Escherichia coli O157:H7 populations in ruminants can be reduced by orange peel product feeding.

Foodborne pathogenic bacteria such as Escherichia coli O157:H7 are threats to the safety of beef. Citrus peel and dried orange pulp are by-products from citrus juice production that have natural antimicrobial effects and are often incorporated into least-cost ration formulations for beef and dairy cattle. This study was designed to determine if orange peel and pulp affected E. coli O157:H7 populations in vivo. Sheep (n = 24) were fed a cracked corn grain-based diet that was supplemented with a 50-50 mixture of dried orange pellet and fresh orange peel to achieve a final concentration (dry matter basis, wt/wt) of 0, 5, or 10% pelleted orange peel (OP) for 10 days. Sheep were artificially inoculated with 10(10) CFU of E. coli O157:H7 by oral dosing. Fecal shedding of E. coli O157:H7 was measured daily for 5 days after inoculation, after which all animals were humanely euthanized. At 96 h postinoculation, E. coli O157:H7 shedding was reduced (P < 0.05) in sheep fed 10% OP. Populations of inoculated E. coli O157:H7 were reduced by OP treatment throughout the gastrointestinal tract; however, this reduction reached significant levels in the rumen (P < 0.05) of sheep fed 10% OP diets. Cecal and rectal populations of E. coli O157:H7 were reduced (P < 0.05) by inclusion of both 5 and 10% OP diets. Our results demonstrate that orange peel products can be used as a preharvest intervention strategy as part of an integrated pathogen reduction scheme.

Orange peel products can reduce Salmonella populations in ruminants.

Salmonella can live undetected in the gut of food animals and be transmitted to humans. Animal diets can impact intestinal populations of foodborne pathogens, including Salmonella spp. Orange juice production results in a waste product, orange peel and orange pulp, which has a high nutritive value and is often included in cattle diets as a least-cost ration ingredient. Here we show that the inclusion of orange peel products reduced Salmonella Typhimurium populations in the gut of experimentally inoculated sheep. Sheep (n=24) were fed a cracked corn grain-based high grain diet that was supplemented with a 50%/50% (dry matter [DM], w/w) mixture of dried orange pellet and fresh orange peel to achieve a final concentration (DM, basis) of 0%, 10%, or 20% orange product (OP) for 10 days before inoculation with Salmonella Typhimurium. Sheep were experimentally inoculated with 10(10) colony forming units Salmonella Typhimurium, and fecal samples were collected every 24 h after inoculation. Sheep were humanely euthanized at 96 h after oral Salmonella inoculation. Populations of inoculated Salmonella Typhimurium were numerically reduced by OP treatment throughout the gastrointestinal tract, and this reduction only reached significant levels in the cecum (p<0.05) of sheep fed 10% OP diets. Apparent palatability issues decreased the consumption of OP in sheep fed 20% OP to intake levels below that of 10% OP (approximately 7% dry matter intake [DMI]/d feed refusal), thereby reducing the potential effects of OP feeding at this higher level. Our results demonstrate that orange peel and pellets are environmentally friendly and low-cost products that can be used as a pre-harvest intervention as part of an integrated pathogen reduction scheme.

Bacteriophage isolated from feedlot cattle can reduce Escherichia coli O157:H7 populations in ruminant gastrointestinal tracts.

Escherichia coli O157:H7 can live undetected in the gut of food animals and be spread to humans directly and indirectly. Bacteriophages are viruses that prey on bacteria, offering a natural, nonantibiotic method to reduce pathogens from the food supply. Here we show that a cocktail of phages isolated from commercial cattle feces reduced E. coli O157:H7 populations in the gut of experimentally inoculated sheep. A cocktail of phages was used in order to prevent the development of resistance to the phages. In our first in vivo study we found that our cocktail of phages reduced E. coli O157:H7 populations in the feces of sheep (p < 0.05) by 24 hours after phage treatment. Upon necropsy, populations of inoculated E. coli O157:H7 were reduced by phage treatment in both the cecum (p < 0.05) and rectum (p < 0.1). In our second in vivo study, several ratios of phage plaque-forming units (PFU) to E. coli O157:H7 colony-forming units (CFU) were used (0:1, 1:1, 10:1, and 100:1 PFU/CFU) to determine the most efficacious phage dose. A 1:1 ratio of phage to bacteria was found to be more effective (p < 0.05) than either of the higher ratios used (10:1 or 100:1). Ruminal levels of E. coli O157:H7 were not significantly reduced (p > 0.10) in any of the studies due to relatively low inoculated E. coli O157:H7 ruminal populations. Our results demonstrate that phage can be used as a preharvest intervention as part of an integrated pathogen reduction scheme.

