Acaricidal Efficacy of Diatomaceous Earths on Different Life Stages of Acarus siro L. and Tyrophagus putrescentiae (Schrank).

Evaluation of three German enhanced diatomaceous earth formulations for the management of two major storage pests in Ghana

Three diatomaceous earths (DEs), InsectoSec®, Diatomeenerde Probe-A and Fossil Shield® 90.0, were tested in the laboratory against Callosobruchus maculatus (Coleoptera: Chrysomelidae) from Ghana. Application rates on stored cowpea were 0.05%, 0.1%, 0.2% and 0.3% wt/wt. Adult mortality was recorded after 13–16 d, progeny production after 6 weeks. InsectoSec® was most effective towards adults, followed by Fossil Shield and finally Diatomeenerde. The highest dosages of the three DEs showed no difference in effectiveness on the 14th day, while InsectoSec® and Fossil Shield® were more effective than Diatomeenerde at the lower dosages. For InsectoSec®, the LD50 and LD90 values were 1.1% and 31.8% wt/wt, respectively, whereas Fossil Shield® recorded LD50 and LD90 of 1.0% wt/w and 13.2% wt/wt, respectively. Grain treated with InsectoSec, Fossil Shield and Diatomeenerde recorded less than 4%, 4% and 11% of C. maculatus progeny of the untreated control, respectively; dosage had no effect on the number of progeny. The potential of using diatomaceous earth to control C. maculatus and other major storage pests in Ghana is discussed.

The present study examined the morphological and physiological effects of amorphous diatomaceous earth against the stored product pestsS. granarius, T. molitor andT. confusum. Diatomaceous earth, namely Fossil Shield® and Dryacide® increased the mortality rate of this insects. After contact with Fossil Shield® the individuals ofS. granarius had significant lost of weight and reduced their water content respectively. This showed that silica dusts break the water barrier of the cuticle. However, it increases the transpiration rate of water across the cuticle and the insect died past several times through dehydration. As well, an addition of food affected the effectiveness of dusts against insects. A lot of stored product beetles will be able to produce metabolic water of feed substrates. This ability protects and weaves contrary to the loss of water. Diatomaceous earth’s can be effective primarily through the sorptive properties of the hygroscopic particles. One day after dust treatment a significant weight loss ofT. molitor pupae was recorded. The exposure to the silica dust Fossil Shield® caused partly an incomplete metamorphosis and death of the individuals. Pupae dipped in Fossil Shield® or abrasive aluminium dust and rolled for further five minutes, reduced not significant higher their weight as unrolled exuvial stages. The morphological analyses of treated insects under the Scanning Electron Microscope showed, that the dust covered the hole integument. Partly, the silica particles sunk into the cuticle. After application of Fossil Shield® at the cuticle of adults,T. molitor, did not show any wax layer. Also it could not be found once blocked by stigma of the mealworm. The dust particles accumulated around the respiration openings and they partly overgrew.

The pulse beetle, Callosobruchus maculatus F. is a key pest to stored Kersting’s groundnut, Macrotyloma geocarpum Harms. There are many reports evaluating various diatomaceous earths (DEs) against stored product pests, but there is limited information on the efficacy of these materials against C. maculatus and none on Kerstings groundnut. Laboratory experiments were conducted to evaluate the efficacy of the DEs, Diatomenerde, Probe-A, Fossil shield, and Damol-D1 against C. maculatus in seeds of M. geocarpum. Each DE was applied at 0.50, 1.00, 1.50, and 2.00 g kg−1, and each treatment infested with newly emerged C. maculatus in petri dishes. The set up was maintained at 50 and 80 % RH regimes at ambient temperature. Data were collected on adult mortality (at 24 h, 48 h, 7 days, and 14 days), oviposition, and progeny emergence of the beetles, and their effects on weight loss and viability of seeds. Probe-A proved the most effective against the beetle, followed by Damol-D1 and Fossil shield. Adult mortality increased progressively with the increasing dosage of DE and exposure time. Seeds treated at 2.00 or 1.50 g kg−1 recorded significantly lower number of eggs and F1 emergence compared with the lower dosages in all DEs. Increased DE concentration consistently decreased seed weight loss due to low beetle infestation, but there was no significant effect on seed viability. DEs were more effective at 50 % RH than at 80 % RH. Probe-A or Damol-D1 applied at 1.50 or 2.00 g kg−1 at 50 % RH is a viable alternative for preventing C. maculatus infestation in stored Kersting’s groundnut.

