Prevalence of Campylobacteria in the Finnish Broiler Chicken Chain from the Producer to the Consumer

The prevalence of Campylobacter jejuni is 1.7 % (9/600) in the faeces of 4–5 week broiler chickens in Finland and 24 % (117/490) in the caeci of broiler chickens at slaughter. All waste waters at a processing plant, except water in a chlorinated (25 ppm) chilling tank, contained campylobacteria when a Campylobacter positive flock was slaughtered. Caeci contained mean logio 7.2 CFU campylobacteria/g. After chilling in a chlorinated ice–water tank there were still mean log10 4.5 CFU campylobacteria/carcass. Campylobacteria were detected from 7.0% (14/199) of deep–frozen broiler chicken carcasses at the market level. The concentration of C jejuni in naturally contaminated deep–frozen broiler chicken carcasses decreased by 2 log10 units in 4 weeks. All prevalence figures were lower than in other developed countries outside Scandinavia. In Finland one of the reasons for low prevalence may be the extensive use of Nurmi cultures in Salmonella prevention programs.     

Effect of various gas atmospheres on the growth and survival of Campylobacter jejuni on beef

Pieces of fresh beef were inoculated with three strains of Campylobacter jejuni. The meat was then allocated to three treatments: (a) vacuum packaged, (b) packaged in an atmosphere of 20% CO2 + 80% N2, and (c) packaged into sterile Petri dishes in anaerobic cultivation boxes, which were filled with a gas mixture of 5% O2 + 10% CO2 + 85% N2. The packaging material in the first two treatments was PA 80/PE 100-PE 100/PA 80/PE 100. The survival of Campylobacter cells was followed at 37 degrees C, 20 degrees C and 4 degrees C for 48 h, 4 days and 25 days, respectively. At 37 degrees C the counts of two Campylobacter strains increased in each package treatment for 48 h. At 20 degrees C and at 4 degrees C the counts of the same two strains decreased by 1 to 2 log units and 0.5 to 1 log unit, respectively, during storage. The survival of the two strains was about the same in all package treatments. The third strain was the most sensitive of the strains studied. At 37 degrees C its numbers increased only in the optimal gas atmosphere; at 20 degrees C the strain was not detectable after 24 to 48 h storage and at 4 degrees C after 4 days storage. The aerobic plate counts were determined for all samples at the same time as Campylobacter counts. The high indigenous bacterial numbers of the meat samples did not appear to have a great effect on the survival or growth of campylobacters.     

Effect of various gas atmospheres on the growth and survival of Campylobacter jejuni on beef

Pieces of fresh beef were inoculated with three strains of Campylobacter jejuni . The meat was then allocated to three treatments: (a) vacuum packaged, (b) packaged in an atmosphere of 20% CO₂+ 80% N₂, and (c) packaged into sterile Petri dishes in anaerobic cultivation boxes, which were filled with a gas mixture of 5% O₂+ 10% CO₂+ 85% N₂. The packaging material in the first two treatments was PA 80/PE 100–PE 100/PA 80/PE 100. The survival of Campylobacter cells was followed at 37°C, 20°C and 4°C for 48 h, 4 days and 25 days, respectively. At 37°C the counts of two Campylobacter strains increased in each package treatment for 48 h. At 20°C and at 4°C the counts of the same two strains decreased by 1 to 2 log units and 0.5 to 1 log unit, respectively, during storage. The survival of the two strains was about the same in all package treatments. The third strain was the most sensitive of the strains studied. At 37°C its numbers increased only in the optimal gas atmosphere; at 20°C the strain was not detectable after 24 to 48 h storage and at 4°C after 4 days storage. The aerobic plate counts were determined for all samples at the same time as Campylobacter counts. The high indigenous bacterial numbers of the meat samples did not appear to have a great effect on the survival or growth of campylobacters.     

