H7 In Apple Juice Research Articles

Inactivation of Escherichia coli O157:H7 in apple juice via induced electric field (IEF) and its bactericidal mechanism

Non-conventional heating technology based on electric fields can be utilized to process liquid foods. In this study, the induced electric field (IEF) was investigated to clarify its inactivation mechanism on E.coli. Staining results show that inactivation of E.coli by IEF can be attributed to the reversible destruction of the cell membrane, followed by the denaturation of intracellular enzymes, and finally the irreversible rupture of the cell membrane. The increased levels of extracellular proteins and nucleic acids were also observed. IEF treatment at 400 Hz and 800 V (or 53 V/cm) results in a reduction of 4.5 log CFU·mL−1 in the number of E.coli. Storage life analysis shows that IEF treatment can improve the stability of apple juice and the content of bioactive components. Thus, IEF is a potential technique for liquid food processing.

Combined ohmic heating and krypton‐chlorine excilamp treatment for the inactivation of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 in apple juice

AbstractThe combined effect of the 222‐nm krypton‐chlorine (KrCl) excilamp and ohmic heating for the inactivation of Listeria monocytogenes, Salmonella enterica serovar Typhimurium, and Escherichia coli O157:H7 in apple juice was investigated in this study. When ohmic heating and a KrCl excilamp were applied to apple juice simultaneously, the reduction level of E. coli O157:H7 following 70 s (target temperature of 65.9°C) of combination treatment reaching 4.6 log CFU/ml was significantly higher than that of each treatment alone (2.7 log CFU/ml). The same trend, indicating a synergistic bactericidal effect, was observed for L. monocytogenes and S. Typhimurium. Therefore, the combination treatment of the KrCl excilamp and ohmic heating can be used effectively to control bacterial pathogens in apple juice with a reduced processing time.Practical applicationsDemands for energy‐efficient and environmentally friendly bactericidal apparatuses have been increasing. Although the mercury UV lamp has been widely used to inactivate foodborne pathogens in water or juice products individually or combined with heat treatment, the use of this conventional lamp will be limited continuously in accordance with the Minamata Convention treaty, which restricts the use of mercury. Thus, it is of interest to identify the bactericidal effect of an alternative UV‐C lamp and its combination with heat treatment. The synergistic bactericidal effect of the KrCl excilamp and ohmic heating, which are alternative nonthermal and thermal technologies, respectively, was identified in the present study. The results indicated in this study could be utilized by juice processors to achieve a 5‐log reduction in foodborne pathogens.

Application of a Dielectric Barrier Discharge Atmospheric Cold Plasma (Dbd-Acp) for Eshcerichia Coli Inactivation in Apple Juice.

Escherichia coli O157:H7 in apple juice is a potential risk for public health. This study demonstrated that 30 s cold plasma treatment resulted in more than 4 log CFU/mL reduction under 50 W, while the quality attributes of apple juice were not significantly affected. Therefore, cold plasma technology is a promising alternative substitute of traditional thermal processing for juice pasteurization.

Gold decorated polystyrene particles for lateral flow immunodetection of Escherichia coli O157:H7

Conventional lateral flow immunoassays for pathogen detection usually make use of gold nanoparticles to impart the color necessary for a readout. Unfortunately, these immunoassays require an extra-long time enrichment process before the detection. The synthesis of gold-decorated polystyrene particles (Au-PS), and their incorporation in a lateral flow immunoassay (LFIA) with improved sensitivity for detection of the model pathogen Escherichia coli O157:H7 (E. coli O157:H7) were described in this article. The synthesis of the Au-PS particles occurred through the citrate reduction method. Then the particles underwent surface modification through coating with branched polyethylenimine, followed by grafting of the anti-E. coli O157:H7 antibody. The effect of Au-PS particle size and of the surface coverage on the detection limit of the assay was investigated. The Au-PS particles with 0.46 μm PS and 10% Au surface coverage achieved 500 CFU·mL−1 limit of detection (LOD) for E. coli O157:H7 in apple juice, ground beef, and spiked buffer solutions. Furthermore, these particles achieved 100 CFU·mL−1 LOD when the secondary a signal amplification reaction via gold reduction method was used. While the antibody-antigen interaction has a well-known role in detection, a precise optimization of the Au-PS particles used in LFIA assays can significantly affect performance. In our perception, Au nanoparticles coverage on sub-micron sized polystyrene particles was the critical factor that allowed reaching the reported low concentration of E. coli O157:H7 in real food samples.

