Application of oil-in-water nanoemulsions based on grape and cinnamon essential oils for shelf-life extension of chilled flathead mullet fillets.

BACKGROUND: The effect of nanoemulsions prepared with grape seed and cinnamon essential oils on the shelf-life of flathead mullet (Mugil cephalus) fillets was evaluated by determining physicochemical (pH, free fatty acids, peroxide value, total volatile base nitrogen (TVB-N), and thiobarbituric acid reactive substances (TBARs)), sensory and microbiological (mesophilic aerobic bacteria, total psychrophilic bacteria, and Enterobacteriaceae counts) properties during 14 day storage at 2 °C. RESULTS: The nanoemulsions showed good stability and low average droplet size. The results indicated that nanoemulsion treatments significantly prolonged the shelf-life of the fillets. Treatment inhibited increases in pH and TVB-N, and retarded lipid oxidation and hydrolysis. Sensory assessment revealed that treatment induced shelf-life extension from 10 to 14 days, compared with controls. Microbiological analyses showed nanoemulsion treatment caused shelf-life extension from 10 to 12 days with reduction of microbiological contamination by up to 1 log cfu g-1 in mesophilic and 1.5 log cfu g-1 in psychrotrophic bacteria. CONCLUSION: Considering the results, grape seed and cinnamon essential oil nanoemulsions could be considered as novel antimicrobial and antioxidant materials for shelf-life extension of flathead mullet fillets during cold storage. © 2021 Society of Chemical Industry.

Anti-Escherichia coli O157:H7 as Natural Preservative to Control and Prevent Food Contamination in Meat and Fish Products.

BACKGROUND AND OBJECTIVE: Shiga toxin-producing Escherichia coli O157:H7 is a troubled foodborne pathogen associated with contamination of meat, fish and poultry. The present work aimed to evaluate plant extracts as natural preservatives anti- Escherichia coli O157:H7 in meat and fish products. MATERIALS AND METHODS: Antibacterial activity and minimum inhibitory concentrations (MICs) of seven herbal plants, clove, marjoram, sage, pomegranate peel, turmeric, Cassia fistula and black pepper and their different 6 mixes were examined against Escherichia coli O157:H7. Phytochemical qualitative analysis, phenolic compounds (HPLC), total phenolic, total flavonoid contents and antioxidant activities of individual extracts and their 6 mixes were evaluated. Combination Mix 5 extract was applied on meat and fish-fillet, then its antimicrobial effect against E. coli O157:H7 and sensory evaluation were assessed. RESULTS: Five extracts exhibited good antibacterial activity against Escherichia coli O157:H7. The greatest inhibition zone was recorded by clove aqueous extract (25 mm). Mix 5 (clove, sage, pomegranate and Cassia fistula) showed the highest inhibition with MIC of 3.0 mg mL-1. This mix exhibited strong anti-bactericidal effect against E. coli O157:H7 in meat and fish-fillet products throughout 8 days of cold storage (4°C). The sensory evaluation revealed that Mix 5 was acceptable by panelists with concentration of 0.50% in beef burgers and 0.25% in fish-fillet. CONCLUSION: This study suggests that the use of herbal extracts provide antibacterial potentials against food pathogens in meat and fish products.

Chitosan and Oregano Oil Treatments, Individually or in Combination, Used To Increase the Shelf Life of Vacuum-Packaged, Refrigerated European Eel (Anguilla anguilla) Fillets.