Survival of cold-stressed Campylobacter jejuni on ground chicken and chicken skin during frozen storage

Campylobacter jejuni is prevalent in poultry, but the effect of combined refrigerated and frozen storage on its survival, conditions relevant to poultry processing and storage, has not been evaluated. Therefore, the effects of refrigeration at 4 degrees C, freezing at -20 degrees C, and a combination of refrigeration and freezing on the survival of C. jejuni in ground chicken and on chicken skin were examined. Samples were enumerated using tryptic soy agar containing sheep's blood and modified cefoperazone charcoal deoxycholate agar. Refrigerated storage alone for 3 to 7 days produced a reduction in cell counts of 0.34 to 0.81 log10 CFU/g in ground chicken and a reduction in cell counts of 0.31 to 0.63 log10 CFU/g on chicken skin. Declines were comparable for each sample type using either plating medium. Frozen storage, alone and with prerefrigeration, produced a reduction in cell counts of 0.56 to 1.57 log10 CFU/g in ground chicken and a reduction in cell counts of 1.38 to 3.39 log10 CFU/g on chicken skin over a 2-week period. The recovery of C. jejuni following freezing was similar on both plating media. The survival following frozen storage was greater in ground chicken than on chicken skin with or without prerefrigeration. Cell counts after freezing were lower on chicken skin samples that had been prerefrigerated for 7 days than in those that had been prerefrigerated for 0, 1, or 3 days. This was not observed for ground chicken samples, possibly due to their composition. C. jejuni survived storage at 4 and -20 degrees C with either sample type. This study indicates that, individually or in combination, refrigeration and freezing are not a substitute for safe handling and proper cooking of poultry.     

Survival of Campylobacter jejuni on beef trimmings during freezing and frozen storage

AIMS: To investigate the survival of two animal isolates of Campylobacter jejuni on beef trimmings during freezing and frozen storage. METHODS AND RESULTS: Meat packs inoculated with 10(3) or 10(6) cfu g(-1) of either strain of C. jejuni were frozen to -18 degrees C, and sampled at regular intervals over 112 d storage to determine Campylobacter numbers and sublethal injury. For both strains and inoculation levels the numbers of Campylobacter decreased in the first 7 d of storage by ca. 0.6-2.2 log cfu g(-1) and then remaining constant over the remainder of the storage trial, with neither isolate exhibiting sublethal injury. CONCLUSIONS: Despite an initially significant decrease in number, these pathogens were able to survive standard freezing conditions in meat, but did not exhibit sublethal injury. SIGNIFICANCE AND IMPACT OF THE STUDY: Strict hygiene and/or the implementation of decontamination technologies are recommended as a means to assure the safety of meat with respect to this pathogen.     

Correlation of Campylobacter bacteriophage with reduced presence of hosts in broiler chicken ceca

Campylobacter jejuni and Campylobacter-specific bacteriophage were enumerated from broiler chicken ceca selected from 90 United Kingdom flocks (n = 205). C. jejuni counts in the presence of bacteriophage (mean log(10) 5.1 CFU/g) were associated with a significant (P < 0.001) reduction compared to samples with Campylobacter alone (mean log(10) 6.9 CFU/g).     

Prevalence of <Emphasis Type="Italic">Campylobacter</Emphasis> spp. in poultry and poultry products for sale on the Bulgarian retail market

The aim of this study was to investigate the presence of Campylobacter spp. in poultry and poultry products available for the consumers at retail markets in Bulgaria. Samples (n = 210) of poultry carcasses and poultry products for sale at the retail market in Bulgaria were analysed for the presence of Campylobacter spp., of these 35 frozen whole carcasses, 135 chilled poultry cuts (45 wing cuts, 45 thigh cuts and 45 fillet) and 40 thermally treated (ready-to-eat) poultry products. The results obtained showed that 35.2% of the frozen poultry carcasses for sale in the markets were Campylobacter contaminated. In the chilled poultry cuts Campylobacter was isolated at the highest percentage in wing- and thigh cuts, 91.1% and 88.9%, respectively. The fillet samples were contaminated by Campylobacter in 48.9% of cases. In the chilled poultry products as well as in the frozen carcasses C. jejuni (74.8%/70.3%) was the most commonly isolated Campylobacter species, with the remainder being C. coli (25.2%/29.7%). Campylobacter spp. were not detected in the thermally treated poultry products.     