Action of amorphous diatomaceous earth against different stages of the stored product pests Tribolium confusum, Tenebrio molitor, Sitophilus granarius and Plodia interpunctella

Effects of diatomoceous earth on water content of Sitophilus granarius (L.) (Col., Curculionidae) and its possible use in stored product protectionIncreased problems caused by application of chemical pesticides within pest protection has led to the demand for non‐polluting, biologically specific active countermeasures. This study aimed to test the possible use of diatomaceous earth against Sitophilus granarius. It will also examine the physiological effects of amorphous diatomaceous earth against this insect. After 2 weeks, 100% mortality was observed of the adults treated with 2 g Fossil Shield® per kilogram wheat, at 11–12% corn moisture content and relative humidity of about 62 ± 2%. The rise in grain moisture and relative humidity decreased the effectiveness of the Fossil Shield®. It was observed, that the diatomaceous earth reduced the number of adult granary weevils and increased the mortality rate at development stages, but they did not completely prevent the hatching of the next generation. After contact with diatomaceous earth, the individuals of S. granarius had lost weight and reduced their water content, respectively. The adults significantly lost weight and body water after 1 day exposure to Fossil Shield®. This showed that silica dusts break the water barrier of the cuticle. However, it increases the transpiration rate of water across the cuticle and several insects died through dehydration. At higher relative humidity diatomaceous earth was less effective toward S. granarius, because there was a lower permeability for water across the cuticle. This delays or rather prevents the drying action of diatomaceous earths. Furthermore, the addition of food affected the effectiveness of dusts against S. granarius. A lot of stored product beetles are able to produce metabolic water in the feed substrates. This ability protects them and works contrary to the loss of water.

Diatomaceous earth has been demonstrated in Australia, Germany, and the USA to protect stored products from infestation by insect pests. However, application of diatomaceous earth has rarely been used in Asian countries for the protection of stored grain from insect damage. These facts and the paucity of existing data from the tropics prompted the present study of storage with diatomaceous earth. We exposed rice treated with the diatomaceous earth product Fossil Shield® to infestation by Tribolium castaneum Herbst. During the dry season, when tests were conducted, the mean temperature was 29 ± 2 °C and relative humidity was 80 ± 3 %. The population of T. castaneum in rice was significantly reduced after treatment with Fossil Shield®. Diatomaceous earth at 1 g and 2 g per kilogram rice reduced population growth of T. castaneum to a coefficient of 0.27, and 0.02 respectively after 42 days. Fossil Shield® at 0.5 g per kilogram rice increased the mortality of T. castaneum, but did not stop population growth.

Four silica-based acaricides were examined in laboratory tests for their effectiveness against poultry red mite, Dermanyssus gallinae. All acaricides resulted in 100% mite mortality. Two groups of active ingredients could be differentiated. The products Silicosec® and Ewazid®, based on naturally occurring diatomaceous earth (DE), killed 100% of adult D. gallinae within 48 h exposure time. The time to kill 50% of the mites (LT50) was calculated to be 31.7 and 34.9 h, respectively. The other two products, containing aggregates and agglomerates of pyrogenic synthetic amorphous silicon dioxide as active ingredients, killed the mites in a significantly shorter time: LT50 was 6.3 h for the liquid product Fossil Shield® Instant White and 11.8 h for the powdery product Fossil Shield 90.0 White. This is more remarkable as the quantities of active ingredients used for the DE treatments were several folds higher. The effectiveness of all tested products was also shown in practical tests. A professional company treated five chicken houses on one farm in the Berlin–Brandenburg region with the test products, three houses with Fossil Shield Instant White and one each with Ewazid and Silicosec. Over a period of 46 weeks after stocking, the mite development in the houses was assessed. Only in one of the houses, treated with Fossil Shield Instant White, the mite population remained permanently low. In two houses treated with Fossil Shield Instant White, small mite colonies appeared in week 36, which were controlled by a follow-up spot treatment in week 41. In the houses treated with DE, the first mite colonies appeared 12 weeks after stocking. The number increased continuously over the experimental period and in week 31 after stocking there were clearly visible colonies (2–3 cm diameter) and the first mites could also be detected on the chicken eggs. At this time both houses were treated again with a follow-up spot-treatment, which only led to a slight improvement in one house and to a stabilization of the infestation in the other house. In week 41, large mite colonies were detected in both houses. A spot treatment at this point was ineffective in reducing the infestation. The tests showed faster acaricidal action of the products with the synthetic active ingredients compared to the natural DE-based products. This matches the shorter killing times under laboratory conditions. The experiments in a commercial chicken farm showed that it is possible to control the mite population for a period of 46 weeks by using physically effective SiO2-based products. These products are therefore an effective alternative to the use of chemical acaricides.

Part 1 Biofilms in the food and beverage industries: Biofilms in the food and beverage industries: an introduction Molecular mechanisms involved in biofilm formation by food-associated bacteria Methods for imaging and quantifying the structure of biofilms in food processing and other environments Monitoring of biofilms in the food and beverage industries A centralized database for use in studying bacterial biofilms and quorum sensing in food processing and other environments: MicroBQs. Part 2 Microorganisms and their metabolites in biofilms: Biofilm formation by food spoilage microorganisms in food processing environments Biofilm formation by Listeria monocytogenes and transfer to foods Biofilm formation by Salmonella in food processing environments Biofilm formation by Gram-positive bacteria including Staphylococcus aureus, Mycobacterium avium and Enterococcus spp in food processing environments Biofilm formation by spore-forming bacteria in food processing environments. Part 3 Biofilm prevention, inactivation and removal and beneficial biofilms: Food contact surfaces, surface soiling and biofilm formation Cleaning and sanitation in food processing environments for the prevention of biofilm formation and biofilm removal Novel methods for biofilm control and removal from food processing equipment. Part 4 Biofilms in particular food industry sectors: Biofilms in red meat processing Biofilms in dairy processing Biofilms and brewing Biofilms in poultry processing Beneficial biofilms: wastewater and other industrial applications Biofilms in fish processing Biofilms in fresh fruit and vegetables. Part 5 Appendix: Sampling and quantification of biofilms in food processing and other environments.

