Pre-Chill Spray of Chicken Carcasses to Reduce Salmonella typhimurium

A test chamber was designed and constructed and prechill chicken carcasses inoculated with Salmonella typhimurium were treated in it. They were sprayed with tap water, 0.85% sodium chloride (NaCl), 5% or 10% trisodium phosphate (TSP), 5% or 10% sodium bisulfate (SBS), 0.1% cetylpyridinium chloride (CPC), or 1% lactic acids (LAC) at 207, 345 or 827 kPa pressure for either 30 or 90 sec exposure time. Samples were taken from carcass wash water to determine the most probable number of Salmonella. Compared to tap water spraying, 0.85% NaCl spraying did not significantly reduce Salmonella. The greatest reductions of S. typhimurium, by 10% TSP, 10% SBS, 0.1% CPC or 1% LAC spraying, were 3.7, 2.4, 1.6 or 1.6 log in 90 sec treatments, respectively.     

Salmonella typhimurium Attached to Chicken Skin Reduced Using Electrical Stimulation and Inorganic Salts

Chicken skins inoculated with Salmonella typhimurium at 1 × 10⁸ CFU/mL were subjected to chemical or electrical treatments (4 mA/ cm² current, 1 kHz frequency and 50% duty cycle) for 10 min in 1% sodium chloride (NaCl), sodium carbonate (Na₂CO₃), or trisodium phosphate (Na₃PO₄ 12H₂O or TSP). Salmonellae on chicken skins and in treatment solutions and rinsing water were enumerated with microbiological platings. Chicken skin was also examined using scanning electron microscopy.S. typhimurium attached to skins were reduced by 90% after electrical treatments in 1% NaCl, Na₂CO₃, or TSP, while the reduction ranged from 34% to 76% in groups treated by the salts alone.     

Trisodium Phosptiate (TSP) Treatment of Beef Surfaces to Reduce Escherichia coli O157:H7 and Salmonella typhimurium

Trisodium phosphate (TSP) was evaluated for removing attached E. coli O157:H7 and S. typhimurium from beef surfaces using microbiological plating and scanning electron microscopy (SEM). Both fat and fascia surfaces were exposed to 10⁹ CFU/mL of each inoculum for 15 min and rinsed with 10% TSP solution (10°C) for 15 sec. Compared to controls, the level of E. coli O157:H7 was 1.35 and 0.92-logs lower on TSP-treated fat and fascia surfaces, respectively by plating. .S. typhimurium was 0.91- and 0.51-logs lower, respectively. By SEM, TSP-treated fabcia surfaces showed 1.39-log and 0.86-log reductions in E. coli O157:H7 and S. typhimurium, respectively. Overall, TSP was more effective on removing E. coli O157:H7 than S. typhimutium and more efficient in removing both bacteria from fat surfaces than from fascia.     

Efficacy of Cetylpyridinium Chlorine on Salmonella Typhimurium and Escherichia coli O157:H7 in Immersion Spray Treatment of Fresh-Cut Lettuce

Fresh‐cut lettuce inoculated with Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 was treated using cetylpyridinium chlorine (CPC) solution in a laboratory‐scale immersion spray system. With 0.7 kg/cm² spray pressure and 1.5‐min spray time (ST), both bacteria were significantly reduced (P < 0.05) in 0.1% to 0.3% CPC spray treatments, compared with water spray controls. At the same ST, increasing spray pressure from 0.7 to 2.1 kg/cm² further reduced bacteria by 0.5 to 1.5 log colony‐forming units (CFU)/g. The 0.2% and 0.3% CPC treatments resulted in the greatest reduction of S. serovar Typhimurium and E. coli O157:H7, respectively. Similar bacterial reduction could be achieved using shorter ST with extended post‐spray exposure time. No color change on the lettuce was observed after CPC treatment.     

Quaternary Ammonium Compounds Inhibit and Reduce the Attachment of Viable Salmonella typhimurium to Poultry Tissues

Quaternary ammonium compounds (QAC) were studied to characterize their inhibition and reversal of S. typhimurium's strong attachment to chicken skin. An initial screening human buccal epithelial cell model and a novel, highly quantitative model using pieces of chicken skin in culture plates were used. Some QAC, particularly cetylpyridinium chlo ride (CPC), were extremely effective at both inhibiting and reversing attachment of viable S. typhinlurium to chicken skin. Pretreatment of chicken skin (room temperature, 10 min) with 0.1% CPC completely inhibited the attachment of S. typhimurium. CPC may be very beneficial in reducing S. typhimurium contamination of poultry carcasses during processing and especially in preventing cross-contamination.     