The Effect of Lactic Acid Sprays on Campylobacter jejuni Inoculated onto Poultry Carcasses

Spraying poultry carcasses with 1 % lactic acid 10 min after inoculation with Campylobacter jejuni, resulted in a significant reduction in the number of the bacteria after 4 h at 4°C. Some of the inoculated cells, however, survived for at least 144 h. Spraying 10 min after inoculation with 2% lactic acid, totally eliminated all inoculated C. jejuni within 24 h. On the other hand, spraying 24 h after inoculation, with either 1 % or 2 % lactic acid did not eliminate all the bacteria. Inoculated C. jejuni on poultry carcasses not sprayed with lactic acid, survived at 4°C throughout the sampling period (up to 144 h) and showed little tendency to decrease in number even when the carcasses started to deteriorate. Resident Campylobacters on poultry carcasses were significantly reduced by the lactic acid treatment. Frozen and thawed chickens appeared to show a graying of the skins immediately after spraying with lactic acid, slightly stronger with 2 % lactic acid, but the colour reverted to normal after 24 h. We were not able to observe any colour change on the fresh broiler chickens after lactic acid treatment. Our results indicated that lactic acid had a significant bactericidal effect on C. jejuni on both naturally and artificially contaminated poultry carcasses. This effect, however, became manifest only several hours after acid treatment.     

Survival of Campylobacter jejuni in chicken meat at frozen storage temperatures

The aim of this study was to determine the survival of Campylobacter jejuni in chicken meat samples at frozen temperatures and given length of incubation and to determine the impact of aerobic bacteria on the survival of C. jejuni. The chicken meat samples were inoculated with C. jejuni NCTC 11351 suspensions and stored in bags at temperatures of -20°C and -70°C. The mean value of C. jejuni from meat samples decreased from 7.52 log10 CFU/g after 30 minutes of incubation at ambient temperature, to 3.87 log10 CFU/g on the eighth week of incubation at -20°C, and to 3.78 log10 CFU/g at incubation at -70°C after the same incubation period. Both freezing temperatures, -20°C and -70°C, decreased the number of campylobacters. The presence of aerobic mesophilic bacteria did not influence the survival of C. jejuni in chicken meet samples. Keeping poultry meat at freezing temperatures is important for the reduction of C. jejuni, which has a strong influence on the prevention of occurrence of campylobacteriosis in humans.     

A Newer Method for Isolation of the 7S Globulin in Soybean Seeds

The effects of freezing on the proteolysis of beef during storage at 4°C after being thawed was investigated.

A sarcoplasmic 32-kDa protein in frozen as well as unfrozen beef decreased rapidly during storage at 4°C, and a more than 100-kDa protein appeared in both beef samples. And the increment of peptides in the frozen beef during the storage at 4°C was larger than that in the unfrozen beef, suggesting that the proteolysis was faster during the storage of the former than the latter. However, its increment in the frozen beef for 10 weeks during the storage at 4°C became smaller than that of the one frozen for less than 5 weeks.

To discover an indicator for evaluation of the conditioning of frozen and unfrozen beef, peptides produced during the storage of beef at 4°C were surveyed. A peptide, APPPPAEVPEVHEEV, was detected and seemed to be available as an indicator in the conditioning of beef.     

Fate of Escherichia coli O157:H7 in ground beef following high‐pressure processing and freezing

Aims: The purposes of this study were to evaluate the efficacy of high pressure to inactivate Escherichia coli O157:H7 in ground beef at ambient and subzero treatment temperatures and to study the fate of surviving bacteria postprocess and during frozen storage. Methods and Results: Fresh ground beef was inoculated with a five‐strain cocktail of E. coli O157:H7 vacuum‐packaged, pressure‐treated at 400 MPa for 10 min at ?5 or 20°C and stored at ?20 or 4°C for 5–30 days. A 3‐log CFU g^?1 reduction of E. coli O157:H7 in the initial inoculum of 1 × 10⁶ CFU g^?1 was observed immediately after pressure treatment at 20°C. During frozen storage, levels of E. coli O157:H7 declined to <1 × 10² CFU g^?1 after 5 days. The physiological status of the surviving E. coli was affected by high pressure, sensitizing the cells to pH levels 3 and 4, bile salts at 5% and 10% and mild cooking temperatures of 55–65°C. Conclusions: High‐pressure processing (HPP) reduced E. coli O157:H7 in ground beef by 3 log CFU g^?1 and caused substantial sublethal injury resulting in further log reductions of bacteria during frozen storage. Significance and Impact of the Study: HPP treatment of packaged ground beef has potential in the meat industry for postprocess control of pathogens such as E. coli O157:H7 with enhanced safety of the product.     

