High hydrostatic pressure inactivation of total aerobic bacteria, lactic acid bacteria, yeasts in sour Chinese cabbage

Guacamole is an avocado sauce highly appreciated for its pleasant taste and nutritional value. The present study addressed the impact of high-hydrostatic pressure (HP) treatments on the product safety and bacterial diversity. Four HP treatments, 5 min each, were applied: (A) 450 megapascals (MPa) at 22 °C; (B) 450 MPa at 50 °C; (C) 600 MPa at 22 °C; (D) 600 MPa at 50 °C. Controls and treated samples were refrigerated stored for 50 days. The residual surviving fraction was lowest for the 600 MPa treatment at 50 °C. Bacterial growth on media supplemented with antibiotics (cefotaxime and imipenem) or the biocide benzalkonium chloride was detected only from control samples but not from HP-treated samples. High throughput sequencing analysis indicated that the bacterial diversity of control samples was dominated by members of Fam. Enterobacteriaceae, but it changed to a lactic acid microbiota during storage. HP-treated samples showed reduced relative abundances of Enterobacteriaceae and lactic acid bacteria and higher abundances of Pantoea, Ralstonia and Methylobacterium. Results from the study indicate that HP treatments of guacamole at 50 °C show higher microbial inactivation compared to 22 °C. However, all treatments reduced the levels of Enterobacteriaceae and penem-tolerant bacteria and provided product stability against acidification by lactic acid bacteria.

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Efficacy of Nisin against Staphylococcus aureus in Experimentally Contaminated Sucuk, a Turkish-Type Fermented Sausage

Journal of Food Protection ◽

10.4315/0362-028x-72.8.1739 ◽

2009 ◽

Vol 72 (8) ◽

pp. 1739-1743 ◽

Cited By ~ 10

Author(s):

HAMPARSUN HAMPIKYAN

Keyword(s):

Staphylococcus Aureus ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Water Activity ◽

Aerobic Bacteria ◽

Fermented Sausage ◽

Subsequent Storage

Sucuk is a fermented sausage widely consumed in Turkey. The ability of different concentrations of nisin to inhibit Staphylococcus aureus in artificially contaminated sucuk was examined. Sucuk dough was prepared, inoculated with S. aureus ATCC 25923 at a level of 106 CFU/g, and then divided into six equal portions to which different concentrations of nisin (0, 25, 50, 100, 150, 200 μg/g) were added. Microbiological (S. aureus, total mesophilic aerobic bacteria, and lactic acid bacteria) and physicochemical (pH, water activity, and moisture) analyses were conducted initially and after 1, 3, 5, 10, 15, 20, 25, 30, 35, and 45 days. S. aureus populations decreased to below detectable limits in sucuk containing 200 or 150 μg of nisin per g after 30 and 35 days of storage, respectively, whereas S. aureus populations in 45-day-old sucuk containing 0, 25, 50, and 100 μg of nisin per g were 5.36, 5.68, 4.10, and 3.54 log CFU/g, respectively. Hence, the addition of nisin at 150 μg/g or greater to sucuk dough can be used to prevent the growth of S. aureus in sucuk during fermentation and subsequent storage.

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Tokat Bez Sucuğunun Mikrobiyolojik Kalitesinin İncelenmesi

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v8i12.2683-2694.3878 ◽

2020 ◽

Vol 8 (12) ◽

pp. 2683-2694

Author(s):

Nesrin Kaval ◽

Nilgün Öncül ◽

Zeliha Yıldırım

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Fecal Coliform ◽

Microbiological Quality ◽

Total Coliform ◽

Aerobic Bacteria ◽

Escherichia Coli O157 ◽

Salmonella Spp ◽

Microbiological Parameters

In this study, the microbiological quality of traditionally produced Bez Sucuk in Tokat and its vicinity was investigated. For this purpose, 30 Bez Sucuk samples obtained from butchers, producers of Bez Sucuk, were analyzed for total count of mesophilic aerobic bacteria, lactic acid bacteria, yeasts-moulds, total coliform, fecal coliform, Staphylococcus aureus, Bacillus cereus, and Cl. perfringens. Also, the presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp. were investigated in all samples. pH and water activity of the samples were determined. As the result of the analysis, the counts of the microbiological parameters investigated were found as follows: total mesophilic aerobic bacteria 3.5×106-4.23×109 CFU/g, lactic acid bacteria 5.55×105-2.45×109 CFU/g, yeasts and moulds 2.50×103-6.90×109 CFU/g, total coliform

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Comparison of High Hydrostatic Pressure, Ultrasound, and Heat Treatments on the Quality of Strawberry–Apple–Lemon Juice Blend

Foods ◽

10.3390/foods9020218 ◽

2020 ◽

Vol 9 (2) ◽

pp. 218 ◽

Cited By ~ 2

Author(s):

Xiaoping Feng ◽

Zhongyu Zhou ◽

Xiaoqiong Wang ◽

Xiufang Bi ◽

Yuan Ma ◽

...