Factors Affecting Growth and Toxin Production by Clostridium Botulinum Type E on Irradiated (0.3 Mrad) Chicken Skins

A model system (chicken skins with chicken exudate) was used to determine if Clostridium botulinum type E (Beluga) spores, stressed by low dose irradiation, would develop and produce toxin at abuse temperatures of 10 and 30°C in the absence of characteristic spoilage. Unstressed spores germinated, multiplied, and produced toxin on vacuum-packed chicken skins, stored at either 30 or 10°C. Cell numbers increased faster and toxin was evident sooner at 30°C than at 10°C. At 30°C, growth occurred and toxin was produced more slowly when samples were incubated aerobically than anaerobically. When samples were incubated aerobically at 10°C, no toxin was detected within a test period of 14 days. An irradiation dose of 0.3 Mrad at 5°C reduced a spore population on vacuum-sealed chicken skins by about 90%. The surviving population produced toxin at 30°C under either aerobic or anaerobic conditions, at 10°C no toxin was detected even on skins incubated anaerobically. Under the worst conditions (30°C, vacuum packed) toxin was not detected prior to characteristic spoilage caused by the natural flora surviving 0.3 Mrad.     

Effects of High Hydrostatic Pressure on Heat-Resistant and Heat-Sensitive Strains of Salmonella

Salmonella senftenberg 775W, a heat-resistant strain (D_57.5°C= 15.0 min) and Salmonella typhimurium ATCC 7136, a heat-sensitive strain (D_57.5°C=3.0 min), were subjected to hydrostatic pressures of 2,380 to 3,400 atmospheres (atm) at 23°C in phosphate buffer (63 mM, pH 7.0) and chicken medium (strained baby food). Survivor curves showed that cell death occurred in this pressure range and increased as pressure increased. Death was greater in buffer than in the chicken medium. S. senftenberg 775W was more sensitive to pressure than S. typhimurium 7136. Injury occurred over the range of pressures for both species. Recovery at 37°C was possible following pressurization for salmonellae in chicken but not in buffer.     

Reduction of Numbers of Salmonella typhimurium on Poultry Parts by Repeated Freeze-Thaw Treatments

Cells of Salmonella typhimurium suspended in 50 ml of 0.1% buffered peptone were subjected to five cycles of rapid or slow freezing and rapid or slow thawing. A five cycle rapid freeze-rapid thaw process was found to be an effective treatment resulting in 99% reduction in the numbers of S. typhimurium cells. Of the surviving cells after treatment, 75% was sublethally injured. The five cycle rapid freeze-rapid thaw process was investigated for its effectiveness in reducing numbers of S. typhimurium cells on experimentally inoculated chicken wings. The part of chicken wings consisting of ulna and radius with attached skin and muscle was inoculated with low (16–20 CFU/g) or high (ca 1,100 CFU/g) numbers of S. typhimurium and each wing was subjected to five cycles of the rapid freeze-rapid thaw process. There was over 90% reduction in the numbers of S. typhimurium cells on the chicken wings after the freeze-thaw treatment.     

Microbiological Properties of Pork Cheek Meat as Affected by Acetic Acid and Temperature

Our objective was to determine the effect of acetic acid (AA) and temperature in inhibiting Salmonella typhimurium, aerobic plate counts (APCs) and total coliforms on pork cheek meat. Compared with initial APCs of control cheeks, a reduction in log₁₀ CFU/cm² APC by more than 78.6% was found in all samples that were treated with 20 and 40° acetic acid (P < 0.05). Additionally, total coliforms for acidtreated cheeks were lower for both AA treatments (P < 0.05). Cheeks (n = 10/treatment) were also sprayed in a commercial pork slaughter facility carcass wash with 2% AA (25°) and compared to control (non-treated) cheeks. The incidence of Salmonella decreased by 67% for acid-treated cheeks (P < 0.05). A significant decrease in APCs and coliforms occurred for the acid-treated cheeks (P < 0.05).     

