 | Biluca et al. (2016) | |
3.4 – 4.0 | 42.4 – 120.0 | Biluca et al. (2016) | |
3.8 – 6.6 | 16.2 – 106.0 | Biluca et al. (2016) | |
4.2 | 38.2 | Biluca et al. (2016) | |
4.5 | 28.7 | Biluca et al. (2016) | |
3.1 – 5.3 | n.r. | Sousa et al. (2016) | |
3.5 – 4.2 | n.r. | Sousa et al. (2016) | |
2.8 – 3.6 | n.r. | Gomes et al. (2017) | |
3.2 | 41.5 | Alvarez et al. (2018) | |
4.1 | 34.3 | Alves et al. (2018) | |
4.2 | 37.0 | Duarte et al. (2018) | |
4.2 | 17.0 | Duarte et al. (2018) | |
4.6 | 22.0 | Duarte et al. (2018) | |
4.3 | 22.0 | Duarte et al. (2018) | |
3.8 – 4.9 | 27.5 – 30.6 | Fernandes et al. (2018) | |
3.6 – 4.2 | 5.9 – 40.3 | Grajales et al. (2018) | |
3.6 – 4.0 | 55.8 – 85.0 | Grajales et al. (2018) | |
3.0 – 4.4 | 23.8 – 61.5 | Vale et al. (2018) |
n.r. - Not reported
Ash content is a quality measure that evaluates the concentration of minerals present in honey. The mineral content indicates the geographical origin and environmental pollution, since it depends on the type of soil where the vegetation from which the nectar was collected is located (Karabagias et al., 2014). This can be seen in Tab. 5, where values of percentage of ash in honey are presented as low as 0.01% and up to 0.60% for the same species
The electrical conductivity and ash content of honey from bees of the genus
Species | Electrical conductivity (μS/cm) | Ash (%) | Source |
---|---|---|---|
287.5 – 525.0 | n.r. | Souza et al. (2004) | |
267.5 – 462.0 | n.r. | Alves et al. (2005) | |
n.r. | 0.17 | Evangelista et al. (2005) | |
n.r. | 0.02 | Vit et al. (2006) | |
n.r. | 0.13 | Vit et al. (2006) | |
264.2 – 272.1 | 0.18 | Carvalho et al. (2009) | |
226.0 – 445.9 | 0.15 – 0. 40 | Carvalho et al. (2009) | |
n.r. | 0.07 | Dardón et al. (2008) | |
n.r. | 0.06 | Dardón et al. (2008) | |
n.r. | 0.06 | Dardón et al. (2008) | |
150.0 | n.r. | Gutiérrez et al. (2009) | |
140.0 | n.r. | Gutiérrez et al. (2009) | |
102.8 | 0.02 | Almeida et al. (2013) | |
n.r. | 0.03 – 0.20 | Silva et al. (2013) | |
n.r. | 0.01 – 0.60 | Moo et al. (2015) | |
360.0 – 700.0 | n.r. | Biluca et al. (2016) | |
160.0 – 830.0 | n.r. | Biluca et al. (2016) | |
270.0 – 700.0 | n.r. | Biluca et al. (2016) | |
540.0 – 840.0 | n.r. | Biluca et al. (2016) | |
250.0 | n.r. | Biluca et al. (2016) | |
150.0 | n.r. | Biluca et al. (2016) | |
300.0 – 636.0 | 0.04 – 0.52 | Sousa et al. (2016) | |
340.0 – 670.0 | 0.03 – 0.41 | Sousa et al. (2016) | |
n.r. | 0.02 – 0.33 | Gomes et al. (2017) | |
580.0 | 0.46 | Alvarez et al. (2018) | |
391.5 | 0.18 | Alves et al. (2018) | |
700.0 | n.r. | Duarte et al. (2018) | |
500.0 | n.r. | Duarte et al. (2018) | |
600.0 | n.r. | Duarte et al. (2018) | |
300.0 | n.r. | Duarte et al. (2018) | |
500.0 – 660.0 | n.r. | Grajales et al. (2018) | |
450.0 – 620.0 | n.r. | Grajales et al. (2018) | |
277.7 – 513.0 | 0.24 – 0.49 | Vale et al. (2018) |
n.r. - Not reported
Although the
Gutiérrez et al. (2009) reported an electrical conductivity of 150.0 μS/cm for
Almeida et al. (2013) suggests that the maximum permitted value for the electrical conductivity of stingless bee honeys should be 500 μS/cm, which is lower than for
Honey color is an important parameter in quality, acceptance and consumer preference (Da Silva et al., 2016), because it is the result of the different degrees of absorption by honey constituents of the light wavelengths (Fattori, 2004). Color is one of the most variable parameters and depends on the content of minerals, pollen and phenolic compounds (Solayman et al., 2016). The color of honey is related to the formation of a series of brown compounds that originate when the organic matter of honey reacts with mineral salts (Gómez, 2004). Dark honeys contain higher levels of microelements than light honeys (Alqarni et al., 2014), and although the color range of honey in most cases may be from light yellow to amber, dark amber or even black, in some honeys green or red hues may be observed (Abu et al., 2017). Likewise, all honeys gradually acquire a darker coloration due to a set of non-enzymatic browning reactions known as Maillard’s reactions (Can et al., 2015), which are favored by exposure to light, heat and storage time (Sousa et al., 2016).
