This study investigated the potential causative agents for vacuum‐packaged pork that had shown gross package extension during a routine storage life study in a Canadian pork plant using both ...conventional and culture‐independent methods. The spoilage‐associated bacteria in purge samples from two packages were enumerated using selective media and profiled using 16S rDNA amplicon analysis. The presence of Clostridium estertheticum was detected using species‐specific real‐time PCR. An enrichment procedure was used to isolate C. estertheticum from one of the purge samples. The average population density in the two purge samples of total aerobes, lactic acid bacteria (LAB), coliforms and Brochothrix thermosphacta was 9·4, 9·1, 6·0 and 4·6 log CFU per ml respectively, as determined by plating. The estimated numbers of C. estertheticum were >7 log cells per ml. Clostridium estertheticum was recovered although the enrichment condition used for isolation favoured the growth of LAB more than that of Clostridium spp. Based on 16S rDNA amplicon analysis, the microbiota in the two purge samples had 64·7 and 20·7% of Clostridium spp., and 32·5 and 70·1% of LAB respectively.
Significance and Impact of the Study
Blown pack spoilage of vacuum‐packaged meat may lead to severe economic losses and is often associated with beef, venison and lamb. This study is the first to report vacuum‐packaged chilled pork can also be subject to blown pack spoilage, and data support the conclusion that the causative agent is likely Clostridium estertheticum. The lysozyme‐digestion step greatly improved the isolation efficiency for C. estertheticum, a spore‐forming anaerobic organism that has been proven to be difficult to recover. This method can be used for isolating spore‐forming organisms from food samples.
Significance and Impact of the Study: Blown pack spoilage of vacuum‐packaged meat may lead to severe economic losses and is often associated with beef, venison and lamb. This study is the first to report vacuum‐packaged chilled pork can also be subject to blown pack spoilage, and data support the conclusion that the causative agent is likely Clostridium estertheticum. The lysozyme‐digestion step greatly improved the isolation efficiency for C. estertheticum, a spore‐forming anaerobic organism that has been proven to be difficult to recover. This method can be used for isolating spore‐forming organisms from food samples.
Aims: This study aimed to determine the survival of Escherichia coli strains during steam and lactic acid decontamination interventions currently used by the beef-processing industry, and to ...determine their heat resistance. Methods and Results: Strains were grouped into cocktails of five strains each differing in their RAPD patterns for subsequent identification. Steam and lactic acid treatments on meat reduced cell counts of E. coli strain cocktails by 90-99%. The 20 slaughter plant isolates exhibited only minor variation in their resistance to steam and lactic acid treatments but were more resistant than reference strains (three strains) or isolates from live cattle (seven strains). D₆₀ values of strains from live cattle, and reference strains ranged from 0·1 to 0·5 min, in keeping with literature data. However, D₆₀ values of current slaughter plant isolates ranged between 15 for E. coli DM18.3 and 71 min AW 1.7. Cell counts of E. coli AW 1.7 were reduced by <5 log₁₀ CFU g⁻¹ in ground beef patties cooked to an internal temperature of 71°C. Conclusions: Strains of E. coli that survive cooking of ground beef to the recommended internal temperature of 71°C can be isolated from beef-processing facilities. Significance and Impact of the Study: Pathogen interventions in current commercial beef slaughter may select for extremely heat-resistant strains of E. coli.
A total of 800 meat and poultry products were purchased from the retail marketplace in Edmonton, Alberta, Canada. The products consisted of raw ground beef, chicken legs, pork chops, and ready-to-eat ...fermented sausage, roast beef, processed turkey breast, chicken wieners, and beef wieners. The samples were analyzed to determine the prevalence of Shiga toxin-producing Escherichia coli, Salmonella, Campylobacter spp., and Listeria monocytogenes. Shiga toxin-producing E. coli O22: H8 was found in one raw ground beef sample. Salmonella and Campylobacter were found in 30 and 62% of raw chicken legs, respectively. L. monocytogenes was found in 52% of raw ground beef, 34% of raw chicken legs, 24% of raw pork chops, 4% of fermented sausages, 3% of processed turkey breast, 5% of beef wieners, and 3% of chicken wieners. The occurrence of pathogens in this study is similar to that in retail products in many other international locales.
