Effects of temperature,relative humidity,and protective netting on Tyrophagus putrescentiae (schrank) (sarcoptiformes: Acaridae) infestation,fungal growth,and product quality of cave-aged Cheddar cheese

Research was conducted to evaluate the effects of using food-grade ingredients on cave aged Cheddar cheese as either a surface coating or in nets to prevent infestation by Tyrophagus putrescentiae growth at different environmental conditions. Food grade coating formulations with 1) xanthan gum and propylene glycol (XG+PG) and 2) carrageenan, propylene glycol alginate, and PG (CG+PGA+PG) were made and infused into nets. Jars with cave aged Cheddar cheese cubes that were inoculated with 20 mites were stored in an environmental chamber for 14 d at temperature and relative humidity (RH) combinations of 10, 15, and 20 °C and 75 ± 2 and 85 ± 2% RH. When averaged over RH, mite counts were fewer on control cheese cubes at 10 °C when compared to 15 °C and 20 °C, regardless of whether nets were used or not. However, mites were able to reproduce on untreated cheese cubes at all temperatures. The CG+PGA+PG and XG+PG coatings and nets controlled mite reproduction, as evidenced by harboring less than the initial inoculation level of 20 mites. Sensory results indicated that CG+PGA+PG and XG+PG coated Cheddar cheese at 10 °C and 75% RH and netted Cheddar cheese at 10 or 15 °C and 75% RH did not differ (P > 0.05) from the control with respect to sensory attributes. The treatments at 15 °C and 85% RH and 20 °C caused the cheese to be softer and more bitter than control cheese. In conclusion, the CG+PGA+ 40% PG and XG+40% PG treatments of both coatings and nets inhibited the growth of mites, and the use of nets lessened the impact of food grade coatings on the sensory properties of the Cheddar cheese.     

Biology and integrated pest management of Tyrophagus putrescentiae (Schrank) infesting dry cured hams

The biology and physiology of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), also known as the ham, cheese or mold mite, is reviewed along with methods that have been evaluated for managing and controlling this pest. This review was conducted because the ham mite is an important target pest of the dry cured ham industry. Methyl bromide has been historically used to control mite infestations, but is now banned or being phased out of use in most countries because it is an ozone-depleting substance. Only commercially available stockpiles and quarantine and pre-shipment methyl bromide are available for use in countries that require such action. This review compares the effectiveness and feasibility of recently investigated methods to control mite infestations on dry cured ham and to discuss integrated pest management plans for ham mites. The review also proposes methods for conducting a prevention and monitoring-based integrated pest management program that relies on definitive mitigation such as fumigation only when mite numbers exceed a critical action threshold.     

Efficacy of combining sulfuryl fluoride fumigation with heat to control the ham mite,Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae)

Sulfuryl fluoride (SF) could not control all life stages of Tyrophagus putrescentiae when applied at 23 °C using the highest allowable gas level. Recent work on heat treatments found 40 °C was ineffective against mites unless held for more than 48 h, a heating time that can damage ham quality. The objective of the laboratory trials reported here was to determine the lowest temperature and shortest exposure time at which SF could control mites while staying below the US EPA maximum concentration-time product (CTP) label rate of 1500 gh m⁻³ A 36-h fumigation with a CTP of 1400 gh m⁻³ killed 100% of all mite life stages at 40 °C. Mite eggs, which were determined to be the most SF-tolerant life stage, were exposed to lower CTPs of 300 or 1000 gh m⁻³ SF at 40 °C, control was estimated to require up to 125.71 h at 300 gh m⁻³ and 60.93 h at1000 gh m⁻³. Applying heat with SF just below the maximum allowable CTP will increase the efficacy of this fumigant, but also increases the risk of exceeding the legal limit for the gas. However, at target CTPs of either 300 or 1000 gh m⁻³, which would represent preferred commercial application rates of SF, good levels of mite control could not be achieved at 40 °C within a 48-h exposure.     