Use of enhanced nisin derivatives in combination with food-grade oils or citric acid to control Cronobacter sakazakii and Escherichia coli O157:H7

Cronobacter sakazakii and Escherichia coli O157:H7 are well known food-borne pathogens that can cause severe disease. The identification of new alternatives to heating to control these pathogens in foods, while reducing the impact on organoleptic properties and nutritional value, is highly desirable. In this study, nisin and its bioengineered variants, nisin V and nisin S29A, are used alone, or in combination with plant essential oils (thymol, carvacrol and trans-cinnamaldehyde) or citric acid, with a view to controlling C. sakazakii and E. coli O157:H7 in laboratory-based assays and model food systems. The use of nisin variants (30 μM) with low concentrations of thymol (0.015%), carvacrol (0.03%) and trans-cinnamaldehyde (0.035%) resulted in extended lag phases of growth compared to those for corresponding nisin A-essential oil combinations. Furthermore, nisin variants (60 μM) used in combination with carvacrol (0.03%) significantly reduced viable counts of E. coli O157:H7 (3-log) and C. sakazakii (4-log) compared to nisin A-carvacrol treatment. Importantly, this increased effectiveness translated into food. More specifically, sub-inhibitory concentrations of nisin variants and carvacrol caused complete inactivation of E. coli O157:H7 in apple juice within 3 h at room temperature compared to that of the equivalent nisin A combination. Furthermore, combinations of commercial Nisaplin and the food additive citric acid reduced C. sakazakii numbers markedly in infant formula within the same 3 h period. These results highlight the potential benefits of combining nisin and variants thereof with carvacrol and/or citric acid for the inhibition of Gram negative food-borne pathogens.

Radiation resistance and injury in starved Escherichia coli O157:H7 treated with electron-beam irradiation in 0.85% saline and in apple juice.

This study evaluated the influence of starvation on the radiation resistance and injury in Escherichia coli O157:H7, following electron beam irradiation in 0.85% (wt/vol) saline and in apple juice. Washed exponential-phase cells of E. coli O157:H7 that were grown in tryptic soy broth (TSB) at 35°C were starved in 0.85% saline (25°C) for 10 days. Exponential- or stationary-phase cells grown in TSB (35°C) served as controls. Samples of 0.85% saline or pasteurized apple juice, inoculated with control cells or cells starved for 8 days, were exposed to electron beam irradiation at doses ranging from 0.0 (control) to 0.70 kGy. The E. coli survivors were enumerated by plating diluted samples on tryptic soy agar or on Sorbitol McConkey agar and counting bacterial colonies after incubation (35°C) for 24 h. Starved cells consistently exhibited higher irradiation D-values than controls (p<0.05). The D-values for control and starved E. coli O157:H7 in 0.85% saline were 0.11 and 0.26 kGy, respectively; D-values in apple juice were 0.16, 0.19, and 0.33 kGy for exponential, stationary, and starved cells, respectively. Irradiation (0.70 kGy) of E. coli O157:H7 in apple juice reduced numbers of exponential- and stationary-phase cells by ∼4.32 and 3.74 logs, respectively, whereas starved cells were reduced by only 2.20 logs. Exponential-phase cells exhibited the lowest resistance to irradiation, and sublethal injury in survivors of this group was higher than that of stationary-phase or starved cells irradiated at 0.50 or 0.70 kGy (p<0.05). The results of this study indicate that starvation-induced stress cross-protects E. coli O157:H7 from ionizing radiation and should be considered an important factor when determining irradiation D-values for this pathogen.

Inactivation and potential reactivation of pathogenic Escherichia coli O157:H7 in apple juice following ultraviolet light exposure at three monochromatic wavelengths