During the first week of the posthatching period, before the immune system is mature enough to produce its own B lymphocytes, a chick’s humoral immunity depends on maternal antibodies (IgY) received ...from the egg yolk. During incubation and after hatching, the yolk sac (YS) membrane transfers nutrients (including IgY) from the egg yolk to the developing embryo or newly hatched chick. The objective of this study was to determine the effects of breeder flock age on the total IgY content of egg yolks and chick YS from a commercial broiler breeder strain. Hatching eggs from the same broiler breeder flock were collected at 32, 40, and 55 wk of age. One group of eggs per flock age was used to determine the egg yolk total IgY content. Another group of eggs was incubated for 21.5 d, and upon hatching, the YS of newly hatched chicks were collected to determine the total IgY content. Egg and egg yolk weight increased with flock age, but YS weights did not reflect egg yolk weight. The total IgY content per gram of egg yolk increased with flock age; this fact plus the observed yolk weight increase with flock age notably increased the total IgY contained in yolks of eggs laid by 55-wk-old breeders. However, chicks hatching from 55-wk-old breeders had less IgY per gram of YS than chicks from 32- and 40-wk-old breeders. Whether there are differences in the rates of YS absorption between chicks of different breeder ages is unknown. This research provided total IgY values for broiler breeder egg yolk and chick YS of a commonly used meat-type chicken strain. Differences in egg yolk and YS total IgY contents due to flock age in this type of bird had not been previously reported. Research on the physiological consequences of YS absorption rates in chicks from different breeder ages is advised.
An experiment was conducted to determine whether spraying hatching eggs with electrolyzed oxidizing (EO) water would decrease eggshell microbial load and hence improve hatchability, chick quality, ...and broiler growth performance. Eggs were collected from a broiler breeder flock; half the eggs were sprayed with EO water and the other half were left untreated. Enterobacteriaceae and total aerobic bacteria present on the eggshells of eggs from both treatments were enumerated. The eggs were incubated, and the broiler chicks were grown out to 39 d. Eggshell microbial load was significantly decreased by spraying the eggs with acidic EO water before incubation, with no effect on cuticle structure as measured by egg weight (moisture) loss, normal embryonic development, and hatchability. Chick quality, as determined by visual assessment and BW at the time of hatch, was also not affected. However, broiler mortality during the first 2 wk of the production period was significantly reduced in the chicks that hatched from eggs sprayed with EO water compared with chicks hatching from control eggs. The ability of EO water to reduce eggshell microbial load without negatively affecting hatchability or chick quality may make it a useful product for hatching egg sanitation.
Core Ideas
Lysimeters aid subsurface water quality assessments in long‐term nutrient management plots.
Broiler litter rates affected few leachate quality parameters during a continuous 8‐yr period.
...Leachate water quality was affected by season during a continuous 8‐yr period.
In regions with concentrated broiler (Gallus gallus) production, land application is a useful means of managing broiler litter (BL). However, surface and subsurface water quality issues may arise when continued annual BL application to fields occurs for extended periods. The application of manure follows seasonal guidelines for surface water quality protection. The objective of this study was to evaluate the effects of BL rate (0, 5.6, and 11.2 Mg litter ha−1) and season on drainage and leachate water quality over an 8‐yr period (2003–2011) in the Ozark Highlands with karst geology using automated, equilibrium‐tension lysimeters. During the 8‐yr period, seasonal drainage was unaffected by season or BL rate, averaging 118 mm per season. Averaged across BL rates, seasonal leachate pH, electrical conductivity (EC), flow‐weighted mean (FWM) NO3–N, dissolved organic C, S, and Zn concentrations, and NH4–N, Cu, Fe, and Se loads differed (P < 0.05) among seasons. Averaged across seasons, seasonal leachate EC, FWM PO4–P, total P, and S concentrations, and Ni load differed (P < 0.05) among BL rates. With the exception of As and Se, seasonal FWM leachate Cd, Cr, Cu, and NO3–N concentrations were at least five times smaller than their maximum contaminant level for drinking water during any of the four seasons. Since rainfall patterns seasonally change in many regions of concentrated poultry production, seasonal differences in the leachate water quality response to continuous annual application of BL are important to help tailor best management practices to protect soil and water resources in regions underlain by karst geology.
