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PubMed1973

Evaluation of the salmonellae fluoro-kit for fluorescent-antibody staining.

An evaluation of the newly developed Clinical Sciences, Inc. Salmonellae Fluoro-Kit, which attempts to standardize the various aspects of the fluorescent-antibody (FA) procedure, was performed with 120 naturally contaminated human food, animal feed, and raw material samples. The Association of Official Analytical Chemists (AOAC) method for the detection of salmonellae was used as the control method. The Fluoro-Kit was found to be simple and conveniento to use. The results of this preliminary study show an industrially acceptable rate of recovery of salmonellae by using the Fluoro-Kit in comparison with the A.O.A.C. method. The Fluoro-Kit shows promise as a rapid, salmonellae FA screening method. Problems originally encountered in the application of the Fluoro-Kit are discussed. According to the manufacturer, strict adherence to the now revised procedures included in the Fluoro-Kit will control these problems.

Animal Feed↗
PubMed2002

[Hygienic conditions of hot dogs sold on the streets, Brazil].

The study objective was to identify the circumstances where there was risk of contamination of food (hot dogs) prepared and sold on the streets and to establish a preventive action through the creation of key surveillance sites. Data were collected from 20 vending sites using interviews, questionnaires, observations of food handling and storage, and temperature and pH measurements of both meat and sauce, respectively. In 30% of the studied sites, hygienic conditions were rated as regular to extremely poor. Mashed potatoes, chicken and beef preparations were of high risk. These findings showed inappropriate hygienic practices of food preparation and lack of basic knowledge regarding food handling - a public health problem. Given the scarcity of literature and official data on food sold in the streets of Brazil, further studies are recommended.

Brazil↗
PubMed2000

Norwalk-like virus sequences detected by reverse transcription-polymerase chain reaction in mineral waters imported into or bottled in Switzerland.

Norwalk-like viruses (NLVs) is a genus belonging to the Caliciviridae. NLVs are transmitted by the fecal-oral and the aerosol route and are the most common cause of outbreaks of nonbacterial gastroenteritis. NLVs are responsible for an estimated 67% of all illnesses caused by known foodborne pathogens and for 96% of nonbacterial gastroenteritis in the United States. Many outbreaks could be associated with the consumption of primarily or secondarily contaminated foods. To our knowledge, no epidemic arising from contaminated mineral water has been reported. We investigated the presence of NLV sequences in 63 mineral waters of 29 different brands that were imported into or bottled in Switzerland. NLV sequences were detected in 21 mineral waters by reverse transcription-seminested polymerase chain reaction. Specimens of two NLV genogroups (gg), gg I and gg II, were randomly present in the contaminated samples. The presence of NLV sequences could not be correlated either with bottle characteristics or with chemical properties like mineralization, pH, or the presence of carbonic acid. Nucleotide sequence analysis of 12 NLV-positive samples revealed several point mutations. All isolated NLV gg I strains have a similarity of 70 to 87% with the common Desert Shield virus (UO4469), and all isolated NLV gg II strains have a similarity of 89 to 93% with the Camberwell virus (U46500). Possible reasons for the presence of NLV sequences in mineral waters are discussed.

DNA, Viral↗
PubMed2000

Microbial contamination of carcasses and equipment from an Iberian pig slaughterhouse.

The microbial contamination of carcasses and equipment has been studied in an industrial slaughterhouse of Iberian pigs. Samples of the surface of carcasses were taken at different stages of the process and aerobic plate count at 37 degrees C (APC), Enterobacteriaceae-count (E-count) and Escherichia coli-count (EC-count) were determined. It was demonstrated that in scalding and singeing the APC decreased (P < 0.01), while in the dehairing it increased (P < 0.01). The E-count and EC-count decreased in the scalding but increased in the evisceration (P < 0.001). The implementation of good manufacturing practices (GMP) in the stages of closure of the anus and evisceration significantly decreased the EC-count. It changed from 61.1% in carcasses without GMP that had counts higher than 1 log CFU/cm2 to only 7.4% in GMP carcasses. A final wash of the carcasses with potable water at high pressure (the only decontaminating treatment permitted in the European Union) was tested and failed to decrease the counts. It was also demonstrated that cleaning and disinfection of the dehairing and scraping machines is not effective.

