Adaptation of Listeria in liquid egg containing sucrose resulting in survival and outgrowth.

Survival of Listeria species was tested in liquid egg products such as albumen, yolk, whole egg and whole egg containing 25% sucrose. At an incubation temperature of 4 degrees C Listeria survived in all products, and even increased slightly in yolk, whole egg and whole egg containing 25% sucrose. However, at 20-22 degrees C, in whole egg containing sucrose, a rapid an dramatic decrease in numbers of Listeria was observed. Following this initial decrease, an increase in the numbers of Listeria was observed. The ability to grow in liquid egg containing sucrose was maintained upon reinoculation into a freshly prepared product. However, this property disappeared after subculturing in brain heart infusion broth. The significance of these findings is discussed.

Prevention of colonization by Salmonella enteritidis PT4 in broiler chickens.

Field experiments in The Netherlands and in Scandinavian countries have shown that an undefined microflora originating from SPF adult poultry will reduce considerably the colonization of young chicks by Salmonella. A commercial product from this so-called Nurmi concept, Broilact, was studied for its effectiveness in preventing infection of broilers with Salmonella enteritidis PT4 (S.e.). Two trials were carried out, in which the birds were exposed to S.e. via 'seeder' birds placed among them. The trial period was 21 days and each week one third of the chicks was killed and their caecal contents examined for salmonellas. The results of the first trial can be summarized as follows. (1) After 2 weeks the number of 'seeder' birds carrying the Salmonella decreased sharply; (2) the proportion of infected chicks in the Broilact-treated group was lower than in the non-treated group; (3) Counts of S.e. in the non-treated group were higher than in the Broilact group. Results of the second trial were comparable, although no salmonellas could be isolated after the second week.

Explosive increase of Salmonella Java in poultry in the Netherlands: consequences for public health.

In the Netherlands Salmonella Paratyphi B variant Java increased in poultry from less than 2% of all isolates before 1996 to 60% in 2002. Despite exposure to contaminated meat is high, human patients with Java infection are rare (0.3% of all isolates). However, 50% of the human isolates showed PFGE profiles identical to the poultry clone. Resistance to flumequin in S. Java increased from 3% between 1996-2000 to 19% in 2001, and 39% in 2002, while that of other serotypes in poultry remained at about 7%. S. Java is also fast becoming less sensitive to ciprofloxacin.

Heritabilities of and genetic relationships between salmonella resistance traits in broilers.

Using experimental infections, three traits for salmonella resistance were studied: mortality, survival time (in animals that died by infection), and quantitative cecal salmonella carriage at the end of the rearing period (in animals that did not die). In total, 548 animals were used; mortality was 29.2%, mean survival time was 5.97 d (n = 160), and the mean 10log of colony forming units per gram of cecal contents was 1.62 (n = 387). Genetic parameters were evaluated in bivariate threshold-linear models to account for the selective measurement of survival time and cecal carriage. Heritabilities were .06 for survival time, .09 for cecal carriage, and .12 for mortality. The genetic correlation between mortality and cecal carriage was weak (.26), which suggests that these traits are largely controlled by different genes. The genetic correlation between mortality and survival time was relatively strong (-.68). Simultaneous study of multiple traits seems to be of particular importance in judging epidemiological consequences of a possible selection for resistance. Results here indicate that selection on decreased mortality could be unfavorable for the spread of salmonella because the resulting correlated increase in survival time, implying longer shedding by infected animals, is relatively stronger than the correlated decrease in level of cecal carriage. Selection to reduce the level of cecal salmonella carriage could be done while keeping survival time constant, if so desired, because the correlation between these traits is weak (-.15).

Cecal carriage of Campylobacter and Salmonella in Dutch broiler flocks at slaughter: a one-year study.

From March 1992 to March 1993, 187 Dutch broiler flocks were screened to assess their Campylobacter and Salmonella carriage. Every 4 wk at least 10 flocks, at three different slaughterhouses, were screened for presence of these bacteria. Twenty-five cecal samples were taken from each flock. Campylobacter spp. were isolated from 153 out of 187 broiler flocks (82%). Campylobacter carriage of flocks showed seasonal variation, with the highest contamination rate (100%) during the period June to September and the lowest (50%) in March. Salmonella carriage of the flocks did not show a distinct seasonal variation. Salmonella spp. were isolated from 49 out of 181 broiler flocks (27%). A positive correlation was found between Campylobacter and Salmonella colonization within flocks. Data on farming conditions and husbandry practices were studied to identify possible risk factors for Campylobacter and Salmonella colonization of Dutch broiler flocks.

Salmonella decontamination of broiler carcasses with lactic acid, L-cysteine, and hydrogen peroxide.

