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This study was conducted to compare the efficacy of antimicrobials sprayed by electrostatic versus conventional sprayer for inactivation of Salmonella, Listeria monocytogenes, and Campylobacter jejuni on eggs and to determine the economic feasibility of these treatments. Eggs were dip inoculated with overnight cultures (18 h) of Salmonella Typhimurium, Salmonella Tennessee, a two-strain mixture of L. monocytogenes, and a three-strain mixture of C. jejuni (microaerophilic condition). Inoculated eggs were then not sprayed or subjected to electrostatic and conventional spraying with peroxyacetic acid (PAA; 0.1%), lactic acid (5.0%), lactic and citric acid blend (2.5%), sodium hypochlorite (SH; 50 ppm), and SaniDate-5.0 (SD [a mixture of PAA and H2O2]; 0.25%) for 30 s (15 s each side). Surviving bacteria on eggshells were recovered on xylose lysine Tergitol 4 agar ( Salmonella), modified Oxford agar ( L. monocytogenes), or Brucella agar ( C. jejuni). Compared with conventional spraying, electrostatic spraying of PAA, SD, and SH achieved significant additional reductions ( P < 0.05) of Salmonella, L. monocytogenes, and C. jejuni of 0.96 to 3.18, 1.19 to 3.05, and 0.96 to 1.62 log CFU per egg, respectively. A simple cost comparison suggests that regardless of the antimicrobial agent used, the cost of using an electrostatic sprayer is 20 to 40% lower than that of a conventional sprayer for a small poultry farm that produces 1,500 eggs per day. Among the five antimicrobials, the total sanitizing cost was lowest for SH, followed by PAA and SD. The results indicated that electrostatic spraying of commercial antimicrobials can be considered an effective and economical approach to enhancing the microbial safety of eggs, especially for small poultry processors.

Campylobacter jejuni , Campylobacter coli , and Campylobacter laridis are recognized causes of alimentary infections in humans. These infections are most often transmitted by foods of animal origin, with undercooked poultry or unpasteurized milk most frequently implicated as vehicles. There are no data on the prevalence and distribution of Campylobacter spp. on meats in Poland. We assessed 839 poultry, 105 porcine, and 114 bovine carcasses for the qualitative presence of the organism on the freshly processed product. The organisms were found on 80.3% of the chicken, 48.0% of the duck, 38.0% of the goose, and 3.0% of the turkey carcasses examined. The contamination on porcine and bovine carcasses was 2.9 and 0.9%, respectively. In addition, we assessed and determined that modified Campylobacter charcoal differential agar (CCDA) medium was more sensitive and selective than Campylobacter brucella agar plate (Campy-BAP) medium for the isolation of Campylobacter spp. from poultry carcasses.

Pork skin inoculated with a nalidixic acid-resistant strain of Campylobacter jejuni was subjected to three treatments to determine the effect of storage temperature, oxygen concentration, and drying on survival of the organism. Survival rate was determined for each treatment by enumeration over a 48-h period on Brucella agar containing nalidixic acid. Of the treatments studied, chilling with forced ventilation and storage at 20°C caused significant reductions in numbers of survivors. The results of this study confirm reports by other investigators that conventional forced ventilation chilling of pork carcasses has the beneficial effect of reducing skin surface Campylobacter contaminants.

An MPN procedure was used to determine the presence of Campylobacter fetus subsp. jejuni in poultry giblets. This procedure consists of (a) subculturing a sample in Brucella broth supplemented with 0.15% agar, 0.05% sodium pyruvate and the following antimicrobial agents per liter: vancomycin 10 mg, trimethoprim 5 mg, polymyxin B sulfate 2,500 IU, amphotericin B 2 mg and cephalothin 15 mg and (b) subsequent streaking of a loopful of Brucella broth held at 42 C for 48 h on plates of Brucella agar supplemented with 10% defibrinated horse blood and the concentrations of antimicrobial agents identified above. C. fetus subsp. jejuni was present in 85% of the chicken livers and in 89% of the chicken gizzards obtained immediately after evisceration. The organism was not recovered from samples treated with chlorinated water. C. fetus subsp. jejuni was not recovered from raw milk (bulk tank samples or individual cow samples) or from beef ( infraspinatus or biceps femoris muscles).