Abattoirs↗
PubMed2002

Assessment and development of procedures and apparatus to reduce contamination of lamb carcasses during pelt removal in low-throughput abattoirs.

Two series of experiments were carried out to investigate methods of reducing contamination of lamb carcasses in low-throughput abattoirs, where cradle dressing is normally employed. In the first series, cradle design and pelt removal procedure were investigated, and a method was developed for assessing gross visible contamination. Significant improvements in microbiological and gross visible contamination (P < 0.01) were achieved by procedural changes only; modifications to the cradle design had no effect. In the second series of experiments, two improved methods of pelt removal and the effect of hand washing prior to carcass contact during the pelt removal procedure were investigated. The improved methods comprised a Frame system, in which the pelt was removed in a manner similar to that in a high-throughput inverted line, and a Hybrid system, in which the pelt was removed from the forequarters on a conventional cradle before the carcass was suspended in an "inverted" vertical position for removal of the pelt from the abdomen and hindquarters. The results of microbiological and gross visible contamination from these methods, with and without hand washing, were compared with the conventional Cradle method of pelt removal. Both the Hybrid and Frame systems had significantly less microbiological and gross visible contamination (P < 0.01). However, hand washing had no significant effect on the level of carcass contamination for all three methods of pelt removal. Greatest reductions in microbiological and gross visible contamination were achieved using techniques that minimized hand contact with the carcass during pelt removal by adoption of inverted dressing procedures. Equipment redesign did not reduce carcass contamination.

Abattoirs↗
PubMed2002

Molecular characterization of Listeria monocytogenes isolated from a poultry further processing facility and from fully cooked product.

This study was undertaken to explore environmental sources of Listeria monocytogenes in a commercial chicken further processing facility and to compare the isolates obtained from this facility with others obtained from fully cooked product. In a survey conducted at the processing facility, 40 environmental sites (encompassing two production lines and representing areas in which raw and cooked products are processed) were cultured for L. monocytogenes. The resulting isolates were subjected to molecular subtyping by ribotyping, and these isolates were compared with 25 isolates collected by plant personnel from product contact surfaces and from fully cooked product. Eighty-nine environmental and product isolates were divided into 15 distinct ribogroups. Two ribogroups included isolates from fully cooked product; the members of these two ribogroups were subjected to further analysis by pulsed-field gel electrophoresis, resulting in four clusters. L. monocytogenes isolates from fully cooked product produced on line 1 were found to be indistinguishable from isolates collected from (i) drains on the raw-product side of line 1 and (ii) the floor surface in the cooked-product area of line 1. L. monocytogenes isolates from fully cooked product from line 2 were found to be indistinguishable from isolates collected from (i) the spiral freezer exit conveyor on line 2, (ii) raw product contact surfaces on line 1, and (iii) drains in the cooked-product area of line 1. These data suggest that L. monocytogenes can colonize a poultry further processing facility and eventually be transferred to fully cooked product.

Animals↗
PubMed2002

Salmonella spp. on chicken carcasses in processing plants in Poland.

Chickens at selected points in the slaughter process and after slaughter on the dressing line in poultry plants were sampled and analyzed for Salmonella. These chickens came from the northeast part of Poland. The examinations were carried out in quarters I, II, III, and IV of 1999. All the birds were determined to be healthy by a veterinary inspection. Swab samples were taken from the cloaca after stunning and from the skin surface and body cavity of the whole bird after evisceration, after rinsing at the final rinse station but before chilling in the spin-chiller, and after cooling in the continuous cooling plant at the end of the production day. In 1999, 400 whole chickens were examined. The percentage of these 400 chickens from which Salmonella spp. were isolated was relatively high (23.75%; Salmonella-positive results were observed in 95 cases). Salmonella spp. were found after stunning in 6% of the chickens (6 of 100 samples), after evisceration in 24% (24 of 100), before cooling in 52% (52 of 100), and after cooling in 13% (13 of 100). These results show that Salmonella spp. were found more often at some processing points than at others. The lowest Salmonella spp. contamination rate (6%) for slaughter birds was found after stunning, and the highest contamination rate was found before chilling (52%). The serological types of Salmonella spp. isolated from whole chickens were Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Saintpaul, Salmonella Agona, and Salmonella Infantis. The results of these investigations indicate that Salmonella Enteritidis is the dominant serological type in infections of slaughter chickens, as it is in many countries.