Experiments on salmonella decontamination of broiler carcasses with lactic acid, L-cysteine, and hydrogen peroxide were performed. Treatment with lactic acid (1%) and hydrogen peroxide (.5%) resulted in a 4-log cycle reduction in colony forming units of Salmonella typhimurium both with pure cultures and with artificially inoculated broiler carcasses. L-cysteine was nonbactericidal in these experiments.

The effect of flavophospholipol (Flavomycin) and salinomycin sodium (Sacox) on the excretion of Clostridium perfringens, Salmonella enteritidis, and Campylobacter jejuni in broilers after experimental infection.

Intestinal colonization and shedding of pathogenic bacteria in animal feces is an important factor in both human food safety and animal health. The effect of broiler feed additives flavophospholipol (FPL; Flavomycin, bambermycins) and salinomycin sodium (SAL; Sacox) given singly on the excretion of Salmonella enteritidis, Campylobacter jejuni, and Clostridium perfringens was studied following controlled infection. The incidence of shedding (number of birds with positive fecal cultures) and the degree of shedding (cfu per gram of feces in positive birds) were measured to determine the influence of these two common feed additive antibiotics on shedding rates of potential pathogens. A total of 216 Ross broiler chickens, housed in battery cages, were fed either an unmedicated feed (controls), feed containing FPL, or feed containing SAL. Feed treatment groups were subdivided into three bacterial challenge groups of 24 chicks, each receiving only one of the pathogens. Bacterial challenge was administered orally on Days 11 and 12 for Salmonella and Campylobacter and on Days 2 and 3 for Clostridium. Fecal samples were collected weekly up to 6 wk of age and cultured for presence of the target organism. The shedding rate was determined by decimal dilutions of the fecal samples. Feeding FPL resulted in a reduced (P < or = 0.05) degree and incidence of Salmonella and Clostridium shedding at 6 wk. Feeding SAL reduced (P < or = 0.05) the incidence of Salmonella shedding at 6 wk. Neither feed additive affected the incidence nor the degree of Campylobacter shedding. The results of this study indicate that these feed additives may reduce the incidence of these potential human and animal pathogens in preslaughter broilers.

The effect of different bird washers on the microbiological quality of broiler carcasses.

The effect of spray washers and inside-and-outside bird washers on the microbiological quality of broiler carcasses was examined in 13 poultry slaughterhouses. The carcasses were sampled by means of the carcass rinse method; total and Enterobacteriaceae counts were estimated. The decrease in total and Enterobacteriaceae counts due to spray washing was as high as with the use of an inside-and-outside bird washer. From this investigation the conclusion can be drawn that the use of an inside-and-outside bird washer does not guarantee a better microbiological cleaning of the inside of the carcasses made 'mandatory' by EEC regulations.

In vitro susceptibility of Campylobacter and Salmonella isolates from broilers to quinolones, ampicillin, tetracycline, and erythromycin.

Recently, an increased resistance of Campylobacter to fluoroquinolones, a newer class of antimicrobial agents in both human and veterinary medicine, has been reported. Campylobacter isolates (617) from 150 broiler flocks were tested for their susceptibility to cephalothin (control), ampicillin, tetracycline, erythromycin, and the quinolones nalidixic acid, flumequine, enrofloxacin, and ciprofloxacin by a disc diffusion method. Almost complete cross-resistance was found between the quinolones tested. Campylobacter isolates (181, 29%), originating from 55 flocks (37%), were quinolone resistant. Salmonella isolates (94) from 40 flocks were also tested for their antimicrobial susceptibility. Eight isolates (8.5%), from three broiler flocks (7.5%), showed resistance to nalidixic acid and flumequine (and tetracycline), but not to ciprofloxacin or enrofloxacin.

Reduction of salmonella infection of broilers by spray application of intestinal microflora: a longitudinal study.

The Nurmi concept for diminishing salmonella infection of poultry by application of gastrointestinal microflora from adult birds into newly hatched chicks was tested in a field study in which 8 million broilers were involved. Half of the 284 flocks was treated in the hatchery by spray application of an undefined microflora propagated in SPF chicks. A significant reduction in salmonella-contaminated flocks, as well as in the number of infected broilers in these flocks was demonstrated. No undesirable side effects were detected. It was concluded that hygienic improvements in transportation and slaughtering of broilers are needed in order to maintain the reduced salmonella contamination rate.

[A comparison of 3 isolation methods for the demonstration of Salmonella bacteria in fryer-chicken feed]. / Een vergelijking van drie isolatie-methoden voor het aantonen van Salmonella-bacteriën in braadkuikenvoeders.