Survival of Cold-Stressed Campylobacter jejuni on Ground Chicken and Chicken Skin during Frozen Storage

Campylobacter jejuni is prevalent in poultry, but the effect of combined refrigerated and frozen storage on its survival, conditions relevant to poultry processing and storage, has not been evaluated. Therefore, the effects of refrigeration at 4°C, freezing at −20°C, and a combination of refrigeration and freezing on the survival of C. jejuni in ground chicken and on chicken skin were examined. Samples were enumerated using tryptic soy agar containing sheep's blood and modified cefoperazone charcoal deoxycholate agar. Refrigerated storage alone for 3 to 7 days produced a reduction in cell counts of 0.34 to 0.81 log₁₀ CFU/g in ground chicken and a reduction in cell counts of 0.31 to 0.63 log₁₀ CFU/g on chicken skin. Declines were comparable for each sample type using either plating medium. Frozen storage, alone and with prerefrigeration, produced a reduction in cell counts of 0.56 to 1.57 log₁₀ CFU/g in ground chicken and a reduction in cell counts of 1.38 to 3.39 log₁₀ CFU/g on chicken skin over a 2-week period. The recovery of C. jejuni following freezing was similar on both plating media. The survival following frozen storage was greater in ground chicken than on chicken skin with or without prerefrigeration. Cell counts after freezing were lower on chicken skin samples that had been prerefrigerated for 7 days than in those that had been prerefrigerated for 0, 1, or 3 days. This was not observed for ground chicken samples, possibly due to their composition. C. jejuni survived storage at 4 and −20°C with either sample type. This study indicates that, individually or in combination, refrigeration and freezing are not a substitute for safe handling and proper cooking of poultry.     

Detection of cytolethal distending toxin activity and cdt genes in Campylobacter spp. isolated from chicken carcasses

This study was designed to determine whether isolates from chicken carcasses, the primary source of Campylobacter jejuni and Campylobacter coli in human infections, commonly carry the cdt genes and also whether active cytolethal distending toxin (CDT) is produced by these isolates. Campylobacter spp. were isolated from all 91 fresh chicken carcasses purchased from local supermarkets. Campylobacter spp. were identified on the basis of both biochemical and PCR tests. Of the 105 isolates, 70 (67%) were identified as C. jejuni, and 35 (33%) were identified as C. coli. PCR tests amplified portions of the cdt genes from all 105 isolates. Restriction analysis of PCR products indicated that there appeared to be species-specific differences between the C. jejuni and C. coli cdt genes, but that the restriction patterns of the cdt genes within strains of the same species were almost invariant. Quantitation of active CDT levels produced by the isolates indicated that all C. jejuni strains except four (94%) had mean CDT titers greater than 100. Only one C. jejuni strain appeared to produce no active CDT. C. coli isolates produced little or no toxin. These results confirm the high rate of Campylobacter sp. contamination of fresh chicken carcasses and indicate that cdt genes may be universally present in C. jejuni and C. coli isolates from chicken carcasses.     

Campylobacter jejuni: incidence in processed broilers and biotype distribution in human and broiler isolates.

Campylobacter jejuni was isolated from 18 of 40 processed broiler carcasses and 134 of 327 cloacal swabs obtained at four processing plants in Sydney, Australia. Three of four flocks examined carried C. jejuni. Eighty-two percent of chicken and 98% of human isolates from the area were of identical biotypes.     