Animals↗
PubMed2003

Persistent and nonpersistent Listeria monocytogenes contamination in meat and poultry processing plants.

Contamination analysis of persistent and nonpersistent Listeria monocytogenes strains in three meat processing plants and one poultry processing plant were performed in order to identify factors predisposing to or sustaining persistent plant contamination. A total of 596 L. monocytogenes isolates were divided into 47 pulsed-field gel electrophoresis (PFGE) types by combining the restriction enzyme patterns of AscI (42 patterns) and ApaI (38 patterns). Persistent and nonpersistent strains were found in all plants. Nonpersistent PFGE types were found mostly at one sampling site, with the processing environment being the most common location, whereas the persistent strains were found at several sampling sites in most cases. The processing machines were frequently contaminated with persistent L. monocytogenes PFGE types, and it was of concern that surfaces having direct contact with the products were contaminated. The role of the processing machines in sustaining contamination and in contaminating the products appeared to be important because the final product of several processing lines was contaminated with the same L. monocytogenes PFGE type as that found in the processing machine. The proportion of persistent PFGE types in heat-treated products was eight times higher than in the raw products, showing the importance of the persistent PFGE types as contaminants of the final heat-treated products. The contamination status of the processing lines and machines appeared to be influenced by the compartmentalization of the processing line, with poor compartmentalization increasing L. monocytogenes contamination. The separation of raw and post-heat treatment areas seemed especially important in the contamination status of post-heat treatment lines.

Animals↗
PubMed2003

Molecular characterization of Arcobacter isolates collected in a poultry slaughterhouse.

In a poultry slaughterhouse, Arcobacter contamination was examined over a period of 1 week to establish possible routes of contamination. Samples were collected from the slaughter equipment and from processing water before the onset of slaughter and from the first broiler flock slaughtered on each sampling day. Characterization of 1,079 isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction and a random amplified polymorphic DNA assay resulted in the delineation of 159 Arcobacter butzleri and 139 Arcobacter cryaerophilus types. From almost all 140 neck skin samples collected before and after evisceration, A. butzleri and A. cryaerophilus were isolated simultaneously at contamination levels ranging from 10(1) to 10(4) CFU/g. Only six A. butzleri types present in the slaughterhouse environment were also present on the broiler carcasses. None of the A. cryaerophilus genotypes were detected in both the neck skin and the environmental samples. All A. butzleri types isolated from the feather samples were also isolated from broiler neck skin samples. The slaughter equipment was contaminated with arcobacters before the onset of slaughter, but it appeared unlikely that contamination through the slaughter equipment alone explained the high contamination levels on poultry products. Arcobacters were also present in processing water, but types present in water and poultry products were different. Characterization of the Arcobacter isolates did not clarify the routes of transmission, probably because of the extreme heterogeneity among Arcobacter isolates. However, the results obtained in this study brought to light insufficient decontamination at the processing plant involved in the study and confirmed the survival capacity of certain A. butzleri strains.

Abattoirs↗
PubMed2003

Class 1 and class 2 integrons in poultry carcasses from broiler house and poultry processing environments.