Objective: To investigate the effect of probiotic capsules on plasma lipids. Design: A randomized, single-blinded, placebo-controlled, parallel-arm trial. Subjects: Fifty-five normocholesterolemic ...subjects ages 18-36 (33 premenopausal women and 22 men). Intervention: Each subject consumed either three probiotic capsules each containing a total of 10(9) colony-forming units Lactobacillus acidophilus and Bifidobacterium longum and 10-15 mg fructo-oligosaccharide or three placebo capsules daily for 2 months (men) or two menstrual cycles (women). Plasma lipids were measured before and following the intervention (during the early follicular phase for women). Results: Plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglyceride were not altered by consumption of probiotic or placebo capsules and were not different between treatment groups following the intervention. Conclusions: These results do not support a beneficial effect of Lactobacillus acidophilus strain DDS-1 and Bifidobacterium longum strain UABL-14 on plasma lipids in normocholesterolemic young women and men.
In Canada, there is a zero tolerance for Listeria in a 125-g sample of product in which growth of Listeria monocytogenes can occur, and a limit of ≤100 CFU/g in ready-to-eat (RTE) food products that ...support limited growth during the stated shelf life and/or RTE refrigerated foods with a shelf life of ≤5 days. L. monocytogenes can form filaments in response to pH and osmotic, atmospheric, and temperature stress, which can result in an underestimation of the risk of RTE foods as filaments form single colonies on plate count agars but can divide into individual cells once the stress is removed. The objective was to investigate the filamentation characteristics of three strains of L. monocytogenes exposed to saline, acidic, basic, and simultaneous acidic and saline environments at 3°C. After 4 days at 3°C, log-phase cells grown in tryptic soy broth (TSB) were longer than cells grown at 15°C, and 68% of cells were below the reference value of the 90th percentile of control cultures. When cultures growing at 3°C were exposed to additional stresses, increases in the proportion and length of filaments in the population were observed, while increases in log CFU per milliliter were reduced. After 4 days of incubation at 3°C, the log CFU per milliliter of L. monocytogenes increased by 1.1 U in TSB and 0.4 to 0.5 U in TSB with 4% NaCl, TSB with a pH of 6.0 with 4% NaCl, and TSB with a pH of 5.5. Moreover, the longest 10% of cells were 6.4 to 8.5 times longer than control cells, and only 20 to 30% of cells were below the reference value. Cultures grown in TSB at pH 6.0 with 4% NaCl experienced more sustained filamentation than cultures grown in TSB with 4% NaCl, but less than cultures grown in TSB at pH 6.0. The mechanism involved in filamentation could be different for cells exposed to NaCl than exposed to acid, and additional stress might not necessarily result in more extensive filament formation. These findings contribute to a better understanding of the widespread potential of filament formation and the potential implications for food safety.
Aims: To identify sources of Escherichia coli on beef by characterizing strains of the organism on animals, equipment and product at beef‐packing plant.
Methods and Results: Generic E. coli were ...recovered from hides, carcasses, beef trimmings, conveyers and ground beef during the summer of 2001 (750 isolates) and winter of 2002 (500 isolates). The isolates were characterized by Random Amplification of Polymorphic DNA (RAPD). The numbers of E. coli recovered from dressed carcasses were less than the numbers recovered from hides. The numbers recovered from chilled carcasses were too few for meaningful analysis of the strains present on them but the numbers recovered from trimmings and ground beef were larger. The RAPD patterns showed that the majority of isolates from hides, carcasses, beef trimmings, conveyers and ground beef were of similar RAPD types, but a few unique RAPD types were recovered from only one of those sources. The E. coli populations present on the hides of incoming animals and in the beef‐processing environment were highly diverse. Randomly selected E. coli isolates from each of the five sources were further characterized by pulsed‐field gel electrophoresis (PFGE). Most genotypes of E. coli defined by PFGE corresponded to the E. coli types defined by RAPD.
Conclusions: The hides of the incoming animals appeared to be only one of the sources of the E. coli on trimmings and in ground beef, as additional sources were apparently present in equipment used for carcass breaking.
Significance and Impact of the Study: This study indicates that hazardous microbiological contamination of meat may occur after the dressing of carcasses at commercial beef‐packing plants, which suggests that attention should be given to the control of the contamination of meat during carcass breaking as well as during the dressing of carcasses.
PDF