E. coli O157 and Salmonella spp. in white-tailed deer and livestock.

Escherichia coli O157 and Salmonella spp. are among the leading causes of food-borne illness in the United Sates and bacteria have been isolated from numerous ruminant animal sources. The objective of this study was to assess the incidence of E. coli O157 and Salmonella spp. in white-tailed deer (Odocoileus virginianus) and livestock simultaneously grazing the same rangeland. Escherichia coli O157 was found in 1.25% of cattle, 1.22% of sheep, and 5.00% of water all from samples taken in September; however, no E. coli O157 was found in other sampled months or any species. Salmonella spp. were found in the highest quantities in deer and sheep, 7.69% and 7.32%, respectively. Salmonella spp. were also found in sampled water troughs, goats, and cattle (5.00%, 3.70%, and 1.25%, respectively). Further research examining pathogen distribution is needed to determine if white-tailed deer are a natural reservoir for these bacteria.

Microbiology of Pork Carcasses from Pigs with Differing Origins and Feed Withdrawal Times †.

The effects of buying source (terminal market, buying station, outdoor farm, and indoor farm), feed withdrawal before slaughter (0, 2, 4, and 6 h), and the incidence of punctured gastrointestinal (GI) tracts during evisceration on the numbers of pathogenic and spoilage bacteria on pork carcasses were determined. Of the 932 samples tested, a 0% incidence of the pathogens Salmonella spp., Listeria monocytogenes , Campylobacter spp., Clostridium perfringens , and Yersinia enterocolitica was found.A significant (P < 0.05) location effect was found, with the belly-sternum region having higher total plate counts than the head, pelvic cavity, and diaphragm regions of the carcass. A significant (P < 0.05) buying-source effect indicated that pigs from buying stations had higher lactic acid bacteria counts than pigs from outdoor and indoor farms. A buying source by fasting time interaction (P < 0.05) was noted for GI tract weights, with the indoor farm pigs having the highest incidence of ruptured GI tracts. The removal of feed prior to slaughter resulted in lighter GI tract weights and a lowered incidence of vicera rupture resulting in a lowered risk of pathogen contamination of carcasses. The extent of punctured GI tracts during evisceration was influenced by fasting time and buying source and may be useful in a HACCP system for the pork-processing industry.

Reduction of Microorganisms on Beef Surfaces with Electricity and Acetic Acid ‡.

This study determined the effect of a 2% acetic acid spray, pulsed-power electricity, pulsed-power electricity with a spray of sterile deionized water, and a combination of acetic acid spray and pulsed-power electricity in reducing the pathogens Escherichia coli O157 and Salmonella typhimurium and aerobic plate counts on beefsteaks compared to an inoculated control. Ten steaks per treatment were inoculated with 1 ml of E. coli O157 (l05 CFU/ml) or S. typhimurium (105 CFU/ml) for 2 min and then subjected to one of the five treatments. Acetic acid spray and acetic acid spray and pulsed-power electricity treatments significantly (P < .05) reduced the incidence of Escherichia coli O157 compared to inoculated controls and produced a 1-log CFU/cm2 reduction in the incidence of S. typhimurium . Ten steaks per treatment were also inoculated with 1 ml of S. typhimurium (l05 CFU/ml) for 2 min, treated with acetic acid spray, pulsed-power electricity and a sterile deionized water spray, or acetic acid spray and pulsed-power electricity and stored in an incubator at -2°C for 48 h to stimulate chill-cooler conditions in the beef industry. Acetic acid spray with and without pulsed-power electricity caused a 1-log CFU/cm2 reduction in S. typhimurium . These data indicate a need for the use of both 2% acetic acid and pulsed-power electricity in packing-house facilities to help achieve the goal of improved microbiological safety of beef.