We investigated the impact of chitosan and oregano essential oil (EO) individually or in combination on the quality of eel fillets in vacuum packaging (VP) and stored under refrigeration (4°C). Treatments studied were (i) control eel fillets stored in VP (E), (ii) eel fillets treated with 0.3% (v/w) oregano EO and stored in VP (E-OR), (iii) eel fillets treated with 2.0% (w/v) chitosan and stored in VP (E-CH), and (iv) eel fillets treated with 2.0% (w/v) chitosan and 0.3% (v/w) oregano EO and stored in VP (E-CH-OR). Treatments E-CH-OR and E-CH significantly reduced counts of mesophilic bacteria, Pseudomonas, Shewanella, and yeasts and molds during storage. Use of chitosan alone or in combination with oregano EO led to a significant reduction in concentrations of trimethylamine nitrogen and total volatile basic nitrogen in fillets, which led to lower concentrations of thiobarbituric acid reactive substances compared with the control samples. The eel samples in the E-CH and E-CH-OR groups were sensorially acceptable during the entire refrigerated storage period of 18 days. Presence of chitosan in the E-CH and E-CH-OR fillets did not negatively affect the taste of the fillets. E-CH fillets received a higher taste score than did E-CH-OR fillets probably because of the distinct and "spicy" lemon taste of chitosan, which was well received by the sensory panel. Based on overall sensory data (based on mean sensory scores of odor and taste), the shelf life was 6 days for the control fillets, 10 days for the E-OR fillets, and >18 days for the E-CH and E-CH-OR fillets stored in VP at 4°C. Overall, chitosan-treated eel fillets had lower microbial loads and a longer shelf life compared with the controls. Chitosan-treated eel fillets were preferred over oregano-treated fillets. Chitosan alone or in combination with oregano could be used as a preservative treatment and shelf-life extender for other seafoods.

Olive leaf extracts for shelf life extension of salmon burgers.

In this work, the effect of the addition of olive leaf extracts on the quality of vacuum-packed salmon burgers stored at 4 ℃ during 16 days has been studied. Olive leaf extract and its hydrolysate were initially characterized and then incorporated to salmon burgers. A shelf life study was conducted in three different batches (control, olive leaf extract, and hydrolyzed olive leaf extract burgers). Among the chemical indices determined, total volatile base nitrogen values were lower in hydrolyzed olive leaf extract and olive leaf extract burgers than in control samples. Lipid oxidation was lower in salmon burger with olive leaf extract. Salmon mince treated with hydrolyzed olive leaf extract showed lower microbial counts during the whole study, which extended the shelf life of the fish product. Therefore, the potential of olive leaf extracts to preserve salmon burgers during cold storage has been demonstrated.

Modulation of fatty acid composition and growth in Sporosarcina species in response to temperatures and exogenous branched-chain amino acids.

Psychrotolerant endospore-forming Sporosarcina species have been predominantly isolated from minced fish meat (surimi), which is stored under refrigeration after heat treatment. To develop a better method for preserving surimi-based food products, we studied the growth and fatty acid compositions of the isolated strain S92h as well as Sporosarcina koreensis and Sporosarcina aquimarina at cold and moderate temperatures. The growth rates of strain S92h and S. koreensis were the fastest and slowest at cold temperatures, respectively, although these strains grew at a similar rate at moderate temperatures. In all three strains, the proportions of anteiso-C15:0 and unsaturated fatty acids (UFAs) were significantly higher at cold temperatures than at moderate temperatures. Furthermore, supplementation with valine, leucine, and isoleucine resulted in proportional increases in iso-C16:0, iso-C15:0, and anteiso-C15:0, respectively, among the fatty acid compositions of these strains. The proportions of the UFAs were also altered by the supplementation. At cold temperatures, the growth rates of strain S92h and S. koreensis, but not of S. aquimarina, were affected by supplementation with leucine. Supplementation with isoleucine enhanced the growth of S. koreensis at cold temperatures but not that of the other strains. Valine did not affect the growth of any strain. These results indicate that anteiso-C15:0 and UFAs both play important roles in the cold tolerance of the genus Sporosarcina and that these bacteria modulate their fatty acid compositions in response to the growth environment.

Inhibitory Effects of Spices on Biogenic Amine Accumulation during Fish Sauce Fermentation.

The presence of high levels of biogenic amines is detrimental to the quality and safety of fish sauce. This study investigated the effects of ethanol extracts of spices, including garlic, ginger, cinnamon, and star anise extracts, in reducing the accumulation of biogenic amines during fish sauce fermentation. The concentrations of biogenic amines, which include histamine, putrescine, tyramine, and spermidine, all increased during fish sauce fermentation. When compared with the samples without spices, the garlic and star anise extracts significantly reduced these increases. The greatest inhibitory effect was observed for the garlic ethanolic extracts. When compared with controls, the histamine, putrescine, tyramine, and spermidine contents and the overall biogenic amine levels of the garlic extract-treated samples were reduced by 30.49%, 17.65%, 26.03%, 37.20%, and 27.17%, respectively. The garlic, cinnamon, and star anise extracts showed significant inhibitory effects on aerobic bacteria counts. Furthermore, the garlic and star anise extracts showed antimicrobial activity against amine producers. These findings may be helpful for enhancing the safety of fish sauce.