Ultraviolet (UV) light irradiation at 254 nm is considered as a novel non-thermal method for decontamination of foodborne pathogenic bacteria. However, lower penetration depth of UV light at 254 nm in apple juice resulted in higher UV dose consumption during apple juice decontamination. In addition, no studies are available on the reactivation of pathogens following exposure to UV light in drinks and beverages. Two novel monochromatic UV light sources (λ = 222 and 282 nm) have been developed for bacterial disinfection. However, the inactivation of pathogenic Escherichia coli O157:H7 following exposure to these UV wavelengths is still unclear. Therefore, the present study was conducted to determine the inactivation and reactivation potential of pathogenic E. coli O157:H7 in apple juice following exposure to UV light at three monochromatic wavelengths: Far UV (λ = 222 nm), Far UV+ (λ = 282 nm) and UVC light (λ = 254 nm). The results showed that E. coli O157:H7 is acid-resistant, and up to 99.50% of cells survived in apple juice when incubated at 20 °C for 24 h. Inactivation of E. coli O157:H7 following exposure to Far UV light (2.81 Log reduction) was higher (P < 0.05) than the inactivation caused by UVC light (1.95 Log reduction) and Far UV+ light (1.83 Log reduction) at the similar levels of UV fluence of 75 mJ/cm2. No any reactivation potential was observed for E. coli O157:H7 in dark incubation phases after exposure to UV light as determined by the regular plating method. In addition, the exposure to Far UV light at 222 nm followed by incubating at 37 °C significantly decreased (P < 0.05) the survival of E. coli O157:H7 during dark incubation phase compared to that of UVC and Far UV+ light.

Synergistic combination of essential oils from Morocco and physical treatments for microbial inactivation

This work evaluates the bactericidal effect of essential oils (EOs) of Cyperus longus L., Eucalyptus globulus L., Juniperus phoenicea L., Mentha pulegium L., Rosmarinus officinalis L., and Thymus algeriensis L. from Morocco in combination with mild heat or pulsed electric fields (PEF) against Escherichia coli O157:H7 and Listeria monocytogenes EGD-e suspended in buffer of both pH 7.0 and 4.0, and apple juice. Heat and PEF treatments affected cell envelopes, causing sublethal injuries within survivors as a function of the treatment conditions. Outstanding synergistic lethal effects were shown using mild heat (54 °C, 10 min) or PEF (30 kV/cm, 25 pulses) combined with 0.2 μl/ml of most EOs tested. The combinations of heat and M. pulegium L. or T. algeriensis L. EOs were particularly effective: the time to inactivate 5 log10 cycles of E. coli O157:H7 cells suspended in apple juice was decreased by 3.5 and 5.7 times, respectively, within the range of temperature assayed (54–60 °C). The reduction of the contamination of E. coli O157:H7 in apple juice to 2 × 104 cells/ml allowed us to diminish the addition of M. pulegium L. or T. algeriensis L. EOs from 0.2 to 0.083 and 0.061 μl/ml, respectively, while keeping constant the synergistic effect. The bactericidal effect of EOs improves when combined with mild heat or PEF, especially when pH was acid. Thus, very low doses of EOs need to be proposed. The valuable synergistic effects observed between heat or PEF and a wide variety of EOs offer great potential to improve both traditional heat treatments by reducing treatment intensity and, thus undesirable effects on food quality, and novel PEF treatments by achieving a higher degree of microbial inactivation.

Effects of culture conditions on the subsequent heat inactivation of E. coli O157:H7 in apple juice

Escherichia coli O157:H7 cells were grown in various acidic growth media including an acidogenic nutrient broth (NB) supplemented with 1% glucose (NBG) and NB acidified to pH 4.5 with 0.25% citric or malic acids. The pH in NBG continuously decreased, reaching a final pH of 4.46 after 28 h. The pH in the control culture (NB) did not significantly change throughout the incubation. When heated in apple juice at 55 °C, cells grown in NBG had the significantly highest D55 value (250 ± 39.67 s). Thermal inactivation rates established for cells grown in NB, citric acid- and malic acid-acidified NBs were 51.39 ± 1.34, 25.46 ± 1.21, and 45.42 ± 0.36 s, respectively. When compared with the D55 values of cells previously exposed to combinations of environmental stress factors, cells grown in NBG were also found to be significantly heat resistant and were deemed appropriate to be used in heat challenge studies.

Inactivation of Escherichia coli O157:H7 in apple juice and apple cider by trans-cinnamaldehyde

This study investigated the antimicrobial effect of low concentrations of trans-cinnamaldehyde (TC) on Escherichia coli O157:H7 in apple juice and apple cider. A five-strain mixture of E. coli O157:H7 was inoculated into apple juice or cider at ∼ 6.0 log CFU/ml, followed by the addition of TC (0%v/v, 0.025%v/v, 0.075%v/v and 0.125%v/v). The inoculated apple juice samples were incubated at 23 °C and 4 °C for 21 days, whereas the cider samples were stored only at 4 °C. The pH of apple juice and cider, and E. coli O157:H7 counts were determined on days 0, 1, 3, 5, 7, 14 and 21. TC was effective ( P < 0.05) in inactivating E. coli O157:H7 in apple juice and apple cider. At 23 °C, 0.125 and 0.075%v/v TC completely inactivated E. coli O157:H7 in apple juice (negative by enrichment) on days 1 and 3, respectively. At 4 °C, 0.125 and 0.075%v/v TC decreased the pathogen counts in the juice and cider to undetectable levels on days 3 and 5, respectively. Results indicate that low concentrations of TC could be used as an effective antimicrobial to inactivate E. coli O157:H7 in apple juice and apple cider.

