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По умолчанию Eco-Friendly Drain Care

In previous studies workers determined that two lactic acid bacterium isolates, Lactococcus lactis subsp. lactis C-1-92 and Enterococcus durans 152 (competitive-exclusion bacteria [CE]), which were originally obtained from biofilms in floor drains, are bactericidal to Listeria monocytogenes or inhibit the growth of L. monocytogenes both in vitro and in biofilms at 4 to 37°C. We evaluated the efficacy of these isolates for reducing Listeria spp. contamination of floor drains of a plant in which fresh poultry is processed. Baseline assays revealed that the mean numbers of Listeria sp. cells in floor drains sampled on six different dates (at approximately biweekly intervals) were 7.5 log10 CFU/100 cm2 for drain 8, 4.9 log10 CFU/100 cm2 for drain 3, 4.4 log10 CFU/100 cm2 for drain 2, 4.1 log10 CFU/100 cm2 for drain 4, 3.7 log10 CFU/100 cm2 for drain 1, and 3.6 log10 CFU/100 cm2 for drain 6. The drains were then treated with 107 CE/ml in an enzyme-foam-based cleaning agent four times in 1 week and twice a week for the following 3 weeks. In samples collected 1 week after CE treatments were applied Listeria sp. cells were not detectable (samples were negative as determined by selective enrichment culture) for drains 4 and 6 (reductions of 4.1 and 3.6 log10 CFU/100 cm2, respectively), and the mean numbers of Listeria sp. cells were 3.7 log10 CFU/100 cm2 for drain 8 (a reduction of 3.8 log10 CFU/100 cm2), <1.7 log10 CFU/100 cm2 for drain 1 (detectable only by selective enrichment culture; a reduction of 3.3 log10 CFU/100 cm2), and 2.6 log10 CFU/100 cm2 for drain 3 (a reduction of 2.3 log10 CFU/100 cm2). However, the aerobic plate counts for samples collected from floor drains before, during, and after CE treatment remained approximately the same. The results indicate that application of the two CE can greatly reduce the number of Listeria sp. cells in floor drains at 3 to 26°C in a facility in which fresh poultry is processed Drain cleaning Atlanta.

Controlling the widely distributed psychrotrophic organism Listeria monocytogenes in food processing facilities has been a formidable challenge for the entire food industry, from the smallest food processor to the largest. Besides this pathogen's widespread occurrence in nature, it is nonfastidious, grows at refrigeration temperatures, and can form or coexist in protective biofilms (1, 2, 7, 15, 16). Floor drains in food processing facilities are a particularly important niche for the persistence of listeriae and can be a point of contamination in the processing plant environment and possibly in food products.