Keyword(s):

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Lemon Juice ◽

Aerobic Bacteria ◽

Most Probable Number ◽

Total Phenols ◽

Probable Number ◽

The Us ◽

Total Anthocyanins

Changes in the microbial, physicochemical, and sensory properties of blended strawberry–apple–lemon juice were investigated to comparatively assess the influence of three processing treatments, namely high hydrostatic pressure (HHP) (500 MPa/15 min/20 °C), ultrasound (US) (376 W/10 min/35 °C), and heat treatment (HT) (86 °C/1 min) over 12 days of storage at 4 °C. The results showed that the total aerobic bacteria (TAB) counts in the HHP-, US-, and HT-treated juice blends were less than 2 log10 CFU/mL, the yeast and mold (Y & M) counts were less than 1.3 log10 CFU/mL, and the coliforms most probable number (MPN/100 mL) was less than 3 after 10 days at 4 °C. Anthocyanins were maintained by HHP, but decreased by 16% and 12% after US and HT, respectively. Total phenols increased by 18% and 7% after HHP and US, respectively, while they were maintained by the HT. Furthermore, better maintenance of total phenols, total anthocyanins, ascorbic acid, antioxidant capacity, color, and sensory values were observed in the HHP-treated juice blend stored for 10 days at 4 °C, compared to both the US- and HT-treated samples. Therefore, HHP was proposed to be a better processing technology for juice blend.

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Evaluation of the Hygienic Quality of Raw Cow’s Milk in Oujda City Morocco

Biosciences Biotechnology Research Asia ◽

10.13005/bbra/2482 ◽

2017 ◽

Vol 14 (2) ◽

pp. 587-591

Author(s):

K. Mchiouer ◽

S. Bennani ◽

N. Sh. El-Gendy ◽

M. Meziane

Keyword(s):

Staphylococcus Aureus ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Fecal Coliform ◽

Raw Milk ◽

Total Coliform ◽

Aerobic Bacteria ◽

Milk Samples ◽

Fecal Streptococci

ABSTRACT: The aim of this study is to determine the microbiological quality of raw cows’ milk of Oujda city. Raw milk samples are collected randomly between June 2014 and May 2015 from 20 Mahlaba (dairies) for microbiological evaluation. The samples are analyzed to determine total mesophilic aerobic bacteria (TMAB), total coliform, fecal coliform, staphylococcus aureus, fecal streptococci, proteolytic bacteria and lactic acid bacteria. The results of bacterial count showed that there is a variation between all the milk samples and a period effect is also observed. The mean counts of total mesophilic aerobic bacteria from all sale points are between 1.76×106 and 40.17×106 CFU/ml. Milk samples reveled counts total coliform and fecal coliform ranging from 0.58×105 to 11.10×105 CFU/ml and from 0.60×103 to 14.64×103 CFU/ml, respectively. Staphylococcus aureus are also detected in all samples with counts ranging from 0.35 ×103 to 3.08×103 CFU/ml. Fecal streptococci are found in all milk samples, at counts ranging from 0.16 ×102 to 2.18 ×102 CFU/ml. And finally, proteolytic and lactic acid bacteria are between 0.3×103 and 2.86×103 CFU/ml and 2.37×106 and 24.14 ×106 CFU/ml respectively. These results indicate a lack of compliance with good manufacturing practice at milking, collection and transportation of raw milk.

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Combined Effect of Natural Essential Oils, Modified Atmosphere Packaging, and Gamma Radiation on the Microbial Growth on Ground Beef

Journal of Food Protection ◽

10.4315/0362-028x-71.6.1237 ◽

2008 ◽

Vol 71 (6) ◽

pp. 1237-1243 ◽

Cited By ~ 28

Author(s):

M. TURGIS ◽

J. HAN ◽

J. BORSA ◽

M. LACROIX

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Essential Oils ◽

Shelf Life ◽

Pathogenic Bacteria ◽

Combined Treatment ◽

Modified Atmosphere Packaging ◽

Ground Beef ◽

Aerobic Bacteria ◽

Modified Atmosphere

Selected Chinese cinnamon, Spanish oregano, and mustard essential oils (EOs) were used in combination with irradiation to evaluate their ability to eliminate pathogenic bacteria and extend the shelf life of medium-fat-content ground beef (23% fat). Shelf life was defined as the time when the total bacterial count reached 107 CFU/g. The shelf life of ground beef was determined for 28 days at 4°C after treatment with EOs. The concentrations of EOs were predetermined such that sensory properties of cooked meat were maintained: 0.025% Spanish oregano, 0.025% Chinese cinnamon, and 0.075% mustard. Ground beef samples containing EOs were then packaged under air or a modified atmosphere and irradiated at 1.5 kGy. Ground beef samples (10 g) were taken during the storage period for enumeration of total mesophilic aerobic bacteria, Escherichia coli, Salmonella, total coliforms, lactic acid bacteria, and Pseudomonas. Mustard EO was the most efficient for reducing the total mesophilic aerobic bacteria and eliminating pathogenic bacteria. Irradiation alone completely inhibited the growth of total mesophilic aerobic and pathogenic bacteria. The combination of irradiation and EOs was better for reducing lactic acid bacteria (mustard and cinnamon EOs) and Pseudomonas (oregano and mustard EOs). The best combined treatment for extending the shelf life of ground beef for up to 28 days was EO plus irradiation (1.5 kGy) and modified atmosphere packaging.

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