Tannins and extracts of fruit byproducts: antibacterial activity against foodborne bacteria and antioxidant capacity.

The shelf life of fresh fish and meat transported over long distances could be extended by using plant-based extracts to control spoilage bacteria. The goals of the present study were to identify plant-based extracts that effectively suppress the main spoilage bacteria of chilled fish and lamb and to assess their antioxidant capacity. The phenolic compounds in wood-based tannins and extracts isolated from byproducts of the fruit processing industry were identified and/or quantified. The total phenol content, but not the flavonoid to total phenol ratio, was strongly associated with higher antibacterial activity against several fish and lamb spoilage bacteria in zone of inhibition and minimum inhibitory concentration assays as well as greater antioxidant capacity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical assay. The most promising compounds in both cases, and thus good candidates for antibacterial packaging or antioxidant dietary supplements, were mango seed extract and tannic acid containing mostly polygalloyl glucose type phenols.

Antimicrobial activity of Chinese bayberry extract for the preservation of surimi.

BACKGROUND: Chemical preservatives such as sodium nitrite and potassium sorbate have been widely used to keep surimi products fresh. However, the potential harmfulness to human health cannot be ignored. This study was conducted to develop natural preservatives for the storage of Collichthys surimi. RESULTS: Among the eight Chinese traditional herbs and fruits, Chinese bayberry extract showed the greatest inhibitory effect against surimi spoilage bacteria Serratia marcescens and Pseudomonas aeruginosa. Moreover, N-butanol phase extract of bayberry (NB) showed the greatest activity among the different phases of bayberry extract. When Chinese bayberry extract was combined with tea polyphenol, an additive inhibitory effect was observed on growth of Hansenula anomala, Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Our results further indicated that the shelf life of surimi products stored at room temperature can be extended when supplemented with Chinese bayberry extract. CONCLUSION: Our results suggest that Chinese bayberry extract can be used as a natural preservative for the storage of Collichthys surimi.

Quality changes during storage of minced fish products containing dietary fiber and fortified with ω3 fatty acids.

Two ready-to-eat minced fish products from hake were developed, their proximate composition and fatty acid profiles determined and their quality changes followed during 3.5 months under refrigeration at 2 ± 1 °C and 10 ± 1 °C. These products contain dietary fiber and are innovative and healthy. The formulation was identical, except vegetable oil (VO), 5.6% (w/w) in one group and 2.7% (w/w) plus 2.9% (w/w) cod liver oil (CLO) in the other. CLO products had a higher ω3/ω6 ratio (0.54 ± 0.02 versus 0.08 ± 0.02) and ensured, per 100 g serving, the 500 mg recommended daily intake of eicosapentaenoic and docosahexaenoic acids. CLO products showed lower gel strength (p ≤ 0.05), however, other textural properties were similar to those of the VO group. Thiobarbituric acid reactive substances values were higher in CLO products. All groups presented acceptable sensory scores and no microbiological growth. During storage products became redder and less yellow, while seafood aroma and flavor declined and saltiness perception augmented. Temperature had a negative effect on sensory elasticity and instrumental texture.

Combined effect of MAP and active compounds on fresh blue fish burger.