Decontaminating floor drains of Listeria sp. is especially challenging because when entrapped in a biofilm, Listeria sp. is afforded unusual protection against disinfectants and treatments available to control pathogens on environmental surfaces (7, 9, 14, 17, 18). Once attached, the cells may produce multicellular biofilms that are resistant to disinfection and from which cells can become detached and contaminate food products. The establishment of biofilms by pathogenic bacteria in floor drains in food processing plants is believed to protect against effective cleaning regimens and to reduce or minimize the efficacy of bactericidal treatments. Studies have indicated that L. monocytogenes growing within mixed-microflora biofilms in food processing environments can be a major source of contamination (1, 9, 20).
Promising in vitro results have been obtained in previous studies with two competitive-exclusion bacteria (CE), Lactococcus lactis subsp. lactis C-1-92 and Enterococcus durans 152, for inhibition of the growth of L. monocytogenes in culture media and in biofilms at temperatures ranging from 4 to 37°C (22). The objective of this study was to evaluate the efficacy of these CE in controlling listerial growth and possibly eliminating the pathogen in floor drains at a wide range of temperatures in a facility in which fresh poultry is processed, including under refrigeration conditions.
The poultry processing plant had two processing lines; each line processed 140 birds per min, and the plant had the capacity to process 400,200 birds per day. Approximately 268,800 birds were processed during a normal day with two shifts.
Based on the direction of flow of the drains, the fluid flow rate, the fluid volume, the drain size, the temperatures of rooms, and the occurrence and persistence of Listeria sp., six floor drains for CE treatment and an untreated control were identified. Drains 1 and 2 were open trenches (height, 25 cm; width, 30 cm) and were comprised of concrete with fiberglass covers. These drains were located close to poultry meat cutting lines at mean temperatures of 16.8 and 11.5°C, respectively, and largely contained liquid drippings from meat, including meat that had fallen on the floor. Drains 1 and 2 were typically filled to 10 to 30% of capacity during operation. Drain 3 was an open trench (height, 25 cm; width, 30 cm) comprised of concrete with metal edging and a metal cover. This drain was located in the middle of a high-traffic area at a mean temperature of 15.1°C and was typically 20 to 40% full during operation. Drains 4 and 6 were open trenches (height, 20 cm; width, 30 cm) and were comprised of fiberglass. They were located near poultry meat packing areas at mean temperatures of 2.8 and 3.8°C, respectively, and were typically filled to 5 to 20% of capacity during operation. Drain 8 was an open trench (height, 150 cm; width, 90 cm) and was comprised of concrete with a fiberglass cover. This drain was near a liver and lung removal line at a mean temperature of 26.1°C and contained blood and meat debris. It was typically filled with liquid to 15 to 20% of capacity.
Using sterile gloves, an 18-oz. sterile “speci-sponge” (3.8 by 7.6 cm; Nasco Laboratory, Fort Atkinson, WI) was used to wipe an area that was ca. 10 by 10 cm at each sampling location. Five locations, including the inside (bottom) of the drain, the right side of the drain, the left side of the drain, the bottom side of the trench cover, and the floor within 30 cm of the drain, were sampled for each floor drain. Each sponge was placed in a Whirl-Pak bag and kept at 5°C for 2 to 14 h until the sample was assayed.
Enumeration of Listeria sp. and L. monocytogenes.
Ten milliliters of 0.1% peptone was added to each bag, and the sponge and peptone were blended with a stomacher blender (Seward Medical, London, United Kingdom) at 150 rpm for 1 min. The fluid was serially diluted (1:10) in 0.1% peptone (Becton Dickinson Microbiology Systems, Sparks, MD), and 0.1 ml from each dilution tube was plated in duplicate on the surface of modified Oxford medium (MOX) (Oxoid, Ogdensburg, NY) plates. When Listeria sp. was not detected by the direct plating method, the broth plus the sponge was selectively enriched in 225 ml Fraser broth (Becton Dickinson Microbiology Systems) for 24 h at 37°C. Then 1 ml of the broth was serially diluted (1:10) in 0.1% peptone to obtain 10−8 CFU/ml, and 0.1 ml of each dilution was surface plated on MOX plates in duplicate. The MOX plates were incubated at 37°C for 48 h, and typical black colonies were counted as presumptive Listeria sp. colonies. Colonies counted as Listeria sp. colonies were randomly selected and transferred to MOX plates, and they were confirmed to be Listeria sp. by biochemical tests (API 20I miniaturized diagnostic test; bioMérieux Vitek, Hazelwood, MO) and a lateral flow latex agglutination assay (Listeria Rapid Test; Oxoid, Ogdensburg, NY) and to be L. monocytogenes by an enzyme-linked fluorescent immunoassay with an automated VIDAS instrument (miniVIDAS; bioMérieux Vitek, Hazelwood, MO) and by a PCR assay (Qualicon BAX system; DuPont, Wilmington, DE).
Determination of aerobic plate counts (APCs).
Serial dilutions (duplicate 0.1-ml portions of each dilution) of the samples described above were surface plated on plate count agar plates (Becton Dickinson Microbiology Systems) and incubated at 30°C for 72 h for enumeration.
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