ACIDIFIED SODIUM CHLORITE, TRISODIUM PHOSPHATE AND POPULATIONS OF CAMPYLOBACTER JEJUNI ON CHICKEN BREAST SKIN

The present study was designed to determine the effects of acidified sodium chlorite (ASC) and trisodium phosphate (TSP) antimicrobial treatments. Chicken skin samples inoculated with Campylobacter jejuni ATCC 33291 and C. jejuni pc10 (isolated in our laboratory from chicken carcasses) were separately dipped into sterile tap water (control), 0.1% ASC, 10% TSP, 0.1% ASC followed by 10% TSP and 10% TSP followed by 0.1% ASC for 15 s at 25 ± 1C. Campylobacter jejuni counts and pH values were determined after 0, 1, 3 and 5 days of storage at 4 ± 1C. On day 0, reductions were between 1.1–2.5 log for C. jejuni ATCC 33291 and 1.4–2.4 log for C. jejuni pc10, while the reduction effects of all antimicrobials increased (P < 0.001) during the storage period and the bacterial counts reached undetectable levels (<1.0 × 10² cfu/g) on day 5 of storage at 4 ± 1C. The results of this study suggest that introduction of the antimicrobial treatments ASC, TSP and ASC followed by TSP into poultry processing systems could provide an added measure of safety.     

Effects of chlorine dioxide, cetylpyridinium chloride, lactic acid and trisodium phosphate on physical, chemical and sensory properties of ground beef

The impact of beef trimmings treated with either 0.5% cetylpyridinium chloride (CPC), 200-ppm chlorine dioxide (CLO), 2% lactic acid (LA) or 10% trisodium phosphate (TSP) and an untreated control (C) prior to grinding, on instrumental color, sensory characteristics, TBARS values, pH and Lee-Kramer shear under simulated retail display were evaluated. Trimmings were ground, pattied and sampled at 0, 1, 2, 3 and 7 days of display. Patties from LA, CPC and CLO treatments were lighter (L*; P<0.05) and TSP patties were redder (a*; P<0.05) than C. Panelists found TSP and CPC patties were similar or superior in beef and off odor to C on days 3 and 7 of display. Therefore, treatment of beef trimmings before grinding with TSP, CPC, CLO or LA may not only improve ground beef safety, but maintain or enhance patty shelf life.     

ACIDIFIED SODIUM CHLORITE, TRISODIUM PHOSPHATE AND POPULATIONS OF SALMONELLA TYPHIMURIUM AND STAPHYLOCOCCUS AUREUS ON CHICKEN-BREAST SKIN

The present study was designed to determine the individual and combined effects of acidified sodium chlorite (ASC) and trisodium phosphate (TSP) antimicrobial treatments. Chicken‐skin samples inoculated with Salmonella typhimurium and Staphylococcus aureus were separately dipped into sterile tap water, 10% TSP, 0.1% ASC, 0.1% ASC followed by 10% TSP and 10% TSP followed by 0.1% ASC for 15 s at 25C ± 1. On day 0, reductions were 1.4–1.6 log for S. Typhimurium and 1.1–2.1 log for S. aureus, while they were 1.8–2.9 and 0.7–1.7 log, respectively, on day 5 of storage. Results indicated that treatment with ASC solution alone was more effective than treatment with ASC and TSP solutions combined in reducing S. aureus populations on chicken skin during the entire storage period. Similarly, treatment with TSP solution alone was more effective than treatment with ASC and TSP solutions combined in reducing S. typhimurium populations on chicken skin on days 1, 3 and 5 of storage.     

Application of polylactic acid coating with antimicrobials in reduction of Escherichia coli O157:H7 and Salmonella Stanley on apples

Abstract: Survival of Escherichia coli O157:H7 and Salmonella Stanley on apples as affected by application of polylactic acid (PLA) coating with antimicrobials was investigated. Golden Delicious apples were spot inoculated with E. coli O157:H7 or S. Stanley and spray coated with PLA solutions containing lactic acid (LA), disodium ethylenediaminetetraacetic acid (EDTA), sodium benzoate (SB), potassium sorbate (PS), or their combination (LA + EDTA, SB + LA, SB + LA + EDTA). Apples without any coating treatment served as controls. Coating treatments were allowed to dry fully, and the apples were stored at 4 °C for 14 d. Antimicrobial coatings reduced populations of E. coli O157:H7 and S. Stanley by up to 4 log CFU/cm² at 1 d and 4.7 log CFU/cm² at 14 d, compared to controls. SB + LA combination had a similar effectiveness as the SB + LA + EDTA combination against both pathogens and was more effective than other coating treatments. Without antimicrobial treatment, E. coli O157:H7 and S. Stanley were able to survive on apples stored at 4 °C for up to 14 d. The antimicrobial PLA coating provides an alternative intervention to reduce the pathogens on apples. Practical Application: Antimicrobial PLA coatings provide an alternative method to reduce pathogenic contaminations on fruit surface, and therefore, reduce the risk of food‐borne outbreaks.     