Inactivation of Escherichia coli ATCC 25922 and Escherichia coil O157:H7 in apple juice and apple cider, using pulsed light treatment.

The main objective of this work was to evaluate the effectiveness of pulsed light (PL) treatment for the inactivation of Escherichia coli in liquids with different levels of clarity. Nonpathogenic E. coli ATCC 25922 and pathogenic E. coli O157: H7 were used as challenge organisms. Butterfield's phosphate buffer (BPB), tryptic soy broth (TSB), apple juice, and apple cider were used as substrates. The inoculated liquids were placed in a thin layer (1.3 mm) into glass chambers (23 by 53 by 11 mm) and exposed to PL doses of up to 13.1 J/cm2. PL treatments were performed in a Xenon RS-3000C PL unit, both in static mode and under turbulence. Survivors were determined by standard plate counting or the most-probable-number technique. For static treatments, reduction levels exceeding 8.5 log were obtained in BPB for all strains and reduction levels of about 3.5 log were obtained in TSB. For apple juice, inactivation levels of 2.66 +/- 0.10 log were obtained for E. coli ATCC 25922 and 2.52 +/- 0.19 log for E. coli O157:H7. In cider, inactivation levels of 2.32 +/- 0.16 log and 3.22 +/- 0.29 log were obtained for the nonpathogenic and pathogenic strains, respectively. Inactivation kinetics was characterized using the Weibull model. Turbulent treatments resulted in 5.76 +/- 0.06 log reduction in cider and 7.15 +/- 0.22 log reduction in juice, which satisfies the U.S. Food and Drug Administration requirement of 5-log reduction of E. coli. These results show promise for the use of PL for the effective reduction of E. coli in apple juice and cider.

Evaluation of Escherichia coli O157:H7 in apple juice with Cornus fruit ( Cornus officinalis Sieb. et Zucc.) extract by conventional media and thin agar layer method

Escherichia coli O157:H7 survival in apple juice supplemented with Cornus fruit ( Cornus officinalis Sieb. et Zucc.) extract was studied. Inoculated samples with or without Cornus fruit extract were kept at 21 and 7 °C. Microbial analysis was conducted on days 0, 1, 3, 5, and 7. MacConkey sorbitol agar (MSA), tryptic soy agar (TSA), and thin agar layer (TAL) medium were used to compare the recovery of bacteria stressed under combination treatment. Influence of temperature, storage time, and Cornus fruit on survival of cells was evaluated. The most dramatic reduction of E. coli O157:H7 was observed in apple juice with Cornus fruit extract at 21 °C. At 7 °C, E. coli O157:H7 was reduced by 2.3 log cfu/ml in the apple juice with Cornus fruit extract compared to the control sample on day 7. TAL and TSA were more efficient than MSA. Cornus fruit extract can be used in combination with temperature and storage time controls to inactivate E. coli O157:H7 in apple juice. This study has shown that TAL is a viable method of recovering and differentiating injured microorganisms and apple juice supplemented with Cornus fruit has potential as a value-added beverage with antimicrobial effects and potential health benefits.

SURFACE PLASMON RESONANCE BASED IMMUNOSENSING OF E. COLI O157:H7 IN APPLE JUICE

Escherichia coli O157:H7 was detected in apple juice using an alkanethiol self-assembled monolayer (SAM)based surface plasmon resonance (SPR) immunosensor. Antibodies against E. coli O157:H7 were immobilized on the sensorchip, and apple juice (100%), with no added sugar, was spiked with 105, 106, 107, and 108 CFU/mL of E. coli O157:H7 andinjected over the immobilized antibodies, followed by a pulse of antibodies to complete a sandwich assay. The detection limitand specificity of detection were assessed, and the deterioration of the antibody surface with time was also investigated. Aslow as 106 CFU/mL of E. coli O157:H7 could be detected using the sandwich assay in less than 1 h. The technique couldspecifically detect E. coli O157:H7 in apple juice in the presence of Staphylococcus aureus. This study shows that an SPRimmunosensor has the potential for applications in rapid and label-free detection of pathogens such as E. coli O157:H7 infood.