The Effect of Nacl on Campylobacter Jejuni/Coli

The growth of 2 strains of Campylobacter jejuni/coli was investigated in 0–2.0 % NaCl in Brucella broth at 35° G and 30° C. Both strains tolerated more NaCl in the growth medium at 35° C than at 30° C. 2 % NaCl was bacteriocidic at both temperatures. The strains also grew in the medium without added NaCl. At 35° C, low concentrations of NaCl stimulated the growth of strain 5616, but not the growth of strain B33. At 30° C, strain 5616 grew in NaCl concentrations up to 1.0 % and strain B33 in 0 % and at the control concentration (0.5 % NaCl). The survival of 22 C. jejuni/coli strains in 2.0 % NaCl at 4° C and 35° C was also investigated. Human strains showed significantly greater tolerance to 2.0 % NaCl at both temperatures than did the strains isolated from animals. These findings suggest that the salting of food can be effective in preventing the growth or survival of C. jejuni/coli.     

Bacteriophage therapy to reduce Campylobacter jejuni colonization of broiler chickens

Colonization of broiler chickens by the enteric pathogen Campylobacter jejuni is widespread and difficult to prevent. Bacteriophage therapy is one possible means by which this colonization could be controlled, thus limiting the entry of campylobacters into the human food chain. Prior to evaluating the efficacy of phage therapy, experimental models of Campylobacter colonization of broiler chickens were established by using low-passage C. jejuni isolates HPC5 and GIIC8 from United Kingdom broiler flocks. The screening of 53 lytic bacteriophage isolates against a panel of 50 Campylobacter isolates from broiler chickens and 80 strains isolated after human infection identified two phage candidates with broad host lysis. These phages, CP8 and CP34, were orally administered in antacid suspension, at different dosages, to 25-day-old broiler chickens experimentally colonized with the C. jejuni broiler isolates. Phage treatment of C. jejuni-colonized birds resulted in Campylobacter counts falling between 0.5 and 5 log10 CFU/g of cecal contents compared to untreated controls over a 5-day period postadministration. These reductions were dependent on the phage-Campylobacter combination, the dose of phage applied, and the time elapsed after administration. Campylobacters resistant to bacteriophage infection were recovered from phage-treated chickens at a frequency of <4%. These resistant types were compromised in their ability to colonize experimental chickens and rapidly reverted to a phage-sensitive phenotype in vivo. The selection of appropriate phage and their dose optimization are key elements for the success of phage therapy to reduce campylobacters in broiler chickens.     

Comparison of the survival of Campylobacter jejuni and Campylobacter coli in culturable form in surface water

Six Campylobacter jejuni and six Campylobacter coli strains were isolated from cows and pigs, and their survival in lake water was compared by viable counts. Campylobacter jejuni survived longer in culturable form than C. coli in untreated and membrane-filtered water both at 4 and 20 degrees C. This difference in survival time may be a reason why C. jejuni is generally isolated from surface waters more frequently than C. coli. Both species survived better in filtered than in untreated water. This suggests that predation and competition for nutrients affect the survival of both Campylobacter species in the aquatic environment.     

Cryopreservation studies of Campylobacter

Seven strains of Campylobacter fetus ss. fetus, one of Campylobacter fetus ss. venerealis, and one of Campylobacter jejuni were preserved using a variety of cryopreservation methods. Organisms were frozen to -150 degrees C in a liquid nitrogen refrigerator, in the freezer compartment of a refrigerator (-20 degrees C), and in a mechanical freezer (-65 degrees C). In the latter two cases, viabilities of the organisms were compared after being frozen in Brucella Albimi broth and 10% glycerol. Viabilities were also examined after Campylobacter species were freeze-dried using rapid or slow cooling, using sucrose or skim milk as cryoprotective agents and in bulb-type vials on a manifold or batch vials. Preservation in liquid nitrogen resulted in no loss in viability after 4 years storage. When Campylobacter species were frozen at -20 degrees C, no cells were recovered after 1 month storage in Brucella Albimi broth or seven months in glycerol. A 6.5 log decrease in viability resulted after organisms were frozen at -65 degrees and subsequently stored at the same temperature for 2 years. In this case, glycerol had no protective advantage over Brucella Albimi broth. Postpreservation viability of organisms cooled slowly was two logs higher than those cooled rapidly prior to freeze-drying. When skim milk or sucrose were employed as cryoprotective agents during freeze-drying, equal viabilities resulted. Equivalent viabilities were also demonstrated when the bulb type or "batch" vials were utilized for freeze-drying. No significant differences were observed between the viabilities of the three species when a given cryopreservation method was employed.     

