Effect of fermentation temperature and must processing on process productivity and product quality in mescal fermentation

We examined the quality and production yield of mescal obtained by fermentation of traditional (including bagasse) and filtered musts at three temperatures (18, 25 and 32 °C). Fermentation temperature did not affect the concentration of methanol, higher alcohols, or dry extracts, and in all cases the product met the standards of the Mexican Official Norm for these compounds. On the other hand, the acidity of the product fell within specifications only for fermentations performed at 18 °C (either must) or 32 °C (filtered must only). Processing at the higher temperature also resulted in increased productivity, demonstrating that fermentation of filtered musts at 32 °C is a useful means of improving both the quality and throughput of mescal production.     

The storage of grape marc: Limiting factor in the quality of the distillate

Grape marc, the mass of skins, stalks and seeds left after the winemaking process, is stored before distillation to produce ethanol by the alcoholic fermentation of the residual sugars. In this work 24 samples of grape marc were stored in four different types of containers. After distillation process, the samples obtained were analyzed by GC–MS to evaluate the influence that the storage exercises on the major volatile composition. Grape marc stored in plastic sacks (1000 kg) produced distillates with low values of the majority volatile compounds, that implies a good quality but a poor aromaticity. Distillates from pomace in plastic drums (250 kg) showed a high content in ethyl esters and higher alcohols, however the concentrations of ethyl acetate and aldehydes and acetal are high too, due to the difficulty to control the aerobic bacteria spoilage. The principal problem of the concrete containers (70,000 kg) is the high methanol production and in the plastic sacks (50 kg) the quick aerobic and anaerobic degradation. With an exhaustive control of oxygen contact, plastic drums and plastic sacks (1000 kg) were the better systems to storage grape marc before distillation.     

Effect of ethanol on the ability of Oenococcus oeni to remove ochratoxin A in synthetic wine-like media

The study focused on the changes in bacterial population, malolactic fermentation and ochratoxin A (OTA) levels in cultures of Oenococcus oeni performed in synthetic medium supplemented with ethanol and OTA. Growth was better in cultures containing 5% ethanol and was not observed in cultures containing 15% ethanol. The OTA removal ability of O. oeni depended on ethanol and initial OTA levels. The highest toxin removal percentage was observed in cultures containing 5% ethanol and 2 μg OTA/l. In ethanol-containing medium part of OTA was not sorbed by O. oeni and remained in the liquid medium. Thus, it cannot efficiently eliminate OTA in acidic ethanol-containing beverages, such as wine. The effect of ethanol on the OTA removal ability of O. oeni is described for the first time.     

Sensor array for the combined analysis of water–sugar–ethanol mixtures in yeast fermentations by ultrasound

For the sugar fermenting industry, it is important to know the exact concentration values of sugar and ethanol in the process fluid during the alcoholic fermentation as an indicator for the fermentation progress. In this study, an ultrasound-based method for determining the concentration of sugar and ethanol simultaneously is presented. The ultrasound velocity in various binary (water–saccharose, water–ethanol) an ternary (water–saccharose–ethanol) mixtures in dependance of the temperature was measured with a pulse-echo method. The sugar and ethanol fraction in aqueous solutions cause an additive, but nonlinear component to the sound velocity of pure water dependant on the concentration and the temperature. A calibration model for the ultrasound velocity in water–sugar–ethanol mixtures was found by establishing a polynomial approach based on the experimental results. The coefficients of this polynom are obtained with a linear regression method by inserting the measurement points. The derived calibration function is continuous, monotone and relates one value of sound velocity to one certain set of concentration values and temperature unambiguously. By means of these mathematical properties, it can be shown that it is possible to determine the sugar and ethanol concentration values in water–sugar–ethanol mixtures only by measurement of the sound velocity at two different temperatures. The method is evaluated by determining the sugar-, respectively ethanol concentration in standardized water–saccharose–ethanol mixtures and in commercial beer probes with an accuracy of approximately 0.5 g/100 g up to 0.01 g/100 g.     