The combined effects of three essential oils [thymol, lemon extract and grapefruit seed extract (GFSE)] and modified atmosphere packaging conditions (MAP) on quality retention of blue fish burgers was studied and discussed. In particular, samples were packaged in air and in three different gas mix compositions: 30:40:30 O(2):CO(2):N(2), 50:50 O(2):CO(2) and 5:95 O(2):CO(2). During a 28-day storage period at 4 degrees C, the nutritional, microbiological and sensorial quality of the packed products was assessed. The potential development of biogenic amines was also evaluated. The obtained results highlight the possibility to improve the microbial quality of blue fish burgers by using very small amount of thymol (110ppm), GFSE (100ppm) and lemon extract (120ppm) in combination with MAP. Based primarily on microbiological results, the combined use of the tested natural preservatives and a packaging system characterized by a high CO(2)-concentration, was able to guarantee the microbial acceptability of fish burgers until the 28th day of storage at 4 degrees C. On the other hand, results from sensory analyses showed that sensorial quality was the sub-index that limited the burgers shelf life (to about 22-23days), even if the proposed strategy was also effective in minimizing the sensory quality loss of the product having no effect on its nutritional quality.

Survival and growth of Salmonella and Vibrio in som-fak, a Thai low-salt garlic containing fermented fish product.

Fermentation of raw fish is a common process in Asia for improvement of shelf life and safety, however, little is known about the survival of pathogenic bacteria in these products. Raw fish may be contaminated with Salmonella and Vibrio species. The purpose of this study was to determine survival and potential growth of Salmonella enterica serovar Weltevreden, S. enterica serovar Enteritidis, Vibrio cholerae and V. parahaemolyticus as influenced by the preservation parameters (sodium chloride, garlic and lactic acid) present in the Thai fermented fish product som-fak. The inhibitory effects of sodium chloride (0-4%), garlic (0-10%) and lactic acid (pH levels as in som-fak) were measured in modified brain heart infusion (BHI) broth at 30 degrees C. All bacteria were inhibited by 8-10% sodium chloride. Salmonella grew in all concentrations of garlic whereas Vibrio spp. were inhibited by 1.0-1.5%. Lactic acid was inhibitory at levels above 1.5%. The combinations of sodium chloride, lactic acid and garlic showed a distinct hurdle effect in the broth system. Neither S. Enteritidis, V. cholerae nor V. parahaemolyticus grew in garlic (0.5-1%), regardless of the level of sodium chloride (0.5-4% (w/v)), when lactic acid (0.5-2%) was present. S. Weltevreden was the least inhibited of the four bacteria and grew in the combination of 0.5% garlic and 0.5% lactic acid regardless of the NaCl level (0.5-4% (w/v)). Som-fak with 0 to 10% garlic or 2% glucose was inoculated with either (i) 10(3) CFU/g Salmonella Weltevreden, (ii) 10(6) CFU/g garlic fermenting Lactobacillus plantarum strain 509 or (iii) a combination of the two strains and stored at 30 degrees C. The Salmonella count increased to >10(8) CFU/g (>10(6) CFU/g for 10% garlic) in all types of som-fak inoculated with S. Weltevreden within the first day. Only a combination of at least 6% garlic and L. plantarum 509 was enough to prevent growth of the inoculated Salmonella whereas adding the Lactobacillus strain alone or in combination with glucose was insufficient to prevent growth. Our results show that Salmonella Weltevreden can grow in som-fak independently of the inhibitory substances normally present in this type of product, emphasising the importance of preventing contamination. However, our results also suggest that the use of garlic fermenting starter cultures in combination with garlic could improve safety of fermented fish products.

Antioxidant activities of purple rice bran extract and its effect on the quality of low-NaCl, phosphate-free patties made from channel catfish (Ictalurus punctatus) belly flap meat.

Purple rice bran contains high amounts of natural antioxidants that consist of water- and lipid-soluble compounds. Hexane-insoluble and hexane-soluble fractions were separated from 100% methanolic extract from purple rice bran (RBE-HI and RBE-HS, respectively). Total anthocyanin, tannin, flavonoid, and phenolics contents were determined in those fractions, and their antioxidant capacities were evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capability, oxygen radical absorbance capacity (ORAC), and iron chelating capability (ICC). RBE-HI and RBE-HS were also added to restructured patties made from minced channel catfish (Ictalurus punctatus) belly flap meat. Lipid oxidation, color, and/or textural properties were determined for raw and cooked patties during a 12-d storage at 4 degrees C. All antioxidant indices, except for ICC, of RBE-HI were significantly higher than those of RBE-HS due probably to its higher anthocyanin content (P < 0.05). RBE-HS showed higher ICC (P < 0.05). However, both fractions showed similar antioxidant activity in raw and cooked patties during storage, resulting from the complexity of antioxidant action in food systems. Textural properties (hardness, cohesiveness, chewiness, and springiness) in cooked patties with RBE-HS and RBE-HI were well maintained during storage, but changed significantly in the control (P < 0.05). Only RBE-HS limited microbial growth in raw patties during storage (P < 0.05), but its inhibitory effect was marginal because of low-dose and physical interactions with the matrix. L* (lightness) and a* (redness) of raw and cooked patties decreased significantly by both fractions, whereas b* (yellowness) was significantly decreased by RBE-HI and increased by RBE-HS (P < 0.05). In conclusion, we suggest that purple rice bran extract is applicable to meat products as a natural preservative, but color change in the products may limit its application.