Sampling methods to detect and estimate populations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) infesting dry-cured hams

Spatial and temporal dynamics of pest populations are an important aspect of effective pest management. However, absolute sampling of some pest populations such as the ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), a serious pest of dry-cured ham, can be difficult. In this study sampling methods were compared and sampling plans were developed for the ham mite. In one experiment, the number of food-baited traps was maintained at four and the number of mites varied from 500 to 10,000 individuals in environmentally-controlled 18-m² rooms. The number of mites captured in traps increased linearly as the number of mites released increased. Experiments conducted in simulated ham aging rooms suggested that mites preferred the proximal (closer to the pig's body) to the distal side of the ham. The number of mites captured in traps also varied with trap location relative to hams hung from shelves. There were varying degrees of relationships between the number of mites captured in traps and the sampling methods used, such as counts of mites from the storage rack, vacuum sampling of the floor, and ham sampling. Relationships between absolute counts of mites and the number of mites captured in traps or on specific areas of ham were both moderately strong and significant. Two sampling plans were developed for the mite, and it was determined that an economic threshold close to 1 mite per sample unit on the ham can be estimated with 21 and 40 samples at precision levels of 0.35 and 0.25, respectively, or with 10 ham samples when classifying the mite's infestation level as being above or below an action threshold of 0.43. These sampling plans for the ham mite can facilitate the development and evaluation of cost-effective integrated pest management interventions.     

Effects of phosphine and methyl bromide fumigation on the volatile flavor profile and sensory quality of dry cured ham

In separate experiments, randomized complete block designs with three replications were utilized to evaluate the effects of phosphine (PH₃) (0, 200 and 1000 ppm for 48 h) and methyl bromide (MB) (0, 4, 8, 16, and 32 mg/L for 48 h) fumigation concentration on the volatile flavor compound concentrations in dry cured ham. Minimal differences existed (P > 0.05) in the presence and concentration of aroma active compounds in both PH₃ and MB fumigated hams but sulfur and oxidation compounds were more prevalent (P < 0.05) in the fumigated treatments when compared to the control. As phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P < 0.05), but all samples contained levels that are lower than the legal limit of phosphine allowed in stored food products (0.01 ppm) in the United States. A triangle test (n = 56) indicated that consumers could not discriminate (P > 0.75) between the control hams and those that were fumigated with PH₃. Minimal aroma/flavor differences existed among MB, PH3 and control hams, and dry cured ham that was fumigated with PH₃ was safe for consumption based on residual phosphine concentrations in the meat tissue.     

Sulfuryl fluoride fumigation effects on the safety,volatile composition,and sensory quality of dry cured ham

A randomized complete block design with three replications was utilized to evaluate the effects (P < 0.05) of various fumigation concentrations of sulfuryl fluoride (SF) (0, 12, 24, 36 and 72 mg/L) on the fluoride, sulfuryl fluoride, and volatile flavor compound concentrations in dry cured ham. Fluoride and SF concentrations increased (P < 0.05) in dry cured hams as SF fumigation concentration increased, but all samples contained fluoride and SF concentrations below the legal limits of 20 and 0.01 ppm, respectively. Minimal differences existed (P > 0.05) in the presence and concentration of aroma active compounds, but oxidation compounds were slightly more prevalent (P < 0.05) in the 72 mg/ml treatment when compared to the control. A triangle test (n = 54) indicated that consumers could not discern (P > 0.75) between hams that were fumigated with SF at 0 and 36 mg/ml. This study revealed that there were minimal aroma/flavor differences among the ham treatments between 0 and 36 mg/ml, and that dry cured ham that was fumigated with SF was safe and met legal requirements for consumption.     