167 Samples of fryer chicken feed were examined for the presence of Salmonella using three different methods of isolation. These methods consisted in the isolation of Salmonella using procedure ISO-3565, this method but supplemented by treatment with hydrogen sulphide (ISO + H2S) and the membrane filter disc immuno-immobilisation method (MFDI). In addition, thirty-three samples were examined by the ISO and ISO + H2S techniques. 200 Grams of feed of each sample were studied. A total number of fifteen samples (7.5 per cent) were found to be positive for Salmonella, thirteen of which were examined by the ISO-3565 method of isolation of Salmonella. When the other methods were employed, only five samples were found to be positive for Salmonella using the ISO + H2S technique and two using the MFDI method. When all three methods were used, they failed to produce positive results in each sample which had been found to be positive for Salmonella. The differences in the number of positive samples were found to be significantly (P less than 0.01) in favour of the ISO method. When a choice has to be made between the method used in the detection of Salmonella, the ISO-3565 method of isolating Salmonella is to be preferred.

[The use of flocculation sludge in poultry feed. Chemical and microbiological composition]. / Het gebruik van vlokkingsslib in pluimveevoeders. Chemische en microbiologische samenstelling.

For the purpose of making inventories, the chemical and microbiological composition of samples of flocculated sludge of poultry, pig and cattle-stock slaughter-houses were examined. This was required to study the possibilities of using flocculated sludge as raw material in animal feed. Chemical studies showed that the dry matter (dm) levels of the various specimens of sludge varied markedly. (Broiler sludge 7.1% of dm, pig sludge 7.5%, cattle-stock sludge 5.5% and laying-hen sludge 13.3%). Broiler- and laying-hen sludge contained more crude fat than did the other samples of sludge. Measured by the concentrations of lysine, methionine and cystine, the sludge product was most similar to the protein of meal-and-bone meal and soy-bean meal. The iron content of almost all samples examined was very high. In view of the current standards for concentrations of metal in complete animal feeds, the concentrations of iron and lead will have to be taken into account in using this sludge product. The proportion of total polymers in the fat fractions of samples of sludge varied from 2.4% to 39.2%, less than 10% only being observed in two samples. The microbiological composition of broiler and pig sludge did not differ. Both the total aerobic bacterial count and the number of Enterobacteriaceae, Escherichia coli and Salmonella were found to be high. Species of Campylobacter were not isolated; however, a number of samples were found to be positive for adenovirus. Prior to deciding to use flocculated sludge in livestock feeding, the product will have to undergo thorough decontamination.

[Explosive increase in Salmonella java in poultry. Consequences for public health]. / Explosieve toename van Salmonella Java in pluimvee. Consequenties voor de volksgezondheid.

In the Netherlands S. Paratyphi B variation Java increased in poultry from less than 2% of all isolates before 1996 up to 40% in 2001. This development in poultry runs in parallel with that in Germany and appears not to occur in other European countries. A German study shows that in the late nineties it concerns isolates of only one multi-resistant clone of Java (in Holland as well) whilst isolates before the middle nineties were genetically much more heterogeneous and sensitive to antibiotics. Although the exposition of humans to contaminated poultry meat is relatively high, human patients with a Java infection are rare. Treatment of poultry flocks with quinolones was about 13% in 2000-2001. Resistance to flumequin of Java increased from 3% between 1996-1999 to 20% between 2000-2002 whilst that of other serotypes in poultry remained about 7%. Java is also fast becoming less sensitive to ciprofloxacin which is the antibiotic of first choice in serious cases of salmonellosis. The ministries of public health, agriculture and the production boards, with their research institutes, together with the poultry meat production chain integrations have recently decided to work together in order to determine the public health importance of the Java epidemic in poultry and finding measures for effective control in the poultry industry.

Evaluation of the "testing and scheduling" strategy for control of Campylobacter in broiler meat in The Netherlands.

"Testing and scheduling" has been proposed as a strategy for control of Campylobacter in broiler meat. By this strategy, flocks with high numbers of Campylobacter in fecal samples would be diverted away from fresh meat production at the entrance of the broiler meat processing plant. Risk assessment studies suggest that this would effectively decrease human health risks, if these flocks are responsible for the meat products with the highest Campylobacter numbers. To investigate the effect of this control strategy, the numbers of Campylobacter were determined in fecal samples from transport containers, and in cecal and breast meat samples from birds in 62 broiler chicken flocks. Results from direct plating and enrichment were combined by a statistical method that allows the inclusion of censored data. As the implementation of "testing and scheduling" requires a rapid on-site test to detect high numbers of Campylobacter, a lateral flow immuno-assay (LFA) was developed and applied to the fecal samples collected from containers. The Campylobacter prevalence in broiler flocks in the autumn of 2007 was found to be 85.4% by traditional microbiological methods. Campylobacter could be isolated from breast meat samples from 42% of the flocks. There was limited agreement between Campylobacter results for the three types of samples and weak correlation between the quantitative results for fecal or cecal samples and meat samples. Agreement between the results of LFA and traditional methods was poor. These findings do not support the implementation of "testing and scheduling" as a practical control strategy, because of both measurement uncertainties and shortcomings in understanding the dynamics of transmission and survival of Campylobacter in the broiler meat processing plant. The limited correlation between Campylobacter contamination of cecal samples and breast meat samples, as observed in this study, suggests that cecal samples are no good indicator for human exposure to Campylobacter.