Aflatoxin-producing Aspergillus spp. and aflatoxin levels in stored cassava chips as affected by processing practices

Cassava chips (cassava balls, and cassava pellets) are derived cassava products traditionally produced by farmers in sub-Saharan Africa following fermentation, and drying of fresh roots of cassava, and are widely consumed in Cameroon. Once produced, this food commodity can be stored for more than two months and contaminated by a wide array of harmful microbes. In order to assess persistence of toxigenic fungi in cassava chips, aflatoxin-producing fungi (Aspergillus flavus, Aspergillus nomius, and Aspergillus parasiticus) and aflatoxins were contrasted at regular intervals in home-stored cassava chips collected in two locations of southern Cameroon throughout a two-month monitoring period. Three hundred and forty-six isolates of aflatoxin-producing fungi were found to be associated with all samples. A. flavus contaminated more samples in both types of chips (267 isolates in 53 samples), followed by A. nomius (58 isolates in 15 samples), whereas A. parasiticus was rarest. A direct competitive Enzyme-linked immunosorbent assay (ELISA)-based method was implemented to quantify the content in aflatoxins. Eighteen of the samples contained some aflatoxins at detectable levels whereas 54 did not. The levels of aflatoxin ranged between 5.2 and 14.5 ppb. The distribution of aflatoxin in positive samples depended on 8 parameters including pH, moisture content, storage duration, types of chips, level of contamination by aflatoxin-producing fungi, processing practices and storage facilities. From analysis of variance results, only pH (p < 0.01), duration of storage (p < 0.01), population of aflatoxin-producing species (0.0001) and the chip type (p < 0.05) were significantly related to aflatoxin in positive samples. A stepwise regression analysis (forward selection procedure) indicated that aflatoxin levels were significantly (p < 0.01) correlated with processing practices, storage facilities, and storage duration of the chips.     

Pre-processed bovine milk quality in Trinidad: Prevalence and characteristics of bacterial pathogens and occurrence of antimicrobial residues in milk from collection centres

The study was conducted to assess the impact of the changes in the milk collection system in Trinidad (from twice daily collection to once, introduction of chilling facilities to the collection centres and transportation of milk to the processing plant in insulated truck instead of in metal churns at ambient temperature) on the microbial load and antimicrobial residue quality of the milk as well as the temperature and pH of milk, using standard methods. The presence of antimicrobial residues was detected using the Delvo test kit. Of a total of 266 milk samples from churns, the mean ± sd temperature and log₁₀ ± sd TAPC per ml was 20.36 ± 7.91 °C and 6.3 ± 1.09 respectively. For 20 milk samples from the chillers, the mean temperature and log₁₀ ± sd TAPC per ml was 15.10 ± 2.73 °C and 7.04 ± 0.33 respectively compared with corresponding values for 36 samples collected from the truck, 11.64 ± 4.22 °C and 7.11 ± 0.62 respectively (P < 0.05; X²). The mean TAPC, staphylococcal and E. coli counts per ml of milk from churns were significantly (P < 0.05; X²) higher for milk at low temperature (0–20 °C) compared with milk at high temperature (>30 °C). Eight (4.2%) of 192 milk samples tested contained antimicrobial residues. Of 168 S. aureus isolates tested, 24 (14.3%) were enterotoxigenic while 53 (45.3%) of 117 isolates tested exhibited resistance to various antimicrobial agents while of 386 isolates of E. coli tested, 3 (0.8%) were O157 strain and 129 (64.5%) of 200 isolates exhibited resistance to antimicrobial agents. It was concluded that despite the changes, the microbial load of milk was still high suggesting poor sanitary practices at the farm level. The detection of antimicrobial residues agents coupled with toxigenic S. aureus and E. coli isolates could pose health hazards to consumers.     

Improved control of postharvest decay in Chinese bayberries by a combination treatment of ethanol vapor with hot air

The effect of ethanol vapor treatment (EVT, 250 or 500 μL L^?1 for 3 h) alone or in combination with hot air treatment (HAT, 48 °C for 3 h) on postharvest decay and microbial loads in Chinese bayberries was investigated. Treatment with ethanol vapor or hot air alone both resulted in significantly lower decay incidence caused by Verticicladiella abietina, Penicillium citrinum or Trichoderma viride compared with the control. The combined treatment of 500 μL L^?1 ethanol vapor with hot air showed the lowest incidence of fruit decay caused by these pathogens. This treatment also significantly inhibited spore germination and germ tube elongation of the pathogens in vitro than EVT or HAT alone. Meanwhile, the combined treatment exhibited the lowest natural decay incidence and microbial loads on Chinese bayberries without impairing fruit quality. These results suggest the usefulness of the combined treatment for reducing fruit decay in Chinese bayberries.     

