Reduction in Spoilage Microbiota and Cyclopiazonic Acid Mycotoxin with Chestnut Extract Enriched Chitosan Packaging: Stability of Inoculated Gouda Cheese

Active chitosan-based films, blended with fibrous chestnut (Castanea sativa Mill.) tannin-rich extract were used to pack Gouda cheese that has been contaminated with spoilage microflora Pseudomonas fluorescens, Escherichia coli, and fungi Penicillium commune. A comprehensive experimental plan including active chitosan-based films with (i) chestnut extract (CE), (ii) tannic acid (TA), and (iii) without additives was applied to evaluate the film′s effect on induced microbiological spoilage reduction and chemical indices of commercial Gouda cheese during 37 days while stored at 4 °C and 25 °C, respectively. The cheese underwent microbiology analysis and chemical assessments of ultra-high-performance liquid chromatography (UHPLC) (cyclopiazonic acid), pH, and moisture content. The biopackaging used for packing cheese was characterized by mechanical properties before food packaging and analyzed with the same chemical analysis. The cheese microbiology showed that the bacterial counts were most efficiently decreased by the film without additives. However, active films with CE and TA were more effective as they did not break down around the cheese and showed protective properties against mycotoxin, moisture loss, and pH changes. Films themselves, when next to high-fat content food, changed their pH to less acidic, acted as absorbers, and degraded without plant-derived additives.

Characterization of the temperature fluctuation effect on shelf life of an octopus semi-preserved product

The aim of this work is to study the effect of temperature fluctuations on spoilage microbial flora behaviour of a semi-preserved seafood product in modified atmosphere packaging (MAP) as well as to find correct interpretation criteria for simulating temperature fluctuations during storage tests. The study concerned 54 packages of “Octopus carpaccio” that were grouped in three batches and stored at 3 different temperature profiles: the first (16 packages - Group 4°C) was stored at 4±0.5°C; the second (16 packages - Group 8°C) was stored at 8±0.5°C; the third (16 packages - Group F) was stored under a fluctuating temperature regime between 2°C and 14°C. Spoilage microflora, pH and AW has been monitored, at regular intervals, along the storage period (44 days). A predictive model was constructed according to the accredited scientific literature and validated against the observed growth curves of the above three groups. Afterwards, the predictive model has been used setting the temperature at the mean value of fluctuations (6.72°C), at the kinetic mean value of fluctuations (7.80°C) and at the 75th percentile value of fluctuations (11.14°C). The best fitting to the observed data was obtained with the kinetic mean temperature value and this result shows that this parameter can be proposed to reproduce the temperature fluctuation along the distribution and the domestic storage when a storage test has to be carried out.

Microbial Ecology of Decontaminated and Not Decontaminated Beef Carcasses

The objective of this study was to investigate spoilage microflora of decontaminated and not decontaminated beef carcasses. Carcasses after skinning and after chilling at two beef plants (A, a small plant where no interventions but dry chilling are used; B, a large plant where multiple antimicrobial interventions and spray chilling are used) were swab-sampled for determination of carcass microflora. The numbers of aerobes, Pseudomonas, Brochothrix thermosphacta, lactic acid bacteria (LAB), and Enterobacteriaceae (EB) on carcasses at plant A after skinning were 5.2, 3.7, 2.8, 3.9, and 1.6 log cfu 15,000 cm-2 and they were not significantly different (p>0.05) from those on carcasses at plant B at equivalent times. The numbers of EB were significantly lower (p<0.05) on carcasses after chilling at both plants. However, no difference was observed for the other four groups of microorganisms (p>0.05). At plant A, the microflora on carcasses after skinning and after chilling included 18 and 19 bacterial species, with Psychrobacter (30.9%) and Psychrobacter (42.9%) being the respective predominant genus, respectively. At plant B, the microflora after skinning and after chilling included 21 and 17 bacterial species, with Chryseobacterium (18.6%), Kocuria (18.6%) and Brevibacterium (18.6%), and Pseudomonas (33.3%) being the respective predominant genera. The spoilage microflora of decontaminated beef carcasses is similar in numbers to that of conventionally produced carcasses, suggesting the decontamination treatments for beef carcasses may not cause major difference in storage life of chilled vacuum packaged beef, the major form of beef for international and domestic trading in North America.