Integrons have been identified as major genetic contributors to the dissemination of antimicrobial resistance in bacteria. The objective of this study was to examine the prevalence of integrons in poultry processing at the broiler house and in processing plants. Class 1 and class 2 integrons were found throughout the processing environment. Of the two classes of integrons, class 1 was the most prevalent in all processing areas. The levels of both classes of integrons decreased from the farm to the processing plant. Within the chiller tank in the processing plant, the persistence of these sequences appears to be related to the free chlorine concentration of the chiller tank water. The variable regions of the amplified integrons showed size diversity (from 680 to 2,000 bp), suggesting diversity in types of antibiotic-resistance-coding gene cassettes. The presence of the class 1 and class 2 integrons in the chlorinated chiller tank suggests that these sequences are capable of withstanding this critical step in the reduction of microbial loads on poultry carcasses. The persistence of the integron gene sequences on the farm and throughout processing highlights the stability of these transmissible antibiotic-resistance-coding nucleotide sequences and their potential role as reservoirs of antibiotic-resistance-coding genetic elements within the poultry rearing and processing environments.

Animals↗
PubMed2004

Use of MIDI-fatty acid methyl ester analysis to monitor the transmission of Campylobacter during commercial poultry processing.

The presence of Campylobacter spp. on broiler carcasses and in scald water taken from a commercial poultry processing facility was monitored on a monthly basis from January through June. Campylobacter agar, Blaser, was used to enumerate Campylobacter in water samples from a multiple-tank scalder; on prescalded, picked, eviscerated, and chilled carcasses; and on processed carcasses stored at 4 degrees C for 7 or 14 days. The MIDI Sherlock microbial identification system was used to identify Campylobacter-like isolates based on the fatty acid methyl ester profile of the bacteria. The dendrogram program of the Sherlock microbial identification system was used to compare the fatty acid methyl ester profiles of the bacteria and determine the degree of relatedness between the isolates. Findings indicated that no Campylobacter were recovered from carcasses or scald tank water samples collected in January or February, but the pathogen was recovered from samples collected in March, April, May, and June. Processing generally produced a significant (P < 0.05) decrease in the number of Campylobacter recovered from broiler carcasses, and the number of Campylobacter recovered from refrigerated carcasses generally decreased during storage. Significantly (P < 0.05) fewer Campylobacter were recovered from the final tank of the multiple-tank scald system than from the first tank. MIDI similarity index values ranged from 0.104 to 0.928 based on MIDI-fatty acid methyl ester analysis of Campylobacterjejuni and Campylobacter coli isolates. Dendrograms of the fatty acid methyl ester profile of the isolates indicated that poultry flocks may introduce several strains of C. jejuni and C. coli into processing plants. Different populations of the pathogen may be carried into the processing plant by successive broiler flocks, and the same Campylobacter strain may be recovered from different poultry processing operations. However, Campylobacter apparently is unable to colonize equipment in the processing facility and contaminate broilers from flocks processed at later dates in the facility.

Animals↗
PubMed2004

Transfer of spinal cord material to subsequent bovine carcasses at splitting.

During the slaughter process, cattle carcasses are split by sawing centrally down the vertebral column, resulting in contamination of each half with spinal cord material. Using a novel method based on a real-time PCR assay, we measured saw-mediated tissue transfer among carcasses. Up to 2.5% of the tissue recovered from each of the five subsequent carcasses by swabbing the split vertebral face came from the first carcass to be split; approximately 9 mg was spinal cord tissue. Under controlled conditions in an experimental abattoir, between 23 and 135 g of tissue accumulated in the saw after splitting five to eight carcasses. Of the total tissue recovered, between 10 and 15% originated from the first carcass, and between 7 and 61 mg was spinal cord tissue from the first carcass. At commercial plants in the United Kingdom, between 6 and 101 g of tissue was recovered from the saw, depending on the particular saw-washing procedure and number of carcasses processed. Therefore, if a carcass infected with bovine spongiform encephalopathy were to enter the slaughter line, the main risk of subsequent carcass contamination would come from the tissue debris that accumulates in the splitting saw. This work highlights the importance of effective saw cleaning and indicates that design modifications are required to minimize the accumulation of spinal cord tissue debris and, hence, the risk of cross-contamination of carcasses.

Abattoirs↗
PubMed2005

Factors affecting the microbiological condition of the deep tissues of mechanically tenderized beef.