Campylobacter jejuni is a thermophilic and microaerophilic enteric pathogen associated with poultry. Biofilms may be a source of C. jejuni in poultry house water systems since they can protect constituent microorganisms from environmental stress. In this study, the viability of C. jejuni in biofilms of gram-positive chicken house isolates (P1, Y1, and W1) and a Pseudomonas sp. was determined using a cultural method (modified brucella agar) and direct viable count (DVC). Two-day biofilms grown on polyvinyl chloride (PVC) coupons in R2A broth at 12 and 23 degrees C were incubated with C. jejuni for a 6-h attachment period. Media were then refreshed every 24 h for 7 days to allow biofilm growth. Two-day biofilms of P1, Y1, and Pseudomonas spp. enhanced attachment (P < 0.01) of C. jejuni (4.74, 4.62, and 4.78 log cells/cm2, respectively) compared to W1 and controls without preexisting biofilm (4.31 and 4.22 log cells/cm2, respectively). On day 7, isolates P1 and Y1 and Pseudomonas biofilms covered 5.4, 7.0, and 21.5% of the surface, respectively, compared to 4.9% by W1. Viable C. jejuni on the surface decreased (P < 0.05) with time, with the greatest reduction occurring on surfaces without a preexisting biofilm. The number of viable C. jejuni determined by DVC was greater than that determined by the cultural method, indicating that C. jejuni may form a viable but nonculturable state within the biofilm. Both DVC and the cultural method indicate that biofilms enhance (P < 0.01) the survival of C. jejuni during incubation at 12 and 23 degrees C over a 7-day period.

A selective-differential medium for isolation of Campylobacter jejuni from chicken carcasses was developed. The medium, Campy-Cefex, consisted of Brucella agar, 5% lysed horse blood, 0.05% ferrous sulfate (FeSO4.7H2O), 0.05% sodium pyruvate, 0.02% sodium bisulfite, and antibiotic supplements of 33 mg/L sodium cefoperazone and 200 mg/L cycloheximide. A total of 41 chicken carcass samples were plated onto Campy-Cefex, Campylobacter cefoperazone desoxycholate agar, and Campylobacter brucella agar plate media. Campy-Cefex proved as productive and selective as the other media. Campy-Cefex allowed for easier differentiation of C. jejuni from other flora compared to differentiation on Campylobacter cefoperazone desoxycholate agar medium. Differentiation of the non- Campylobacter spp. flora from Campylobacter spp. was the same on both Campy-Cefex and Campy-BAP. The selectivity for the organism on Campy-Cefex was better than on Campy-BAP. Growth of seven isolates of C. jejuni in microaerobic-(5% O2, 10% CO2, 85% N2) and dry ice-generated atmospheres was also assessed. After 24 h of incubation, the mean log10 CFU generated, using the same culture suspensions and medium, was 2.07 and 1.81 for the microaerobic and dry ice atmospheres, respectively. These two developments allow for simplification of materials and methods required to isolate C. jejuni from foods.