Cetylpyridinium chloride direct spray treatments reduce Salmonella on cantaloupe rough surfaces

Cetylpyridinium chloride (CPC) solutions (0, 0.5, or 1.0%) were applied to cantaloupe (“Athena” and “Hale's Best Jumbo” cultivars) rind plugs, either before or after inoculation with a broth culture of Salmonella Michigan (10⁹ CFU/mL) and held at 37°C for 1 or 24 hr. Rind plugs were diluted, shaken, and sonicated, and solutions were enumerated. Texture quality and color were evaluated over 14 days storage at 4°C after 0 and 1% CPC spray applications. A 0.5 or 1.0% (vol/vol) application of CPC after Salmonella reduced the pathogen levels between 2.34 log CFU/mL and 5.16 log CFU/mL in comparison to the control (p < .01). No differences were observed in the firmness and color of 1% CPC treated cantaloupes. Salmonella concentrations on cantaloupes, treated with 1.0% CPC, were lower after 1 hr storage as compared to 24 hr. And, Salmonella on “Athena” surfaces were more susceptible to CPC spray treatments than on “Hale's Best Jumbo.”

Practical applications

Cetylpyridinium chloride (CPC) is the active ingredient of some antiseptic oral mouth rinses, and has a broad antimicrobial spectrum with a rapid bactericidal effect on gram‐positive pathogens. The spray application of CPC solutions to cantaloupe may reduce the level of Salmonella surface contamination during production from irrigation water and manure fertilizers and, during food processing by contaminated equipment and food handlers. Since the surfaces of cantaloupes are highly rough or irregular, bacteria can easily attach to these surfaces and become difficult to remove. Appropriate postharvest washing and sanitizing procedures are needed that can help control Salmonella and other pathogens on melons, especially on cantaloupes with nested surfaces. A direct surface spray application of CPC may be an alternative antimicrobial postharvest treatment to reduce pathogen contamination of cantaloupe melons, while providing an alternative to chlorine‐based solutions.     

Chlorophyll Stability During Continuous Aseptic Processing and Storage

Spinach puree was aseptically processed and packaged at four time-temperature treatments (19.2 and 5.3 sec @ 142°C; 19.2 and 12.2 sec @ 137°C). Samples processed at 142°C for 5.3 sec retained 68% of total chlorophyll compared to blanched samples while all chlorophylls were degraded in retorted product. The rate of chlorophyll b degradation and pheophytin b formation during storage in flexible containers at 4, 25, and 40°C fit a first order kinetic model. Apparent activation energies during storage for each time-temperature treatment ranged between 11.1 and 14.3 kcal/mol. Analyses of degradation products indicated oxidation during storage was not a dominant factor in chlorophyll conversion and color loss.     

Destruction of Salmonella typhimurium on Chicken Wings by Gamma Radiation

No viable CFU of a streptomycin-resistant S. typhimurium were detected on chicken wings inoculated with 100 CFU and treated with 1.8 kGy or greater doses of gamma radiation at 5°C in air. The inoculated S. typhimurium did not recover from radiation injury during 3 days of refrigerated storage. Viable CFU were detected on wings inoculated with 1,000 or 10,000 CFU and irradiated with 1.8 kGy but not on those irradiated with 2.7 or greater kGy. The indigenous aerobic mesophilic population on the wings was reduced from 10⁴ to 44 CFU/cm² by 1.4 kGy.     

Active Packaging of Fresh Chicken Breast,with Allyl Isothiocyanate (AITC) in Combination with Modified Atmosphere Packaging (MAP) to Control the Growth of Pathogens