First ever report on the antimicrobial activities of some selected mangrove halophytes of Sundarban against milk spoilage microflora

The study was governed by the objective of investigating the antimicrobial effects of mangrove leaf extracts. The fresh and dried leaf extracts from Avicennia marina (Forssk.) Vierh., Avicennia officinalis L., Aegiceras corniculatum (L.) Blanco, Aegialitis rotundifolia Roxb., Acanthus ilicifolius L, Lumnitzera racemosa Willd., Excoecaria agallocha L. and Sonneratia apetala Buch-Ham. were found to have inhibitory effects on the milk spoilage microflora obtained from curd sample. Methanol and Acetone were used as extraction solvents and in comparison, extracts by acetone were observed to suppress the microbial growth to lesser extents. Leaf extracts of A. marina, A. officinalis L. racemosa and A. rotundifolia were able to exert relatively greater inhibitory effect on the milk spoilage microbial broth than others, although all the species expressed some degree of suppression. Interestingly A. rotundifolia, S. apetala, L. racemosa and E. agallocha demonstrated greater efficiency in formation of larger growth inhibition zones on the petri plates. The extracts obtained from dry leaves produced greater adverse effects of the microbes than the raw leaf extracts. The data generated were analyzed with the help of 'ANOVA: Single factor' and 'F-test: Two sample for variance' and data sets were of statistical significance at 0.05 level of significance as null hypothesis was rejected.

Inhibition of Listeria monocytogenes by Buffered Dry Vinegar in Reduced-Sodium Ready-to-Eat Uncured Turkey Stored at 4°C

ABSTRACT A reduced-sodium ready-to-eat (RTE) uncured turkey was manufactured with buffered dry vinegar treatments to validate the inhibition of Listeria monocytogenes and spoilage microflora and to determine the effects on sensory and quality attributes. Samples were stored at 4°C for 12 weeks, and the study was independently replicated three times. Two different five-strain inocula of L. monocytogenes obtained from different sources were used for evaluating the efficacy of the buffered dry vinegar treatments. The results showed that 0.6 and 0.8% buffered dry vinegar with a sodium base (BDV-SB) and buffered dry vinegar with a potassium base (BDV-PB) at 0.7 and 0.9% controlled L. monocytogenes for 12 weeks. The untreated control product containing no buffered dry vinegar showed &gt;1 log increase in L. monocytogenes populations counts at the end of 2 weeks. Statistical analysis confirmed that the dry vinegar treatments inhibited (P &lt; 0.05) the growth of L. monocytogenes compared with the untreated control. No significant differences (P &gt; 0.05) were seen in the inhibition of L. monocytogenes between the two different five-strain inocula. Instrumental color results showed no significant differences between the treatments. Purge loss results showed no significant differences between the dry vinegar treatments, but significant differences were seen between the untreated control and dry vinegar treatments at a few testing intervals. The overall results indicated that the dry vinegar ingredients (6.66 to 8.83 mM acetic acid in the finished product) were effective in inhibiting L. monocytogenes obtained from multiple sources in reduced-sodium RTE uncured turkey stored at 4°C without adversely impacting the quality attributes.

Unusual Compositions of Microflora of Vacuum-Packaged Beef Primal Cuts of Very Long Storage Life

Vacuum-packaged top butt cuts from a beef packing plant that does not use any carcass decontaminating interventions were assessed for their organoleptic and microbiological properties during storage at 2 or −1.5°C. Cuts stored at 2°C were acceptable after storage for 140 days but were unacceptable after 160 days because of persistent sour, acid odors. Odors of cuts stored at −1.5°C for 160 days were acceptable. The numbers of aerobes on cuts increased from &lt;1 log CFU/cm2 to 7 or 6 log CFU/cm2 for cuts stored at 2 or −1.5°C, respectively. The numbers of Enterobacteriaceae increased from &lt; −1 log CFU/cm2 to 5 or 3 log CFU/cm2 for cuts stored at 2 or −1.5°C, respectively. Bacteria recovered from initial microflora were, mainly, strictly aerobic organisms. Bacteria recovered from cuts stored for 160 days were mainly Carnobacterium spp. that grew on an acetate-containing agar generally selective for lactic acid bacteria other than Carnobacterium. C. divergens and C. maltaromaticum were recovered from cuts stored at 2°C, but C. maltaromaticum was the only species of Carnobacterium recovered from cuts stored at −1.5°C. No lactic acid bacteria of genera that usually predominate in the spoilage microflora of vacuum-packaged beef at late storage times were recovered from the spoilage microflora. The findings indicate that carnobacteria, initially present at very small numbers, grew exponentially to persistently dominate the spoilage microflora of vacuum-packaged beef cuts of unusually long storage life.