Acaricidal effect of three zeolite formulations on different life stages of Tyrophagus putrescentiae (Schrank) and Acarus siro L. (Sarcoptiformes: Acaridae)

The mould mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) and the flour mite, Acarus siro L. (Sarcoptiformes: Acaridae) are very common stored-product mites found in a wide spectrum of commodities of both plant and animal origin. In this study, we evaluated three zeolite formulations as stored-wheat protectants regarding the management of larvae, nymphs and adults of T. putrescentiae and A. siro at different exposure intervals, i.e., 1, 2, and 5 days (d), and doses, i.e., 200, 500, and 1000 ppm. We found that the zeolite formulations tested here can be effective for the control of both stored-product mite species. Mortality of all stages of T. putrescentiae and A. siro was considerably affected by dose and exposure intervals, i.e. the higher the dose and the longer the exposure time, the greater the mortality. Nevertheless, 100% mortality was not recorded on any of the life stages and formulations tested, even in the case of the highest dose and the longest exposure interval. All zeolite formulations provided the same efficacy level, which was similar for immature stages and adults of both mite species. The results of the present study suggest that longer exposures of the evaluated zeolite formulations are required to increase the efficacy on the control of T. putrescentiae and A. siro.     

Sulfuryl fluoride as a methyl bromide alternative for fumigation of Necrobia rufipes (Coleoptera: Cleridae) and Tyrophagus putrescentiae (Sarcoptiformes: Acaridae), major pests of animal-based stored products

Sulfuryl fluoride (SF) has been registered in many countries for stored product applications as an alternative to other fumigants, especially methyl bromide (MB). Research was conducted to establish SF fumigation protocols for the mortality of pests infesting post-harvest durable commodities. The efficacy of SF against two major arthropod pests of southern dry-cured hams, the red-legged ham beetle, Necrobia rufipes, and the ham mite, Tyrophagus putrescentiae, was investigated. SF caused significant mortality in ham beetles but not for ham mites when treated for 48 h at 23 °C. Eggs of N. rufipes were more tolerant to SF than other stages fumigated. In addition, early aged (1–2 d old) eggs of N. rufipes were more susceptible to SF than late-aged (4–5 d old) eggs. Furthermore, SF fumigation led to 100% control of larvae, pupae and adults of N. rufipes by 8 g/m³ while the eggs required 20.88–24.72 g/m³ to prevent 100% hatch. However, T. putrescentiae showed high tolerance to SF as it survived concentration-time products in excess of the standard label limit 1500 g h/m³. SF studies also revealed that the eggs of T. putrescentiae were several fold more tolerant than that of the mobile stage, the nymphs and adults. SF trials under pilot-scale commercial conditions were also carried out that further supported the efficacy of SF for red-legged ham beetles but not for the ham mite. SF may not be suitable for managing ham mites based on work to date, but future work could investigate longer exposure times at higher temperatures.     

Effects of packaging method and storage time on the chemical, microbiological, and sensory properties of Turkish pastirma - A dry cured beef product

The effects of packaging method (aerobic packaging (AP), vacuum packaging (VP) or modified atmosphere packaging (MAP)), the form of pastirma (sliced or non-sliced) and storage time (0, 15, 30, 60, 90 or 120 days) on the chemical, microbiological and sensory properties of a Turkish pastirma were investigated. Overall, MAP preserved chemical, microbiological and sensory properties of Turkish pastirma better than AP or VP. Very high correlation coefficients (almost all >0.90) were observed between subjective quality parameters (sensory properties) and objective quality parameters (TBARS, hexanal content, L^*, a^*, and b^*), which suggests that sensory panel was able to determine the quality changes over storage time precisely. Based on the results of this study, MAP should be the preferred choice of packaging in order to preserve overall quality of Turkish pastirma and its implication for pastirma packaging may increase pastirma’s current share in the processed meat product market.     

快大液肥对烤烟生长及产质量的影响

在常量施肥的基础上,苗期和大田期叶面喷施或穴施快大液肥,能改善烟叶生长状况,促使烟苗生长健壮,烟株根系发达,生长旺盛,开片良好,烟叶产量,均价,产值有不同程度的提高;烟叶钾含量增加,含氮化合物下降,刺激性减小,香气增加。