Campylobacter inoculation studies are limited without a suitable marker strain. The lurpose of this study was to screen Campylobacter strains (n=2073) obtained from poultry carcass rinses through the Centers for Disease Control and Prevention's National Antimicrobial Resistant Monitoring System for resistance to gentamicin and evaluate one strain's efficacy as a marker. A C. coli strain was found resistant to gentamicin at32 microg/ml. Gentamicin was incorporated into media (Campy-Cefex agar, Brucella agar, and blood agar) from 0 to 1000 microg/ml, and the upper level of gentamicin resistance was determined. C. coli strain's upper level of growth on Campy-Cefex plates, blood agar plates, and Brucella agar plates was 400, 300, and 200 pg/ml, respectively. Ceca and postpick carcass rinses were obtained and streaked onto Campy-Cefex agar at the above gentamicin levels to evaluate background microflora exclusion. Campy-Cefex agar containing gentamicin at 100 ag/ml prevented from the ceca, and reduced from the rinse, background microflora. The C. coli strain was orally or intracloacally inoculated into chicks. At 1, 3, and 6 weeks of age, inoculated broilers were removed and several tissue types sampled for the presence of the marker strain. At 6 weeks of age, 10 additional noninoculated penmates were sampled. The C. coli strain colonized chicks, disseminated to body tissues, colonized penmates, and persisted throughout the 6-week grow-out. The C. coli strain's unique characteristic, being resistant to high levels of gentamicin, allows for a marker that can be used in a wide range of Campylobacter research projects.

A selective enrichment-plating procedure was tested for the recovery and enumeration of Campylobacter jejuni from turkey eggs and meat. Enrichment was in brucella broth with ferrous sulfate, sodium metabisulfite, sodium pyruvate and five antimicrobial agents. Plating was on brucella agar supplemented with equine blood and antimicrobial agents. Incubation of tubes and plates was at 42°C in an atmosphere of 5% O2:10% CO2:85% N2. C. jejuni could be recovered from the enrichment broth when calculated initial cell numbers per ml of broth were as low as 0.3 to 3.3.

The following aspects of Campylobacter jejuni has been reviewed: characteristics of C. jejuni , its occurrence in foods, methods to quantitatively recover the organism from food, and heat injury and freeze-thaw stress of C. jejuni . C. jejuni can be heat injured in 0.1 M potassium phosphate buffer at 46°C. Heat injury can be demonstrated as the differential count between brucella agar plus ferrous sulfate, sodium metabisulfite and sodium pyruvate (FBP) and brilliant green 2% bile broth agar plus FBP. Heat-injured C. jejuni will grow on brucella agar containing either of the three antibiotic mixtures typically used to isolate C. jejuni . Heat-injured C. jejuni will repair (regain dye and bile tolerance) in brucella broth plus FBP. C. jejuni can be freeze-thaw stressed. This stress is demonstrated as a sensitivity to the antibiotic polymyxin B or incubation at 42°C. Addition of succinate and cysteine increased recovery of freeze-thaw stressed C. jejuni . Although the presence of injured/stressed C. jejuni in foods has not yet been detected, methods are now available to begin this search. The injury/stress process may explain the often encountered difficulty in isolating C. jejuni , especially low numbers, from foods.

Swab, rinse and excision sampling methods are commonly used for detection of microorganisms on poultry carcasses. Swabbing has been the most frequently reported sampling method for Campylobacter jejuni on poultry. We evaluated the three methods for C. jejuni detection on freshly processed poultry in the following ways: (a) the interior and exterior surfaces of half of a carcass were each thoroughly rubbed with separate swabs which were combined in a test tube containing 2 ml of appropriate medium; (b) 25 g of skin and tissue samples from neck and abdominal opening cut areas were deposited in a stomacher bag with 5 ml of brucella broth (BB) and stomached for 2 min; and (c) half carcasses were shaken for 1 min with 100 ml BB in plastic bags. One drop of each sample was streaked for isolation on brucella agar containing 10% defibrinated sheep blood and Skirrow antibiotics. Isolates were identified by microscopy and appropriate cultural tests. All three sampling techniques were essentially equivalent for detection of C. jejuni on fresh carcasses. However, when samples were stored frozen for 7 to 10 d to simulate transport conditions from sampling locations to the laboratory, the incidence of detection was significantly reduced. Use of cryoprotective agents was an effective method to preserve swab samples during frozen storage.