Whole or halved top butt prime beef cuts were treated in two types of mechanical tenderizing machines that both pierced the meat with thin blades but that used blades of different forms. Aerobes on meat surfaces and in the deep tissues of cuts after treatments were counted. When cuts were treated at a laboratory using a Lumar machine, the contamination of deep tissues increased significantly (P < 0.01) with increasing numbers of aerobic bacteria on meat surfaces and decreased significantly (P < 0.001) with increasing distance from the incised surface. However, contamination did not increase significantly (P > 0.1) with repeated incising of the meat. When halved cuts were incised one or eight times using a commercially cleaned Ross machine at a retail store, the numbers of aerobes recovered from deep tissues were similar with both treatments. When halved cuts were treated in one or other machine, deep tissue contamination was greater with the Lumar machine than with the Ross machine. Contamination of deep tissues as a result of tenderizing by piercing with thin blades can be minimized if the blades are designed to limit the number of bacteria carried into the meat and the microbiological condition of incised surface is well controlled.

Animals↗
PubMed2005

Distribution of Listeria monocytogenes subtypes within a poultry further processing plant.

Samples from environmental sites and raw product in a chicken further processing plant were collected every 6 weeks for 12 months. Each sample site was examined before and after a complete production shift. All samples were examined for the presence of Listeria monocytogenes, which was detected in floor drains on the raw product side of the plant preoperation and in drains on both raw and cooked sides following 8 h of processing operation. L. monocytogenes also was detected in raw product and once in fully cooked product but never on cooked product contact surfaces. One hundred sixty-one isolates were collected from 75 positive samples. All isolates were subtyped using a sequence-based method, and 14 unique subtypes were detected through the course of the study. Four of these types were found repeatedly and appeared to be resident in the plant. Three of the four resident strains were detected on raw product at some point during the year-long study, suggesting that raw product may be one source of L. monocytogenes in the processing plant environment. These data highlight the need for research to investigate why some types of L. monocytogenes persist in a processing plant environment but others do not.

Animals↗
PubMed2006

Survival, elongation, and elevated tolerance of Salmonella enterica serovar Enteritidis at reduced water activity.

Growing microorganisms on dry surfaces, which results in exposure to low water activity (a(w)), may change their normal morphology and physiological activity. In this study, the morphological changes and cell viability of Salmonella enterica serovar Enteritidis challenged to low a(w) were analyzed. The results indicated that exposure to reduced a(w) induced filamentation of the cells. The amount of filamentous cells at a(w) 0.94 was up to 90% of the total number of cells. Surviving filamentous cells maintained their membrane integrity after exposure to low a(w) for 21 days. Furthermore, cells prechallenged to low a(w), obtained with an ionic humectant, demonstrated higher resistance to sodium hypochlorite than control cells. These resistant cells are able to survive disinfection more efficiently and can therefore cause contamination of foods coming in contact with surfaces. This points to the need for increased attention to cleaning of surfaces in household environments and disinfection procedures in processing plants.

Colony Count, Microbial↗
PubMed2006

Transfer of Listeria monocytogenes during slicing of turkey breast, bologna, and salami with simulated kitchen knives.

In response to continued concerns regarding Listeria cross-contamination during the slicing of deli meats, a series of specially prepared grade 304 and 316 stainless steel kitchen knife blades was inoculated with a six-strain Listeria monocytogenes cocktail (10(8), 10(5), and 10(3) CFU per blade) composed of two weak, two medium, and two strong biofilm-forming strains. The blades were then attached to an Instron 5565 electromechanical compression analyzer and used to slice whole chubs of delicatessen turkey breast, bologna, and salami to entirety (30 slices) at a cutting speed of 8.3 mm/s. Homogenates of the slices in University of Vermont Medium were surface or pour plated with modified Oxford agar and then enriched. Listeria transfer from knife blades inoculated at 10(8) CFU per blade was logarithmic, with a 2-log decrease seen after 8 to 12 slices and direct counts obtained thereafter out to 30 slices. However, blades containing 10(5) and 10(3) CFU per blade typically yielded direct counts out to only 20 and 5 slices, respectively. Normalizing data on a log scale for the first 10 slices resulted in significantly greater Listeria transfer and "tailing" from grade 304 as opposed to grade 316 stainless (P < 0.05) for all three products. After 1 year of use, surface roughness values as determined by surface profilometry were significantly greater (P < 0.001) for grade 304 than for grade 316 stainless blades. Cutting force and blade sharpness were not significantly different (P > 0.05) within stainless steel grade (P < 0.05) for each product. However, significant differences in cutting force were seen between salami and turkey (P < 0.05) for grades 304 and 316 stainless, respectively. In addition to compositional differences in the deli meats and knife blades, wear and scoring on the blade likely affected Listeria transfer during slicing.