Study on the synergic effect of natural compounds on the microbial quality decay of packed fish hamburger.

The effectiveness of natural compounds in slowing down the microbial quality decay of refrigerated fish hamburger is addressed in this study. In particular, the control of the microbiological spoilage by combined use of three antimicrobials, and the determination of their optimal composition to extend the fish hamburger Microbiological Stability Limit (MAL) are the main objectives of this work. Thymol, grapefruit seed extract (GFSE) and lemon extract were tested for monitoring the cell growth of the main fish spoilage microorganisms (Pseudomonas fluorescens, Photobacterium phosphoreum and Shewanella putrefaciens), inoculated in fish hamburgers, and the growth of mesophilic and psychrotrophic bacteria. A Central Composite Design (CCD) was developed to highlight a possible synergic effect of the above natural compounds. Results showed an increase in the MAL value for hamburgers mixed with the antimicrobial compounds, compared to the control sample. The optimal antimicrobial compound composition, which corresponds to the maximal MAL value determined in this study, is: 110 mgL(-1) of thymol, 100 mgL(-1) of GFSE and 120 mgL(-1) of lemon extract. The presence of the natural compounds delay the sensorial quality decay without compromising the flavor of the fish hamburgers.

Some quality aspects of fish patties prepared from an Indian major carp, Labeo rohita (Ham.).

Six different types of fish patties were prepared from de-boned meat of three weight groups (250 500 g, 501-750 g, and 751-1,000 g) of an Indian major carp, Labeo rohita, using two extenders (boiled potato and corn flour). The weight of the fish and the type of the extender affected the nutritional quality of the patties. Cooking lowered the crude protein but increased the total lipid, total soluble sugars, and contents of the patties. Cooking yield increased with an increase in the weight of the fish. Similarly, the use of corn flour as the extender resulted in a higher cooking yield and higher fat retention capacity than boiled potato. The type of extender had no effect on the water-holding capacity of the patties. The weight of the fish and the extender had no significant effect on appearance, colour, flavour, taste, and the overall acceptability of the product. However, the patties prepared from 250-500 g and 501-750 g weight groups with corn flour as the extender had a significantly higher score for their texture. The total plate count suggested that the patties were safe (from microbiological point of view) up to a storage period of 80 days.

Purification and characterisation of an extracellular fructan beta-fructosidase from a Lactobacillus pentosus strain isolated from fermented fish.

Lactobacillus pentosus B235, which was isolated as part of the dominant microflora from a garlic containing fermented fish product, was grown in a chemically defined medium with inulin as the sole carbohydrate source. An extracellular fructan beta-fructosidase was purified to homogeneity from the bacterial supernatant by ultrafiltration, anion exchange chromatography and hydrophobic interaction chromatography. The molecular weight of the enzyme was estimated to be approximately 126 kDa by gel filtration and by SDS-PAGE. The purified enzyme had the highest activity for levan (a beta(2-->6)-linked fructan), but also hydrolysed garlic extract, (a beta(2-->1)-linked fructan with beta(2-->6)-linked fructosyl sidechains), 1,1,1-kestose, 1,1-kestose, 1-kestose, inulin (beta(2-->1)-linked fructans) and sucrose at 60, 45, 39, 12, 9 and 3%, respectively, of the activity observed for levan. Melezitose, raffinose and stachyose were not hydrolysed by the enzyme. The fructan beta-fructosidase was inhibited by p-chloromercuribenzoate, EDTA, Fe2+, Cu2+, Zn2+ and Co2+, whereas Mn2+ and Cu2+ had no effect. The sequence of the first 20 N-terminal amino acids was: Ala-Thr-Ser-Ala-Ser-Ser-Ser-Gln-Ile-Ser-Gln-Asn-Asn-Thr-Gln-Thr-Ser-Asp-Val-Val. The enzyme had temperature and pH optima at 25 degrees C and 5.5, respectively. At concentrations of up to 12% NaCl no adverse effect on the enzyme activity was observed.