The mites found in stored food and house comprise a large group of subclass Acari, belonging to the suborder Acardida of the order Acariformes. They can be found in dust and vacuum samples from floors, furniture, mattresses, Chinese herb al medicine, dry fruit, grain, flour, sugar, and bedding. These mites are nidico lous and feed on organic debris, including sloughed human skin, fungi, spilled food, pollen, etc. These mites are particularly prevalent in Chinese herbal medi cine, dry fruit, grain, flour, sugar, beds, though carpeted floors near beds or couches may also have large numbers. The most common species are Acarus siro, Ty rophagus putrescentiae, Dermatophagoides farinae, D. pteronyssinus, Glycyphagus domesticus, G. Ornatus, Carpoglyphus lactis and Tarsonemus granarius, etc. The viability of mites in storage is quite strong and they can invade and parasitize the intestines of humans[1-15]. They can cause pulmonary acariasis[16-25], urinary acariasis[26-33] and so on. The dejecta of mites is a quite strong allergen and can cause different allergic diseases[34-44]. Intestinal acariasis can be caused by some mites related to the way of diet intake and invading against intestinal mucosa, intestinal muscle [45-58]. The first report of intestinal acariasis caused by these mites was made by Hinman et al[45] (1934). From then on, all kinds of studies on the disease have been reported gradually. In order to make an epidemiological survey of intestinal acariasis the investigation of the disease was taken in so me areas of Anhui Province from 1989 to 1996.

Stored food mites in Czechoslovakia

Evaluation of three organophosphorus insecticides alone and in combination with inert dusts for the control of Trogoderma granarium Everts (Coleoptera: Dermestidae)

Experiments examined the accepted modes of action of the desiccant dust, diatomaceous earth (DE), against the flour mite, Acarus siro (L.) (Astigmata). Adult mites were exposed to three DE products for periods of 3, 18 and 72 h under conditions designed to allow partial desiccation of the mites without causing mortality. After exposure, the DE dust particles were washed off the mite bodies, and both the DE and the mites were examined for presence of cuticular hydrocarbons by gas chromatography-mass spectroscopy (GC-MS) analysis. GC-MS identified seven major cuticular lipids of chain length C(13)--C(26) that may have a role in the waterproofing of A. siro. After 18 h exposure, n-tridecane and several different long-chain fatty acid ethyl esters were detected on one of the DE products. After 72 h, n-tridecane was detected on all three DE products. Mite samples retained after removal of the DEs were examined by microscopy. Tentative evidence was observed by conventional low-power microscopy that might indicate uniform removal of the epicuticle. However, a detailed examination by scanning electron microscopy showed no signs of abrasion.

Listeria monocytogenes is a highly pathogenic foodborne bacteria that is responsible for listeriosis, a serious infectious disease characterized by a high mortality rate among vulnerable populations such as the immunocompromised, pregnant women and the elderly. Moreover, its pathogenicity, its capacity to persist in food processing environments and proliferate in adverse conditions like low temperatures and high salt concentrations, and its ability to generate biofilms make it a major contaminant affecting ready-to-eat food products. In response to this potential public health threat, the agrifood industry has traditionally adopted conventional control methods including thermal treatment and chemical preservatives. However, these approaches have their limitations, especially in terms of efficacy, organoleptic impact and consumer acceptability. In this context, innovative biocontrol strategies are increasingly attracting interest among scientific and industrial stakeholders. This review reports a global overview of the mechanisms involved in the pathogenicity and survival abilities of Listeria monocytogenes in food commodities and processing equipment, as well as a current state of the use of protective cultures and antimicrobial peptides as promising biological-based approaches to control and prevent Listeria monocytogenes in food products and food processing.

Various foodborne viruses have been associated with human health during the last decade, causing gastroenteritis and a huge economic burden worldwide. Furthermore, the emergence of new variants of infectious viruses is growing continuously. Inactivation of foodborne viruses in the food industry is a formidable task because although viruses cannot grow in foods, they can survive in the food matrix during food processing and storage environments. Conventional inactivation methods pose various drawbacks, necessitating more effective and environmentally friendly techniques for controlling foodborne viruses during food production and processing. Various inactivation approaches for controlling foodborne viruses have been attempted in the food industry. However, some traditionally used techniques, such as disinfectant-based or heat treatment, are not always efficient. Nonthermal techniques are considered a new platform for effective and safe treatment to inactivate foodborne viruses. This review focuses on foodborne viruses commonly associated with human gastroenteritis, including newly emerged viruses, such as sapovirus and Aichi virus. It also investigates the use of chemical and nonthermal physical treatments as effective technologies to inactivate foodborne viruses.