Antibacterial Effect of Monocaprylin on Escherichia coli O157:H7 in Apple Juice

The antibacterial effect of low concentrations of monocaprylin on Escherichia coli O157:H7 in apple juice was investigated. Apple juice alone (control) or containing 2.5mM (0.055%) or 5mM monocaprylin was inoculated with a five-strain mixture of E. coli O157:H7 at ~6.0 log CFU/ml. The juice samples were stored at 23 or 4°C for 14 or 21 days, respectively, and the population of E. coli O157:H7 was determined on tryptic soy agar plates supplemented with 0.6% yeast extract. At both storage temperatures, the population of E. coli O157:H7 in monocaprylin-supplemented juice samples was significantly lower (P < 0.05) than that in the control samples. The concentration of monocaprylin and the storage temperature had a significant effect on the inactivation of E. coli O157:H7 in apple juice. Monocaprylin at 5mM was significantly more effective than 2.5mM monocaprylin for killing E. coli O157:H7 in apple juice. Inactivation of E. coli O157:H7 by monocaprylin was more pronounced in juice stored at 23°C than in the refrigerated samples. Results of this study indicated that monocaprylin is effective for killing E. coli O157:H7 in apple juice, but detailed sensory studies are needed to determine the organoleptic properties of apple juice containing monocaprylin.

INACTIVATION OF ESCHERICHIA COLI O157:H7 DURING THE STORAGE UNDER REFRIGERATION OF APPLE JUICE TREATED BY PULSED ELECTRIC FIELDS

ABSTRACT The sensitivity of pulsed electric fields (PEF)‐treated E. coli O157:H7 cells to subsequent holding in apple juice has been evaluated. Escherichia coli O157:H7 cells in apple juice were resistant to PEF. A PEF treatment of 400 µs at any electrical field strength was not sufficient to inactivate one log10cycle of cells. However, PEF injured a large proportion of E. coli O157:H7 cells that became sensitive to a subsequent storage under refrigeration in apple juice. The total lethal effect of the combined process depended on the electrical field strength and storage time. The combination of a PEF treatment at 25 kV/cm for 400 µs and a subsequent storage of the apple juice under refrigeration for 48 h allowed five log10cycles of inactivation to be achieved. The combination of PEF and maintenance under refrigeration has been demonstrated to be an effective pasteurization method, by sufficiently reducing the presence of E. coli O157:H7 in apple juice in order to meet U.S. FDA recommendations.

Antimicrobial Activity and Synergistic Effect of Cinnamon with Sodium Benzoate or Potassium Sorbate in ControllingEscherichia coliO157:H7 in Apple Juice

ABSTRACT: Antimicrobial effects of cinnamon, sodium benzoate, potassium sorbate, and combinations were examined against Escherichia coli O157:H7 in apple juice at 8°C and 25°C. E. coli O157:H7 was reduced by 1.6 log colony-forming units (CFU)/mL at 8°C and 2.0 log CFU/mL at 25°C by 0.3% cinnamon. At 8°C, 5.2 log CFU/mL of E. coli O157:H7 was eliminated in 11 d by 0.3% cinnamon with 0.1% sodium benzoate, and in 14 d by 0.3% cinnamon with 0.1% potassium sorbate. At 25°C, 5.3 log CFU/mL E. coli O157:H7 was eliminated in 3 d by the same combinations. A synergistic effect was observed between cinnamon and preservatives against E. coli O157:H7 at 8°C and 25°C.

Inactivation of Salmonella Typhimurium and Escherichia coli O157:H7 in Apple Juice by a Combination of Nisin and Cinnamon

Pasteurized apple juice with nisin (0, 25, 50, 100, and 200 ppm, wt/vol) and cinnamon (0 and 0.3%, wt/vol) was inoculated with Salmonella Typhimurium and Escherichia coli O157:H7 at 104 CFU/ml and stored at 5 and 20°C. Counts on tryptic soy agar (TSA), selective medium (xylose lysine desoxycholate agar for Salmonella Typhimurium, and MacConkey sorbitol agar for E. coli O157:H7), and thin agar layer (TAL) were determined at 1 h and 1, 3, 7, and 14 days. The TAL method (selective medium overlaid with TSA) was used for recovery of sublethally injured cells. The pathogens were gradually inactivated by the acidic pH of apple juice. Nisin and cinnamon greatly contributed to the inactivation. The killing effect was more marked at 20°C, with counts in all treated samples being undetectable by direct plating in 3 days for Salmonella Typhimurium and 7 days for E. coli O157:H7. Thus, several factors influenced the decrease in counts: low pH, addition of nisin and cinnamon, and storage temperature. The TAL method was as effective as TSA in recovering injured cells of the pathogens. The combination of nisin and cinnamon accelerates death of Salmonella Typhimurium and E. coli O157:H7 in apple juice and so enhances the safety of the product.