Efficacy of Various Antimicrobials on Reduction of Salmonella and Campylobacter and Quality Attributes of Ground Chicken Obtained from Poultry Parts Treated in a Postchill Decontamination Tank

Ground chicken is likely to have higher microbiological loads than whole carcasses and parts. Therefore, it is necessary to identify antimicrobials that reduce pathogens and overall microbial loads without negatively impacting meat quality. The objectives of this research were to evaluate the effect of various postchill antimicrobials on reducing Salmonella and Campylobacter, and determine the impact of these treatments on shelf life and quality attributes of ground chicken. Five treatments (0.003% chlorine, 0.07 and 0.1% peracetic acid [PAA], and 0.35 and 0.6%cetylpyridinium chloride [CPC]) were evaluated. Samples (n = 120) of skin-on chicken breast and thigh meat were inoculated with Salmonella Typhimurium (108 CFU/ml) and C. jejuni (108 CFU/ml). Following a 30-min attachment time, parts were rinsed with either chlorine, PAA, or CPC in a decontamination tank for 23 s. Parts then were ground, samples (25 g) were plated, and reduction of Salmonella Typhimurium and C. jejuni was determined. Noninoculated ground breast and thigh meat were used for sensory and shelf-life determination. Samples (n = 200) for shelf-life determination were collected on days 1, 4, 7, and 10 to estimate spoilage microflora of ground chicken stored at 4°C. Additionally, color measurement and sensory evaluation were conducted on days 1, 4, and 7. Ground chicken treated with 0.07 and 0.1% PAA had the greatest reductions (P ≤ 0.05) in Salmonella and Campylobacter providing approximately a 1.5-log reduction, followed by a 0.8-log reduction after treatment with 0.35 and 0.6% CPC. Chlorine (0.003%) was the least effective treatment (P ≤ 0.05), while treatments with 0.07 and 0.1%PAA also extended the shelf life of ground chicken for 3 days. None of the treatments had negative impact on color or sensory attributes of ground chicken patties during the storage (P ≤ 0.05). Results from this study indicated that using PAA as an antimicrobial agent in a postchill decontamination tank to treat ground poultry parts is effective for the reduction of Salmonella and Campylobacter while maintaining product quality.

Use of Antimicrobial Films and Edible Coatings Incorporating Chemical and Biological Preservatives to Control Growth ofListeria monocytogeneson Cold Smoked Salmon

The relatively high incidence ofListeria monocytogenesin cold smoked salmon (CSS) is of concern as it is a refrigerated processed food of extended durability (REPFED). The objectives of this study were to compare and optimize the antimicrobial effectiveness of films and coatings incorporating nisin (Nis) and sodium lactate (SL), sodium diacetate (SD), potassium sorbate (PS), and/or sodium benzoate (SB) in binary or ternary combinations on CSS. Surface treatments incorporating Nis (25000 IU/mL) in combination with PS (0.3%) and SB (0.1%) had the highest inhibitory activity, reducing the population ofL. monocytogenesby a maximum of 3.3 log CFU/cm2(films) and 2.9 log CFU/cm2(coatings) relative to control samples after 10 days of storage at 21°C. During refrigerated storage, coatings were more effective in inhibiting growth ofL. monocytogenesthan their film counterparts. Cellulose-based coatings incorporating Nis, PS, and SB reduced the population ofL. monocytogenes, and anaerobic and aerobic spoilage flora by a maximum of 4.2, 4.8, and 4.9 log CFU/cm2, respectively, after 4 weeks of refrigerated storage. This study highlights the effectiveness of cellulose-based edible coatings incorporating generally regarded as safe (GRAS) natural and chemical antimicrobials to inhibit the development ofL. monocytogenesand spoilage microflora thus enhancing the safety and quality of CSS.