Animals↗
PubMed2006

Transfer of Listeria monocytogenes during mechanical slicing of turkey breast, bologna, and salami.

A commercial delicatessen slicer was used as the vector for sequential quantitative transfer of Listeria monocytogenes (i) from an inoculated slicer blade (approximately 10(8), 10(5), or 10(3) CFU per blade) to 30 slices of uninoculated delicatessen turkey, bologna, and salami, (ii) from inoculated product (approximately 10(8) CFU/cm2) to the slicer, and (iii) from inoculated product (10(8), 10(5), or 10(3) CFU/cm2) to 30 slices of uninoculated product via the slicer blade. Cutting force and product composition also were assessed for their impact on L. monocytogenes transfer. Five product contact areas on the slicer, which were identified from residue of product bathed in Glow-Germ, were also sampled using a 1-ply composite tissue technique after inoculated product had been sliced. After being sliced with inoculated blades, each product slice was surface or pour plated on modified Oxford agar and/ or enriched in University of Vermont medium. Greater transfer (P < 0.05) occurred from inoculated turkey (10(8) CFU/cm2) to the five slicer contact areas from an application force of 4.5 kg as compared with 0 kg. On uninoculated product sliced with blades inoculated at 10(8) CFU per blade, L. monocytogenes populations decreased logarithmically to 10(2) CFU per slice after 30 slices. Findings for the inoculated slicer blade and product (10(5) CFU per blade or cm2) were similar; L. monocytogenes concentrations were 102 CFU per slice after 5 slices and enriched samples were generally negative for L. monocytogenes after 27 slices. For uninoculated product sliced with blades inoculated at 10(3) CFU per blade, the first 5 slices typically produced L. monocytogenes at approximately 10 CFU per slice by direct plating, and enrichments were negative for L. monocytogenes after 15 slices. The higher fat and lower moisture content of salami compared with turkey and bologna resulted in a visible fat layer on the blade that likely prolonged L. monocytogenes transfer. As a result of cross-contamination, those delicatessen-sliced meats that allow growth of L. monocytogenes during prolonged refrigerated storage likely pose an increased public health risk for certain consumers.

Animals↗
PubMed2006

Contamination of cooked peeled shrimp (Pandalus borealis) by Listeria monocytogenes during processing at two processing plants.

Listeria spp. and Listeria monocytogenes contamination was evaluated in cooked peeled shrimp (final or semifinal product, 82 samples) and the shrimp-processing environment (two plants, 613 samples) in eight surveys conducted from 1998 through 2001. Listeria was detected in 12.5% (78) of the 695 samples (11.2% of the samples were positive for L. monocytogenes), but none of the samples of final product contained Listeria. One hundred seventy-two L. monocytogenes isolates were characterized by pulsed-field gel electrophoresis. Cleavage with macrorestriction enzymes AscI and ApaI yielded 14 different pulsotypes in the plants; two types were dominant, one in each plant. Sixty-three of the 106 isolates in plant A and 43 of the 66 isolates in plant B were of the dominant types. Certain strains, mainly of serotypes 1/2c and 4b and pulsotypes 1A and 2H, were persistent for long periods in both plants. Adaptation of good hygienic practices in the processing plants, including strict rules concerning traffic of staff and equipment, and existing hygienic requirements appeared to be effective in preventing contamination between areas within plants and in the final product. The persistence of Listeria strains in these two processing plants indicates the importance of detecting the places in the processing environment (e.g., transporters, equipment, floors, and drains) where L. monocytogenes can survive so that cleaning and disinfection efforts can be directed to such niches.

Animals↗