Rapid detection of respiring Escherichia coli O157:H7 in apple juice, milk, and ground beef by flow cytometry.

Rapid and simple methods to detect viable pathogenic microbes in foods and drinks are required. Flow cytometry was used for the rapid detection of respiring Escherichia coli O157:H7 cells in apple juice, milk, and ground beef. CTC (5-cyano-2,3-ditolyl tetrazolium chloride) was used to estimate the respiratory activity of bacteria. Fluorescein isothiocyanate (FITC)-labeled anti-E. coli O157:H7 direct antibody (FA) was used for the specific detection of target cells. Food samples were inoculated with starved E. coli O157:H7 and E. coli K-12 cells, and analyzed by both fluorescent microscopy and flow cytometry after double staining with FA and CTC. Respiring E. coli O157:H7 cells in food samples showed strong fluorescence of both FA (green) and CTC (red); thus, they could be clearly and specifically distinguished from respiring E. coli K-12 or inactive cells. A good correlation was achieved in flow cytometric analysis between the numbers of inoculated viable E. coli O157:H7 and those detected in milk and apple juice. The detection threshold for this flow cytometry for E. coli O157:H7 in milk, apple juice, and ground beef was 10(3) cells/ml (milk and apple juice) or 10(3) cells/g (ground beef) of sample when the total bacterial number in the sample was 10(6) cells/ml. Respiring E. coli O157:H7 in food samples can be detected specifically within a few hours. Flow cytometry with FA-CTC double staining can be used to examine food contamination with various pathogenic microbes demonstrating physiologic activity through the use of a suitable fluorescent antibody.

The effects of freezing and thawing on the survival of Escherichia coli O157:H7 in apple juice

Unpasteurized apple juice, adjusted to pH 3.6 to 7.0 was inoculated (10 7 CFU/ml) with single strains of E. coli O157:H7 to evaluate the effect of frozen storage on the viability of this organism. Samples were stored under frozen conditions (−20±2°C) for up to 16 days. Cell populations were determined at regular intervals by plating onto tryptic soy agar with added pyruvate (TSAP) or onto sorbitol MacConkey agar (SMA). Populations in the neutralized juice remained unchanged during frozen storage. Populations in non-neutralized juice decreased by 1–3 log 10 CFU/ml depending on the strain tested and the pH of the juice. The greatest population decrease was observed with the first freeze/thaw cycle of frozen storage (24 h) and a slow decline in survival occurred thereafter. Injury was observed after 2 weeks of storage when juice pH was at or below pH 4.2. When samples were subjected to multiple freeze/thaw cycles, loss of viability and injury increased with each freeze/thaw cycle.

Microbial attachment to food and food contact surfaces

The ability of microorganisms to adhere to surfaces has significant implications for food science. Microorganisms attached to plant and animal tissues can affect food safety and spoilage. Microorganisms can adhere firmly and are therefore difficult to remove or inactivate without damaging the underlying tissue. This is not of concern for most processed foods, but it is for foods that are to be sold as raw or minimally processed. Disease outbreaks associated with Salmonella on chicken and fresh produce and Escherichia coli 0157:H7 in apple juice, alfalfa seed sprouts, and lettuce may be related to the inability of sanitizer and washing treatments to remove or inactivate attachedpathogens. Microbial attachment to food contact surfaces is also of significance for food safety and spoilage. Microorganisms attached to processing equipment may escape cleaning and sanitizing procedures and proceed to contaminate processed product. Pathogens originating with raw products can attach to food preparation surfaces, which, if not adequately cleaned before reuse, can serve to recontaminate cooked foods. The ability to attach to and subsequently detach from surfaces is a characteristic of all microorganisms. Attachment is advantageous and perhaps necessary for survival in the natural environment, as it allows microorganisms to exert some control over their nutritional environment, and offers protection from environmental stresses. Attachment is also the initial event in microbial infections, for if a cell fails to adhere it will be carried away from its potential host. Therefore, microbial attachment is a process that has been extensively studied.