Genotypic and phenotypic characterization of garlic-fermenting lactic acid bacteria isolated from som-fak, a Thai low-salt fermented fish product.

AIMS: To evaluate the importance of garlic for fermentation of a Thai fish product, and to differentiate among garlic-/inulin-fermenting lactic acid bacteria (LAB) at strain level. METHODS AND RESULTS: Som-fak was prepared by fermentation of a mixture of fish, salt, rice, sucrose and garlic. pH decreased to 4.5 in 2 days, but omitting garlic resulted in a lack of acidification. LAB were predominant and approximately one third of 234 isolated strains fermented garlic and inulin (the carbohydrate reserve in garlic). These strains were identified as Lactobacillus pentosus and Lact. plantarum. Randomly Amplified Polymorphic DNA (RAPD) analysis revealed one major RAPD type (29 strains) isolated from all stages of fermentation. CONCLUSION: Garlic was essential for acidification of som-fak and garlic-fermenting strains constituted a significant, homogeneous part of the LAB flora. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study indicates the role of fructans (garlic/inulin) as carbohydrate sources for LAB. Fructan fermenters may have several biotechnological applications, for example, as probiotics.

Exopolysaccharide-producing lactic acid bacteria strains from traditional Thai fermented foods: isolation, identification and exopolysaccharide characterization.

Lactic Acid Bacteria (LAB) isolated from various traditional Thai fermented foods were screened for exopolysaccharides (EPS) production. From 104 isolates, two rod-shaped and five coccal-shaped LAB were able to produce EPS from sucrose on solid media. However, only the cocci were capable of producing EPS in liquid media and these were identified as Pediococcus pentosaceus. Pediococcus pentosaceus strains AP-1 and AP-3 produced EPS in high yield. In liquid media containing sucrose as carbon source, the amount of EPS produced by AP-1 and AP-3 strains was 6.0 and 2.5 g/L, respectively. The isolated and purified EPSs were chemically characterized. On the basis of sugar composition, methylation analysis and nuclear magnetic resonance spectroscopy, both the EPSs were shown to belong to the same dextran class. In particular, both EPSs differed from linear dextran by branching through 3,6-di-Osubstituted alpha-D-glucopyranosyl residues. The EPS from P. pentosaceus AP-3 was characterized by a relatively higher degree of branching and by a higher molecular weight than that from P. pentosaceus AP-1.

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation.

Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.

Styrene formation by the decomposition by Pichia carsonii of trans-cinnamic acid added to a ground fish product.

It is not well known how the formation of styrene by microorganisms can occur in foods. In this study, we described and characterized the production of styrene by a yeast isolated from chikuwa fish paste. The styrene was not detected in fresh and normal food products nor in the food package's plastic film. The food containing styrene contained cinnamic acid as an antimicrobial agent and spice, and it was contaminated by 5.4 x 10(6) CFU of a yeast per gram. On the basis of morphological and biochemical features, the yeast isolated was determined to be a strain of Pichia carsonii, now designated strain CHI. Strain CHI, which was able to grow on cinnamic acid, had the ability to form styrene from trans-cinnamic acid via trans-p-coumaric and caffeic acids. The MIC of trans-cinnamic acid against strain CHI was 230 micrograms/ml. Strain CHI thrived well at pH 5.0 and 26.0 degrees C and was tolerant to 20% NaCl. Styrene was subsequently produced in ground fish meat containing cinnamic acid into which strain CHI had been inoculated. The yeast was found to be an environmental contaminant in food processing plants of the chikuwa manufacturer.