Microflora of traditional starter made from cassava for “attiéké” production in Dabou (Côte d’Ivoire)

Attiéké is a food made from cassava in Côte d’Ivoire by fermentation. The process uses a traditional starter. Studies on 81 starter samples from 3 villages showed that the dominant microflora consists of lactic acid bacteria (5.7 × 10⁷ cfu/g), yeasts (5.5 × 10⁷ cfu/g), Bacillus (3.8 × 10⁷ cfu/g), Enterococcus (3.0 × 10⁶ cfu/g), total coliforms (3.0 × 10⁶ cfu/g), thermotolerant coliforms (8.0 × 10³ cfu/g) and mould (2.0 × 10⁶ cfu/g). Lactic acid bacteria, Bacillus spp, yeasts, faecal Enterococci and moulds are organisms which could play a role in the cassava fermentation. Coliforms may indicate contamination from the environment during production.     

Chemical composition of fermented milk (roub and mish) in Sudan

Two batches of whole milk, skim milk and yoghurt that used for processing of roub and mish from Khartoum Dairy Company (Butana factory) were analyzed. Similarly roub and mish (fermented milk), obtained from the same samples, were also collected and analyzed during this study. Similarly, a total of four experiments as an attempt to process “Roub and mish” in the factory’s laboratory were tried following the same procedures of the factory for two batches. While in the other two pasteurization for whole milk were done before manufacturing. Comparison of chemical constituents (total solids %, total proteins %, fat %, lactose %, ash %, and acidity), and pH were estimated in those products.The total solids %, the total proteins % and the fat % recorded lower means for the control samples, compared to those of the factory for whole milk; yoghurt; mixture; and roub. However, the control samples for mish revealed a higher mean than those produce commercially by the factory. Moreover, the higher values obtained for ash and acidity for skim milk and fermented products, in the control samples, reflected the adulteration done at the factory. Similarly, Lactose revealed higher means for whole milk; skim milk; and mixture for the control samples. While yoghurt; roub; and mish showed a higher mean values for the factory samples. This might be due to the fermentation action by the bacteria.The results indicated that there were significance differences in total solids %, ash %, and lactose % (P ⩽ 0.05) between the different groups. Similarly there is significant increase in pH, fat % (P ⩽  0.001) and acidity (P ⩽ 0.01) between the different groups. However, a non-significance difference was found for the other measurements.When comparing roub and mish a non significant differences were obtained for the measurements. Between mixture and roub significance variations were reported for ash %, lactic acid % (P ⩽ 0.05) and lactose (P  ⩽ 0.001). Also, significance variations were found in ash % (P  ⩽ 0.05), and lactose % (P ⩽ 0.001), when comparing mixture and mish. This could be due to fermentation and addition of spices.     

Essential oils to control Alternaria alternata in vitro and in vivo

The inhibitory effects of five essential oils (thyme, sage, nutmeg, eucaptus and cassia) against Alternaria alternata were tested at different concentrations (100–500 ppm) in vitro. The cassia oil and thyme oil both exhibited antifungal activity against A. alternata. The cassia oil inhibited completely the growth of A. alternata at 300–500 ppm. The thyme oil exhibited a lower degree of inhibition 62.0% at 500 ppm. Spore germination and germ tube elongation of the pathogens in potato dextrose broth was strongly inhibited in the presence of 500 ppm cassia oil. Irreversible inhibition of fungal growth could be caused by exposure to 300 ppm and 400 ppm cassia oil for 6 days and 500 ppm cassia oil for 3 days. Cassia oil at 500 ppm reduced the percentage of decayed tomatoes. The experiments on reducing natural decay development of tomatoes gave similar results. Therefore, essential oils could be an alternative to chemicals for control of postharvest phytopathogenic fungi on fruits or vegetables.     