The effect of a commercial UV disinfection system on the bacterial load of shell eggs.

AIMS: To study the effect of UV irradiation on the bacterial load of shell eggs and of a roller conveyor belt. METHODS AND RESULTS: The natural bacterial load on the eggshell of clean eggs was significantly reduced by a standard UV treatment of 4.7 s; from 4.47 to 3.57 log CFU per eggshell. For very dirty eggs no significant reduction was observed. Eggs inoculated with Escherichia coli and Staphylococcus aureus (4.74 and 4.64 log CFU per eggshell respectively) passed the conveyor belt and were exposed to UV for 4.7 and 18.8 s. The reduction of both inoculated bacteria on the eggshell was comparable and significant for both exposure times (3 and 4 log CFU per eggshell). Escherichia coli was reduced but still detectable on the conveyor rollers. The internal bacterial contamination of eggs filled up with diluent containing E. coli or S. aureus was not influenced by UV irradiation. CONCLUSIONS: There is a significant lethal effect of UV irradiation on the bacterial contamination of clean eggshells and recent shell contamination, contamination of rollers can be controlled and the internal contamination of eggs is not reduced. SIGNIFICANCE AND IMPACT OF THE STUDY: The penetration of UV into organic material appears to be poor and UV disinfection can be used as an alternative for egg washing.

Resistance of broiler outbred lines to infection with Salmonella enteritidis.

Salmonella infections originating from poultry are one of the major causes of food-borne disease. For the control of salmonella in poultry a multifactorial approach is more likely to be effective, and the genetic resistance of poultry breeds to salmonella infections may be a valuable contribution. Experimental Salmonella enteritidis infections were examined in three different broiler outbred lines: the FC line, which had been selected for feed conversion efficiency; the R line, which had been selected for growth rate; and the C line, a commercially available line. The FC line had the highest mortality rate after intramuscular inoculation with 5 x 10(6) colony forming units (CFU) of S. enteritidis at 2 weeks of age (40% versus 21 and 20% in the other lines). However, at slaughter age, the number of birds carrying salmonella in caecal contents, and the concentration of salmonella in the caecal contents, was lowest in the FC line. The FC and R lines were compared by inoculation with doses ranging from 10(2) to 10(7) CFU S. enteritidis. At sublethal doses (10(5) CFU or less), the FC line carried significantly less salmonella in caecal contents and the rate of systemic infection was lower. The start of shedding was also delayed compared with the R line. At doses of 10(6) CFU S. enteritidis or higher, there were no differences in salmonella carriage between the lines, and the FC line showed higher mortality. In conclusion, resistance to mortality and resistance to the carriage of S. enteritidis do not necessarily coincide within lines, as the FC line showed high mortality but low carriage, both in survivors of high infection doses and in all birds at lower infection doses.

Epidemiology of Campylobacter spp. at two Dutch broiler farms.

Broiler flocks on two Dutch poultry farms were screened weekly for the presence of campylobacter in fresh caecal droppings during eight consecutive production cycles. Hatchery and fresh litter samples were taken at the start of each new cycle. Water, feed, insects, and faeces of domestic animals, present on the farms were also included in the sampling. Penner serotyping of isolates was used to identify epidemiological factors that contribute to campylobacter colonization in the broiler flocks. Generally, broiler flocks became colonized with campylobacter at about 3-4 weeks of age with isolation percentages of 100%, and stayed colonized up to slaughter. A similar pattern of serotypes was found within the various broiler houses on one farm during one production cycle. New flocks generally showed also a new pattern of serotypes. Most serotypes isolated from the laying hens, pigs, sheep and cattle were different from those isolated from the broilers at the same time. Campylobacter serotypes from darkling beetles inside the broiler houses were identical to the ones isolated from the broilers. No campylobacter was isolated from any of the hatchery, water, feed or fresh litter samples. Conclusive evidence of transmission routes was not found, but results certainly point towards horizontal transmission from the environment. Horizontal transmission from one broiler flock to the next one via a persistent contamination within the broiler house, as well as vertical transmission from breeder flocks via the hatchery to progeny, did not seem to be very likely.