Measuring the efficacy of sanitation

The 15 studies cited here measure the efficacy of sanitation alone or in combination with other methods such as heat treatment, insecticides, fumigants, insect resistant packaging and semiochemical-based methods (mass trapping, attract and kill, sex pheromone permeation) for management of stored product insects. Early studies were published in the 1950’s at a time when Sanitation Workshops were being organized to strengthen FDA regulations, and others between 1981 and 2021 at a rate of 1 to 4 per decade. Facilities studied included bag storage of rice in simulated warehouse, bulk grain storage on farms and at elevators, flour mills, pet food and grain products areas in retail stores and large sea-going passenger vessel. Cleaning methods ranged for sweeping with broom to vacuum cleaner to pressure cleaning with water. Results ranged from no effect of sanitation alone to very effective alone or with other methods.

Sanitation removes insects and the residual food which may also provide shelter for insects with heat treatments and insecticide applications. See Food on Susceptibility of Stored-Product Insects page for more references on the benefits of food in reducing the susceptibility of insects to pesticides. The number of insects removed by cleaning may be reduced as the number of available hiding places increases. Proper disposal of insects and residual food removed by sanitation is necessary to prevent reinfestation. When sanitation is implemented only in areas with high trap catches to reduce cost, insects from other areas of the retail store may reinfest the area cleaned. In retail stores, inspection of packaged commodities for insect infestation and disposal of infested commodities may be necessary to prevent reinfestation. Structural modifications of equipment and facilities may be needed to make sanitation cost effective. Sanitation is not a one time cleaning but requires repeated cleanings.

References

Apt, A. C. 1955. A Study in the role of vacuum cleaning in the control of insects in flour mills. Milling Production 20(8): 5–7. Vacuum cleaning alone may reduce insect population for several months when impractical to close down for spot fumigation.

Brijwani, Monika, Bhadriraju Subramanyam, and Paul W. Flinn. 2012. Impact of Varying Levels of Sanitation on Mortality of Tribolium castaneum Eggs and Adults During Heat Treatment of a Pilot Flour Mill. Journal of Economic Entomology 105(2): 703–708. Egg mortality decreased linearly with an increase in flour depth, whereas that of adults decreased exponentially.

Herron, G. A., A. D. Clift, G. G. White, and H. G. Greening. 1996. Relationships between Insecticide Use, Grain Hygiene and Insecticide Resistance in Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on Grain-Producing Farms. Journal of Stored Products Research 32(2): 131–136. Hygiene measures by themselves had little effect on infestation levels, but good hygiene improved the efficacy of protectant treatment.

Ingemansen, J. A., Reeves, D. L., and Walstrom, R. J. 1986. Factors influencing stored-oat insect populations in South Dakota. J. Econ. Entomol. 79:518-522. Bins cleaned with a vacuum cleaner before filling had significantly lower average insect density levels than those cleaned with a scoop shovel or broom.

Jacobson, R., and D. B. Pinniger 1982. Eradication of Oryzaephilus surinamenisis from a Farm Grain Store. International Pest Control 24(3): 68–74. Pressure cleaning made a significant contribution to the effectiveness of the subsequent residual insecticide treatment.

Makinya, Kobia Jesee, John M. Wagacha, Judith A. Odhiambo, Paddy Likhayo, …, and Christopher M. Mutungi 2021. The Importance of Store Hygiene for Reducing Post-Harvest Losses in Smallholder Farmers’ Stores: Evidence from a Maize-Based Farming System in Kenya. J. Stored Prod. Res. 90, 101757. Nine out of ten farmers cleaned their stores before introducing the new harvest, but only half cleaned their stores during the course of storage.  Sweeping was the preferred method of cleaning and  almost 20% of farmers, in addition to sweeping, mopped, or dusted the stores. High hygiene scores correlated significantly with lower losses. Co-storage with stover or animal feed (29%), old storage containers (41%), farm implements (30%) and other crops (65%) was common and increased losses by 2.8 percentage points. Recycling of old storage bags (40%) was common and close to half (46%) disinfested by treating with chemicals (53.2%), exposing in the sun (17.7%), or dipping in hot (19.4%) or cold (9.7%) water.

Mason, L., W. Tsai, and K. Ileleji 2010. Influence of sanitation on post-fumigation pest rebound. p. 983. In Proceedings of the 10th International Working Conference on Stored Product Protection, Estoril, Portugal, 27 June–2 July 2010; Carvalho, M.O., Fields, P.G., Adler, C.S., Arthur, F.H., Athanassiou, C.G., Campbell, J.F., Fleurat-Lessard, F., Flinn, P.W., Hodges, R.J., Isikber, A.A., et al., Eds. Highest sanitation levels achieved the longest rebound time and thus received the maximum fumigation benefit. Those facilities that had poor sanitation practices, rebounded very quickly, sometimes within months, to pre-fumigation levels.