Antimicrobial effect of acidified sodium chlorite,sodium chlorite,sodium hypochlorite,and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro

Fresh-cut cilantro is particularly susceptible to microbial growth and, therefore, use of an effective sanitizer on this product is of great importance. The objective of this study was to evaluate the efficacy of different sanitizing treatments on reducing Escherichia coli O157:H7 populations, aerobic mesophilic bacterial, yeast and mould counts on fresh-cut cilantro. Cut cilantro was treated with sodium hypochlorite (SH) at 0.2 g L^?1 free chlorine and acidified sodium chlorite (ASC) at 0.1, 0.25, 0.5 and 1 g L^?1, along with the components of ASC, i.e., citric acid (CA) at 6 g L^?1 and sodium chlorite (SC) at 1 g L^?1. In the present study, it was found that SH inactivated, at maximum, 1–1.3 log cfu g^?1 of background or pathogenic microflora present on cut cilantro. However, reductions of more than 3 log cfu g^?1 were observed after washing with 1 g L^?1 of ASC. Moreover, when lower concentrations of ASC were used (0.25 and 0.5 g L^?1), microbial populations were reduced by about 2 log cfu g^?1. SC was as effective as ASC at 1 g L^?1 in reducing aerobic mesophilic bacteria and E. coli O157:H7 populations, although it was not as effective as ASC in reducing yeast and mould populations.     

Catalytic performance of organically templated nano nickel incorporated-rice husk silica in hydroconversion of cyclohexene and dehydrogenation of ethanol

Rice husk silica (RHS) was extracted from local rice husk by acid digestion and burning at 650 °C. RHS-Ni catalyst was prepared by dissolving RHS in 1 N NaOH and titrating with 3 N HNO₃ containing 10 wt.% Ni²⁺. The organic modifiers, either p-amino benzoic acid (A) or p-phenylenediamine (PDA) were incorporated in 5 wt.% and reduced in H₂ flow. Investigation of the three catalysts, (RHS-Ni)_R350, (RHS-Ni–A)_R350 and (RHS-Ni–PDA)_R350, confirmed good dispersion of Ni nanoparticles; all catalysts were amorphous. The BET surface areas increased in the order: (RHS-Ni)_R350 < (RHS-Ni–A)_R350 < (RHS-Ni–PDA)_R350 with controlled pore sizes. The as-prepared catalysts were applied for both hydroconversion of cyclohexene with molecular H₂ and ethanol dehydrogenation, using a flow-type reactor, at different temperatures. The activity in cyclohexene hydroconversion and selectivity to cyclohexane depended upon the reaction temperature; at t < 150 °C, the increased hydrogenation activity was referred to the formed SiO₂–Ni–amine complex, pore regulation as a prime requirement for H₂ storage and homogeneous distribution of incorporated Ni nanoparticles. At t > 150 °C, the backward dehydrogenation pathway was more favored, due to unavailability of H₂; the process became structure-sensitive. In ethanol conversion, the prevailing dehydrogenation activity of organically modified catalyst samples was encouraged by improved homogeneous distribution of Ni nanoparticles and created micropre system.     

Antimicrobial resistance of Campylobacter spp. isolated from broilers in small poultry processing operations in Trinidad

The study determined the frequency of resistance of Campylobacter spp. isolated from broilers in small processing operations in 6 health divisions of Trinidad using the disc diffusion method. Of 319 isolates of Campylobacter jejuni tested, 312 (97.8%) exhibited resistance to one or more of the six antimicrobial agents used compared with 176 (97.2%) of 181 isolates of C. coli. The frequency of resistance amongst isolates was statistically significantly (P < 0.05, χ²) different across health divisions. Overall, the resistance was highest to sulfamethoxazole/trimetoprim (SXT) (87.0%) and ciprofloxacin (86.6%) and lowest to gentamicin (5.4%) and the differences were statistically significant (P < 0.05, χ²). The relatively high resistance to SXT and ciprofloxacin was not unexpected since both antimicrobial agents are routinely used in the poultry industry in Trinidad and Tobago but may pose therapeutic problems in broiler-borne gastroenteritis in humans.     

Superheated steam reduction of deoxynivalenol in naturally contaminated wheat kernels

Contamination of wheat with the Fusarium mycotoxin deoxynivalenol (DON) is a concern to the ethanol industry as it is stable during most processing operations and will be concentrated in the spent grains, which are potentially a valuable feedstock. Superheated steam at four processing temperatures (110, 135, 160, and 185 °C), three steam velocities (0.65, 1.3, and 1.5 m/s), and processing times of 2–15 min were used to treat wheat kernels naturally contaminated with DON to find the best processing parameters for the reduction of DON. A commercial enzyme-linked immunosorbent assay (ELISA) kit was used to determine DON levels in the wheat samples. Samples became increasingly toasted, displaying a brown color with increasing processing temperatures and times, and became friable after processing at temperatures of 160 and 185 °C. Only samples processed at 185 °C and 1.3 m/s exhibited any starch gelatinization. Significant (P < 0.05) reductions in DON levels were seen at 160 and 185 °C but were not generally seen at 110 and 135 °C and the effect of velocity was not significant (P > 0.05). Reductions of up to 52% were achieved at 185 °C and 6 min processing time and were due only to thermal degradation and not to solubilization and extraction.     