Campylobacter jejuni survival in chicken meat as a function of temperature.

Recognition of Campylobacter fetus subsp. jejuni (referred to hereafter as C. jejuni) as an important human pathogen and its isolation from meat products indicate the need for knowledge of its survival characteristics in meats. Thermal death times (D-values) for a single strain and a five-strain composite were determined in 1% peptone and autoclaved ground chicken meat at temperatures ranging from 49 to 57 degrees C. Survival was determined for these strains in chicken meat at 4, 23, 37, and 43 degrees C. Survival was also determined on raw chicken drumsticks stored at 4 degrees C in either an ambient or a CO2 atmosphere. D-values were greater in chicken meat than in peptone in all cases. D-values in peptone for strain H-840 at 49, 51, 53, 55, and 57 degrees C were 15.2, 4.90, 1.71, 0,64, and 0.25 min, respectively. The corresponding D-values in ground chicken meat were 20.5, 8.77, 4.85, 2.12, and 0.79 min, respectively. Similar results were obtained with a composite of five strains. When sterile ground chicken meat was inoculated with approximately 10(6) to 10(7) C. jejuni cells per g and stored at 37 degrees C in an ambient atmosphere, a 1-to 2-log count increase occurred during the first 4 days, followed by a gradual decline of about 1 log during the remainder of the 17-day storage period. No growth was observed among similarly inoculated samples that were stored at 4, 23, and 43 degrees C but counts declined by about 1 to 2 logs at 4 degrees C (17 day), by 2.5 to 5 logs at 23 degrees C (17 days), and to undetectable levels at 43 degrees C (between 10 and 16 days). Survival on raw chicken drumsticks stored at 4 degrees C in CO2 and in an ambient atmosphere declined by about 1.5 and 2.0 logs, respectively, during 21 days of storage. The effect of temperature on the survival of C. jejuni in chicken meat was similar to that reported in other natural and laboratory milieus. Ordinary cooking procedures that destroy salmonellae would be expected to destroy C. jejuni.     

Inactivation of Escherichia coli O157:H7, salmonellae, and Campylobacter jejuni in raw ground beef by gamma irradiation.

Raw ground beef patties inoculated with stationary-phase cells of Escherichia coli O157:H7, salmonellae, or Campylobacter jejuni were subjected to gamma irradiation (60Co) treatment, with doses ranging from 0 to 2.52 kGy. The influence of two levels of fat (8 to 14% [low fat] and 27 to 28% [high fat]) and temperature (frozen [-17 to -15 degrees C] and refrigerated [3 to 5 degrees C]) on the inactivation of each pathogen by irradiation was investigated. In ascending order of irradiation resistance, the D10 values ranged from 0.175 to 0.235 kGy (C. jejuni), from 0.241 to 0.307 kGy (E. coli O157:H7), and from 0.618 to 0.800 kGy (salmonellae). Statistical analysis revealed that E. coli O157:H7 had a significantly (P < 0.05) higher D10 value when irradiated at -17 to -15 degrees C than when irradiated at 3 to 5 degrees C. Regardless of the temperature during irradiation, the level of fat did not have a significant effect on the D10 value. Salmonellae behaved like E. coli O157:H7 in low-fat beef, but temperature did not have a significant effect when the pathogen was irradiated in high-fat ground beef. Significantly higher D10 values were calculated for C. jejuni irradiated in frozen than in refrigerated low-fat beef. C. jejuni was more resistant to irradiation in low-fat beef than in high-fat beef when treatment was at -17 to -15 degrees C. Regardless of the fat level and temperature during inactivation, these pathogens were highly sensitive to gamma irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)