RKE Technical Bulletin – January 2022

Introduction to Bacillus cereus

Bacillus cereus is a toxin-producing anaerobic gram-positive bacterium. The bacteria are commonly found in the environment and can contaminate food. B. cereus can quickly multiply at room temperature with an abundantly present preformed toxin. This toxin can cause gastrointestinal illness when ingested, which is the commonly known manifestation of the disease. A variety of foods, particularly rice and leftovers, as well as sauces, soups, and other prepared foods that have sat out too long at room temperature are sources of B. cereus.

The duration of illness is typically around 24 hours with symptoms including vomiting, nausea and diarrhea, common “food poisoning” symptoms. Keeping foods out of the danger zone is important in prevention, especially if the if food is to be stored longer than two hours (keep hot foods hot (over 140°F) and cold foods cold (40°F or under). Cooked food should be stored in a wide, shallow container and refrigerate as soon as possible.

(More information available from the NCBI)

Submitted by: Rich Gibson ACE, CFSQA

The Yellow Meal Worm

Order: Coleoptera Family: Tenebrionidae Genus: Tenebrio

Mealworms are among some of the largest insect pests of stored products. The common name is derived from the color of the wireworm-like larvae. Yellow mealworms are in the genus Tenebrio, meaning “darkness,” owing to the nocturnal habits of the larvae. The adult is a polished dark brown or black beetle about one-half inch long. Its thorax is finely punctured, and its wing covers are longitudinally striated or grooved. There is only one generation each year.

Mealworms have generally been considered pests because their larvae feed on stored grains. Mealworms probably originated in the Mediterranean region but are now present in many areas of the world, spread by human trade and colonization.

Prevention is the best strategy to avoid insect problems in stored grains. Before grain is placed in a bin it should be screened to eliminate fine materials and broken kernels. Grain placed in a clean bin should be checked at two-week intervals during warm months and at one-month intervals during cooler months for the presence of hot spots, moldy areas, and live insects. If any of these conditions exist, the grain should be aerated to lower the moisture level and temperature. If infestation occurs in spite of these precautions, fumigation of the grain will be necessary.

Submitted by: Rich Gibson, ACE, CFSQA

Indian Meal Moths & Mating Disruption

Indian meal moths (IMM) are a very common household pest often found in homes, grocery stores and as we all know, food production and warehouse facilities. IMM go through complete metamorphosis which consists of egg, larva, pupae, and adult stages. The larvae are general feeders and can be found in grain products, seeds, dried fruit, dog foods and spices. Although very common, the Indian Meal Moth possesses several unusual traits that make it an infestation machine.

In the New England Region, there was a bakery that was brought on which was experiencing these “moths” flying around their whole operation. After an inspection was performed, it was clear the pest they were dealing with was an Indian Meal Moth. The previous pest control company did not appear to know much about this target pest, due to the lack of pheromone monitors in place, lack of documenting conditions that contribute to this pest thriving and no use of a chemical control.

Upon the set-up of the pest control program, hanging pheromone monitors were implemented and a deep dive inspection was performed. It was not before long that several “micro-environments” were found where very large populations of this target pest were festering. Some of these areas included: old bags of flour that were lost in storage, air ducts that have had large buildups of flour, industrial vacuums that have not been cleaned for long periods of time, flour build up on the indoor silo system, etc.

In environments where there are high levels of Indian Meal Moths, mating disruption is a great tool to help support the knockdown of the pest. Mating Disruption involves the use of sex pheromones to prevent male insects finding females and mating. The Mating Disruption program consists of hanging the strips in a grid pattern in areas that have moderate to high levels of activity. They are to be changed out every 5-6 months depending on the level of activity. The combination of deep dive inspections, improved sanitation, enhanced storage practices and mating disruption brought this client’s facility from 80 IMM’s captured in pheromone traps each week, down to an almost non-existent population.

• Take away Tips:
  1. Pheromone monitors allow for the identification of hot spots.
  2. Use science to control IMM development without the use of harmful pesticides
  3. Inspection always needs to be completed first to identify where to start
  4. Sanitation is an effective non-chemical control method

Submitted by: Tyler Connolly, Area Manager, RK Environmental Services