Microbiological quality of legume-based traditional fermented foods marketed in West Bengal,India

A total of 105 samples of six different types of legume-based popular fermented foods, namely amriti, dhokla, dosa, idli, papad and wadi, purchased from retail outlets in West Bengal, was analysed to determine their microbiological safety status. While dhokla and idli were of high-moisture foods (62 g (100 g)⁻¹), others had a lower moisture level (14–27 g (100 g)⁻¹). Papad was alkaline (pH 8.7), whereas all the other foods were acidic (pH 4.4–5.8). Every sample was found contaminated with total aerobic mesophilic bacteria (detection limit, 10 cfu g⁻¹); 38% (40/105) of the samples contained more than 10⁶ cfu g⁻¹. Aerobic mesophilic bacterial spores were found in 88% (92/105) of the samples (detection limit, 100 cfu g⁻¹), whereas their anaerobic counterparts were present in 39% (41/105) of the samples (detection limit, 10 cfu g⁻¹). Although all the samples, excepting one, were free from Staphylococcus aureus (detection limit, 100 cfu g⁻¹), 20% (21/105) of the samples were found contaminated with Bacillus cereus (detection limit, 100 cfu g⁻¹). Enterobacteriaceae were found in 46% (48/105) of the samples (detection limit, 10 cfu g⁻¹). Of the Enterobacteriaceae isolates, 92% were coliforms and 57% were faecal coliforms. Escherichia coli (detection limit, 10 cfu g⁻¹) was found in only one sample each of wadi and idli, at a load of 10³–10⁴ g⁻¹. Salmonella (detection limit, 1 cell (25 g)⁻¹) occurred in 12 samples of wadi, idli and papad, however was absent in the other three products. Clostridium perfringens (detection limit, 10 cfu g⁻¹) and Shigella (detection limit, 1 cell (25 g)⁻¹) could not be detected. The results obtained in the present study indicated that these foods were manufactured using poor-quality starting materials, processed under unhygienic conditions, or/and temperature-abused during transportation and storage. Based on these results, a guideline is recommended for obtaining safe products.     

Thermally treated wine retains antibacterial effects to food-born pathogens

Although cooking with wine and consumption of wine as a warm beverage is widespread, antibacterial effects of thermally treated wine have not been studied.We examined in vitro antibacterial activity of wine heated at 75 and 125 °C for 45 min against Salmonella enterica serovar Enteritidis and Escherichia coli. Their effects were compared with intact red wine, dealcoholized wine (DW) and dealcoholized wine reconstituted (RDW) with water to the initial volume. Samples were also analysed for their phenolics content, antioxidant capacity, resveratrol and ethanol content and pH.Total phenolics concentration and related antioxidative activity followed changes in samples volume, regardless of treatment type, while pH of all samples remained stable and ranged from 3.09 to 3.24.The order of the antibacterial activity of wine samples was: intact wine > heated at 75 °C > heated at 125 °C > DW > RDW.Antibacterial activity of the samples could not be related to their content of resveratrol as a single phenolics compound, antioxidative capacity or pH.Thermally treated wine under conditions applicable to food processing in everyday life, may be effective antibacterials in spite of significant heat-induced changes in their physical–chemical composition.     