ABSTRACT: Listeria monocytogenes and Salmonella typhimurium are major bacterial pathogens associated with poultry products. Ally isothiocyanate (AITC), a natural antimicrobial compound, is reportedly effective against these pathogenic organisms. A device was designed for the controlled release of AITC with modified atmosphere packaging (MAP), and then evaluated for its ability to control the growth of L. monocytogenes and S. typhimurium on raw chicken breast during refrigerated storage. In order to obtain controlled release during the test period, a glass vial was filled with AITC and triglyceride. It was then sealed using high-density polyethylene film. The release of AITC was controlled by the concentration (mole fraction) of AITC in the triglyceride and by the AITC vapor permeability through the film. The fresh chicken samples were inoculated with one or the other of the pathogens at 10⁴ CFU/g, and the packages (with and without AITC-controlled release device) were flushed with ambient air or 30% CO₂/70% N₂ before sealing, and then stored at 4 °C for up to 21 d. The maximum reduction in MAP plus AITC (compared to MAP alone) was 0.77 log CFU/g for L. monocytogenes and 1.3 log CFU/g for S. typhimurium. The color of the chicken breast meat was affected by the concentration of AITC. Overall, a release rate of 0.6 μg/h of AITC was found to not affect the color, whereas at 1.2 μg/h of AITC the surface of the chicken was discolored.     

The effect of temperature abuse on Staphylococcus aureus and Salmonellae in raw beef and chicken substrates during frozen storage

Raw beef and chicken substrates inoculated with Staphylococcus aureus and two serotypes of Salmonella were subjected to severe temperature abuse at intervals during six months frozen storage at ?18°C. A method was developed for enumeration of freeze-damaged Salmonellae in a mixed population. After 24 h S. hadar in chicken at c 20 or 27°C, increased by 2·87 and 5·40 log cycles respectively. In beef, S. typhimurium increased by 1·80 and 2·93 log cycles. Refreezing thawed samples reduced the Salmonellae by up to 99%. Growth of St. aureus during thawing was generally slight in comparison but there was little change in viable counts on refreezing. Substantial growth of St. aureus occurred in chicken at 27°C. Some samples were assayed for staphylococcal enterotoxin A but this was not detected in samples containing St. aureus at c 10⁷ cfu.g^?1. Growth of natural saprophytes had caused obvious spoilage by 24 h of thawing.     

EFFECTS OF CETYLPYRIDINIUM CHLORIDE, LACTIC ACID AND SODIUM BENZOATE ON POPULATIONS OF LISTERIA MONOCYTOGENES AND STAPHYLOCOCCUS AUREUS ON BEEF

The effects of cetylpyridinium chloride (CPC), lactic acid (LA) and sodium benzoate (SB) on the Listeria monocytogenes and Staphylococcus aureus populations on beef were evaluated. Samples of longissimus dorsi beef muscle inoculated with L. monocytogenes and S. aureus were dipped into 0.5, 2.0 and 0.3% of CPC, LA and SB, respectively, or an equal mix of any two solutions for 15 s at 35C ± 1. CPC demonstrated 1.93 and 2.15 log reductions of L. monocytogenes and S. aureus, respectively, on the fifth day of refrigerated storage, whereas LA reduced L. monocytogenes and S. aureus by 1.72 and 0.99 log, respectively. Results indicated that the single intervention of CPC and LA solutions were more effective than mixed solutions of these decontaminants to reduce the pathogens of concern on beef.     

Activity of trisodium phosphate compared with sodium hydroxide wash solutions against Listeria monocytogenes attached to chicken skin during refrigerated storage

The potential of using trisodium phosphate (TSP) and sodium hydroxide (NaOH) to reduce Listeria monocytogenes populations in chicken skin was studied. Raw chicken legs inoculated with L. monocytogenes were dipped in water (control), in 8% (pH=12·59), 10% (pH=12·68) and 12% (pH=12·75) (w/v) TSP solutions, or in NaOH solutions of equal pH values to those of TSP: 0·175%, 0·200% and 0·220% (w/v). Surface pH values and L. monocytogenes counts of chicken skin were determined immediately after treatment (day 0) and after 1, 3 and 5 days of storage at 2°C. Compared with water dipping, TSP and NaOH treatments significantly (P<0·05) reduce Listeria populations at days 0, 1, 3 and 5 of refrigerated storage. Bacterial reductions varied between 1·12 and 3·34 log₁₀ cycles for TSP-treated samples and between 1·80 and 3·28 log₁₀ cycles for NaOH treated samples. The observed reductions in all treated samples were significantly (P<0·05) greater following storage. The concentration of the TSP solution was a significant factor in reducing the populations of L. monocytogenes. However, bacterial reductions were similar in samples treated with different concentrations of NaOH. The TSP or NaOH treatments resulted in relatively high residual surface pH values (8–9) initially and throughout storage. The pH values were significantly higher in the samples treated with TSP than in those treated with NaOH.