Nordin et al. (2018) reported that honey with a higher color intensity has been detected in
Fonte et al. (2013) detected an extra light amber color (34.0–50.0 mm Pfund) for
HMF is an indicator of freshness, as it is generally absent in freshly harvested honey and tends to increase over time. HMF is a breakdown product of simple sugars, especially fructose. Several factors affect HMF content, including heating and storage conditions, as well as a honey’s pH and adulteration with simple sugars from an external source (Pasias et al., 2017).
The range of HMF detected values in samples of
Almeida et al. (2013) described that the HMF content in
In some cases, stingless bee honeys are often considered adulterated because of their high HMF content associated with improper handling techniques or adverse weather conditions (Alves et al., 2005). Nevertheless, their HMF content is directly related to their higher natural moisture content. Therefore, a revision of the HMF standard for stingless bee honeys is of utmost importance (Nordin et al., 2018).
The concentration of amino acids and proteins in honey is relatively low, approximately 0.7% (Bogdanov, 2010), and depends on both its botanical and geographical origin as well as its storage time (Abu et al., 2017). Honey contains almost all physiologically important amino acids (Bogdanov, 2010), proline being the most abundant, followed by lysine, glutamic acid and aspartic acid (Cauich et al., 2015).
Almeida et al. (2013) found a significant difference in the protein content of honey produced by
Enzymes are the main protein component in honey added by bees during the honey ripening process (Abu et al., 2017). Diastase (amylase), a relatively heat and storage stable enzyme, splits starch into maltose. Invertase (saccharase or α-glucosidase), primarily catalyzes the conversion of sucrose to glucose and fructose. Other enzymes such as glucose oxidase and catalase regulate the production of hydrogen peroxide, one of the antibacterial factors in honey (Bogdanov, 2010).
Although the diastase and invertase activity present a wide variability they are used as indicators to evaluate the quality of the honey. The diastase activity is expressed as the diastase number (DN) in Schade units or Göthe units and both the
Souza et al. (2006) in a review of scientific articles published between 1964 and 2005 found ranges of 0.9–23.0 for diastase and 19.8–90.1 for invertase in
Honey-insoluble matter includes bee pollen, honeycomb debris, bee and dirt particles, and as such, this parameter is a criterion for cleanliness since it allows the detection of impurities in honeys (Almeida et al., 2013). During the extraction process, the honey may become contaminated with insoluble solids, so it must be filtered so that insect remains, grains of sand, pieces of honeycomb and wax are eliminated. According to the
Few studies have analyzed the content of insoluble solids in stingless honey, which makes comparisons difficult. However, Vit et al. (2016) mentions that for T
In honey, the growth of many microorganisms is limited due to their intrinsic properties such as: high osmotic pressure due to low water activity (0.5–0.65) (Chen, 2019); low pH (average 3.9) due to the presence of organic acids, mainly gluconic acid; the presence of hydrogen peroxide generated by the action of the enzyme glucose oxidase; low protein content; low redox potential due to the presence of reducing sugars; and chemical agents present such as lysozyme, phenolic acids, pinocembrine, terpenes, benzyl alcohol and volatile substances (Rao et al., 2016). The few microorganisms that can develop or remain dormant in honey are derived from primary or secondary sources of contamination. Sources of primary contamination, which are virtually impossible to avoid because they occur naturally, include pollen, honeybee digestive extracts, dust, air, soil, and nectar (Różańska & Osek, 2016). Secondary sources are due to honey handlers and processors, facilities, equipment, and utensils, and are easily controlled through the implementation of good manufacturing practices (GMP) (Kačániová et al., 2009; Grabowski & Klein, 2015; Olaitan et al., 2017).
In Mexico, the current NOM-004-SAG/GAN-2018 (NOM, 2018) does not mention the sanitary quality of honey, but NMX-036-NORMEX-2006 (NMX, 2006) establishes that the presence of a maximum value of 1000 CFU/g of non-pathogenic bacteria and up to 100 CFU/g of yeasts and molds are accepted. The Ministry of Health in Peru established a maximum of 104/g for mesophilic aerobes and 102/g for both moulds and sulphite-reducing aerobes as well as presented a three-class sampling plan for these indicators. The European Microbiological Standard for honey destined for the Spanish market and the European Union established the following: mesophilic aerobes - 104/g, entero-bacteria - absence in 1 g,
Among the sporulating bacteria, spores of
Although honey is a microbiologically safe food, some studies have shown that it contains the presence not only of aerobic mesophilic bacteria, moulds and yeasts, but also of such lactic acid bacteria (LAL) as
There have been few studies on the microbiological characterization of honey from stingless bee and the genus
Similarly, Fernández et al. (2018) reported that all samples of melipona honey obtained from four ecosystems in the municipality of Abreus, province of Cienfuegos (Cuba), complied with the international requirements. All samples presented microbiological characteristics suitable for consumption and marketing, despite the fact that in all ecosystems there was an integration of agriculture-livestock or backyard farming, and in some cases wastewater within the flight range of the bees. The Meliponini tribe interact mutually with microorganisms including acid-lactic bacteria in Australian species such as
Although stingless bee microorganisms are useful to honey beekeepers because they make such products as mead, honey and pollen jelly or a creamy pollen shake (Menezes et al., 2013), little is known about the pathogens in this type of bee (Nunes et al., 2016). However, because honey from these bees is currently used in folk medicine (Vit et al., 2004; Vit et al., 2015) specific parameters must be met to ensure that this product does not endanger the health of those who use it. For example, the Official Gazette of the Republic of Argentina established to
According to the consulted investigations, the honey of the
Studies are limited with respect to the microbiology of the honey of the genus
The sanitary quality of