Microbial profile of buffalo sausage during processing and storage

A study was made on the microbial levels of buffalo sausage during preparation and storage at 4 ± 1 °C. Microbial counts in raw minced meat were, total plate count (TPC) (log cfu/g) 5.41 ± 0.25; coliforms (MPN/g) 23.2; Staphylococcus aureus (log cfu/g) 1.57 ± 0.11; yeasts and molds (log cfu/g) 2.29 ± 0.07 and lactic acid bacteria (LAB) (log cfu/g) 0.60 ± 0.20. Sausage emulsion showed similar trend in microbial counts with minimal microbial contamination during the preparation of emulsion. Cooked buffalo sausage gave the following microbial counts: TPC (log cfu/g) 3.75 ± 0.31; coliforms (MPN/g) 0.2; LAB (log cfu/g) 0.07 ± 0.01; yeast and molds (log cfu/g) 0.72 ± 0.07. S. aureus, Clostridium perfringens and Bacillus cereus were not detected in cooked sausages. These results indicate that steam cooking for 45 min followed in the study was effective in reducing the microbial counts substantially. The investigation revealed that shelf life of cooked buffalo sausage was 31 days in either vacuum or CO₂ at 4 ± 1 °C. The results indicated that spoilage of vacuum packed cooked buffalo sausage was likely due to LAB while microflora other than LAB may be responsible for spoilage of CO₂ packed cooked buffalo sausage. The study suggests that measures such as low initial microbial counts, hygienic precautions during preparation of sausage, steam cooking for 45 min, vacuum or CO₂ packing and storage at 4 ± 1 °C would control the microbial growth and provide wholesomeness and safety to the buffalo sausage.     

Partial characterization of bacteriocin AMA-K,produced by Lactobacillus plantarum AMA-K isolated from naturally fermented milk from Zimbabwe

Strain AMA-K, isolated from naturally fermented milk produced in Gwanda, Kafusi area, Zimbabwe, was identified as Lactobacillus plantarum based on sugar fermentation reactions (API 50 CHL) and PCR with species-specific primers. The cell-free supernatant containing bacteriocin AMA-K inhibited the growth of Listeria innocua and Enterococcus faecalis. Based on tricine–SDS–PAGE, bacteriocin AMA-K is 2.9 kDa in size. Activity levels of 12 800 AU/ml was recorded in MRS broth at 30 °C and 37 °C. Complete inactivation or significant reduction in bacteriocin activity was observed after treatment with proteolytic enzymes, but not with catalase and α-amylase. Bacteriocin activity was not destroyed after treatment with SDS, Tween 20, Tween 80, urea, triton X-100 or EDTA. Loss of activity was recorded after treatment with Triton X-114. Bacteriocin AMA-K remained stable after 2 h of incubation at pH 2.0–12.0 and at 100 °C, respectively. The bacteriocin not adheres to the surface of the producer cell and has a bacteriolytic mode of action. Bacteriocin production is stimulated by the presence of Listeria innocua. Lactobacillus plantarum AMA-K grows in milk, but produces only 800 AU bacteriocin per ml after 24 h.     

Determination of ethyl carbamate in cider spirits by HPLC-FLD

An analytical method based on HPLC-FLD with prior derivatization with 9-xanthydrol for the determination of ethyl carbamate (EC) in cider spirits is reported. The parameters usually examined in the method validation were evaluated. Good linearity was obtained with a correlation coefficient exceeding 0.9999, the limits of detection and quantitation being 1.64 and 3.56 μg/L, respectively. Recoveries ranged between 94% and 98%, while the precision of the method was <5% (RSD). The method was used to determine EC in samples from different origins with the aim of completing the characterization of cider spirits. Values obtained were usual for this type of drink, ranging between the lower limit of quantitation and 67 μg/L.     

Prevalence of virulence genes in Escherichia coli isolated from food in Casablanca (Morocco)

This study was undertaken to determine the frequency of potentially pathogenic Escherichia coli (E. coli) strains among E. coli isolated from Casablanca, Morocco. The E. coli strains were isolated from ground beef (n = 140), turkey (n = 200), sausage (n = 120), seafood (n = 60), domestic water (n = 35) and well water (n = 50). The prevalence of E. coli was 48%, 45%, 35.5%, 30%, 8.3%, 0%, for well water, ground beef, turkey, sausage, sea food and domestic water, respectively. Two hundreds E. coli isolates were tested for the presence of 17 virulence genes associated with strains causing intestinal and extra-intestinal infections. The virulence genes included stx1, stx2, lt, st, hlyA, aggA, saa, astA, iucD, cnf1, eaeA, bfpA, ial, ipaH, afa, pap and sfa. PCR showed that 37% (74) of E. coli isolates carried one or more of these virulence genes. No virulence genes were found in E. coli strains isolated from sea food samples. In contrast, 10% of the ground beef samples, 18% of the turkey samples, 17.5% of sausage samples and 6% of well water contained specific factors for intestinal E. coli pathogens.