McKirdy, Simon J., Simon O’Connor, Melissa L. Thomas, Kristin L. Horton, Angus Williams, Darryl Hardie, Grey T. Coupland, and Johann van der Merwe. 2019. Biosecurity risks posed by a large sea-going passenger vessel: challenges of terrestrial arthropod species detection and eradication. Scientific reports 9(1): 1-14. Tribolium destructor was detected via visual inspection but not by trapping on 3 decks where food was processed and consumed. Numbers of adults and larvae were reduced but T. destructor was not fully eradicated by cleaning and insecticide spray.

Morrison, William, Alexander Bruce, Rachel Wilkins, Chloe Albin, and Frank Arthur. 2019. Sanitation Improves Stored Product Insect Pest Management. Insects 10(3), 77.  Decreased sanitation negatively affected the efficacy of most other pest management practices with a mean 1.3 to 17-fold decrease in efficacy.

Nakamura, Satoshi, Porntip Visarathanonth, Rungsima Kengkarnpanich, Jaitip Uraichuen, and Kazuhiko Konishi 2008. Cleaning Reduces Grain Losses of Stored Rice. Japan Agricultural Research Quarterly (JARQ) 42(1): 35–40. In one room, the floor, ceiling, walls and the surface of the rice bags were cleaned by sweeping with a broom to remove residues, dust and spider webs just after the rice bags were brought in the room at the beginning of the experiment and once a month after sampling (see below), while in the other room no cleaning was done. Cleaning of the storage premises decreased grain losses on all the types of rice.

Nansen, C., B. Subramanyam, and R. Roesli. 2004. Characterizing Spatial Distribution of Trap Captures of Beetles in Retail Pet Stores Using SADIE (R) Software. Journal of Stored Products Research 40 (5): 471–83. Sanitation was conducted in areas under the shelves where birdseed, dry dog food, dry cat food, and bulk-stored pet foods were displayed and trap captures were consistently high. Sanitation included sweeping and vacuuming of spillage under kick plates, dust and dirt on floors, and cleaning of shelves with wild birdseed and small pet animal food products. Sanitation also included discarding the bulk-stored food products because they were infested. A total of 21 person hours was spent performing sanitation in each store. According to store managers the sanitation we performed was considerably more thorough than their routine daily sanitation. The weevils, Sitophilus spp., drug store beetle, Stegobium paniceum (L.), and red flour beetle, Tribolium castaneum (Herbst) in two retail pet stores in Kansas, USA, were sampled with pitfall traps on five separate occasions before and four separate occasions after a thorough sanitation in areas with high trap captures. Captures of Sitophilus spp. in store 1 and T. castaneum in store 2 increased immediately after sanitation, but subsequently were similar to levels before sanitation, whereas captures of S. paniceum in store 1 and Sitophilus spp. in store 2 were unaffected by sanitation.

Rolston, L.H. and P. Rouse 1957.Insects in stored rice can be controlled by sanitation. Arkansas Farm Research July-August p. 3. Sanitation of empty bins followed by insecticide spray effective in 18 of 21 bins of stored rice.

Reed, C. R., Hagstrum, D. W. and Flinn, P. W. 2003. Wheat in bins and discharge spouts, and grain residues on floors of empty bins in concrete grain elevators as habitats for stored-grain beetles and their natural enemies. Journal of Economic Entomology 96(3): 996–1004. Cleaning the empty bins before refilling with newly-harvested wheat resulted in a significantly-reduced density of pest insects in discharge spouts later, and the effect lasted at least 12 weeks after filling.

Reed, C., and J. Harner. 1998. Thermostatically Controlled Aeration for Insect Control in Stored Hard Red Winter Wheat. Applied Engineering in Agriculture 14: 501–505. Grain cooling early in the storage season resulted in the insect populations being controlled when adequate sanitation was practiced. After this study was complete and the grain had been moved, the bins were cleaned thoroughly before cold winter weather arrived. Three weeks before the harvest, bins were recleaned and the bin bottoms were fumigated. After the bins were filled with newly harvested wheat, all grain was cooled immediately by controlled aeration. Immediately after harvest, the mean number of insects per trap was reduced to 1.3 (compared to 21 the previous year).

Williams, Scott B., Corinne E. Alexander, and Linda J. Mason. 2015. Sanitation’s Impact on the Effectiveness of the Pest Management Programs of Food Processing Facilities. Journal of Stored Products Research 60: 48–53. Sanitation, a preventative measure, may improve the effectiveness and reliability of other control methods, which may also reduce the cost of pest management for food processors when using these methods. Bioassay results suggested an equal level of effectiveness of fumigation for both facilities, but monitoring data suggested that the cleaner facility (Facility A) had slower pest population rebound rates than the less-clean facility (Facility B). Comparison of pest control costs in each facility revealed that Facility A spent less than Facility B on pest control as predicted, but also spent less on sanitation. These findings appear to correlate with the early results of an online survey that seeks a broader perspective of industry trends.

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