Novel MAP applications for fresh-prepared produce 193 10.3 Testing novel MAP applications Two industrially funded research Clubs were set up at CCfRA to investigate in detail the interesting effects of novel MAP on fresh prepared produce. A High O2 MAP Club ran from April, 1995 to September, 1997 and as a follow-up, a Novel Gases MAP Club ran from January, 1998 to December, 1999. These Clubs were supported by a total of nine prepared produce suppliers, five gas companies, four ckaging film suppliers, three retailers, two suppliers of non-sulphite dips, two manufacturers of MAP machinery and two gas instrument companies In addition, further investigations were carried out during a three-year EU FAIR funded project, which started in September 1996. The overall objective of this project was to develop safe commercial applications of novel MAP for extending the quality shelf-life of a wide range of fresh prepared produce items Other aims included investigations of the effects of novel MAP on non-sulphite dipped prepared produce, labile nutritional components, and microbial and biochemical spoilage mechanisms. The major focus of this research was on high O2 MAP, followed by Ar MAP, and to a minor extent, N2O MAP In summary, the following major results and achievements were made during the course of CCfra's Club and eu-funded novel map research High O2 compatible MAP machines were used safely and successfully during the course of the projects experimental trial work. A non-confidential guidelines document on the safe use of high O, MAP was published(BCGa 1998) Enzymic discolorations of prepared non-sulphite dipped potatoes and apples were generally more effectively inhibited by anaerobic (<2% O2) MAP ombinations of N2, Ar and COz, compared with high O2 MAP. However, high O2 MAP was found to have certain odour and textural benefits for prepared potatoes and apples. Also, high O2 Ma packed non-sulphite dipped prepared potatoes and bananas were found to have longer achievable shelf- lives, in comparison with equivalent low O2(8%)MA packed control For most prepared produce items, under defined storage and packaging conditions, high O2 MAP was found to have beneficial effects on sensory uality in comparison with industry-standard air packing and low O2 MAP High O2 MAP was found to be effective for extending the achievable shelf- lives of prepared iceberg lettuce, sliced mushrooms, broccoli florets, Cos lettuce, baby-leaf spinach, raddichio lettuce, lollo rossa lettuce, flat-leaf parsley, cubed swede, coriander, raspberries, strawberries, grapes and Ar-containing and N2O-containing MAP treatments were found to have negligible, variable or only minor beneficial effects on the sensory quality of several prepared produce items, in comparison with equivalent N2-containing MAP treatments High O2 MAs were found to inhibit the growth of several generic groups of bacteria, yeasts and moulds, as well as a range of specific food pathogenic
10.3 Testing novel MAP applications Two industrially funded research Clubs were set up at CCFRA to investigate in detail the interesting effects of novel MAP on fresh prepared produce. A High O2 MAP Club ran from April, 1995 to September, 1997 and as a follow-up, a Novel Gases MAP Club ran from January, 1998 to December, 1999. These Clubs were supported by a total of nine prepared produce suppliers, five gas companies, four packaging film suppliers, three retailers, two suppliers of non-sulphite dips, two manufacturers of MAP machinery and two gas instrument companies. In addition, further investigations were carried out during a three-year EU FAIR funded project, which started in September 1996. The overall objective of this project was to develop safe commercial applications of novel MAP for extending the quality shelf-life of a wide range of fresh prepared produce items. Other aims included investigations of the effects of novel MAP on non-sulphite dipped prepared produce, labile nutritional components, and microbial and biochemical spoilage mechanisms. The major focus of this research was on high O2 MAP, followed by Ar MAP, and to a minor extent, N2O MAP. In summary, the following major results and achievements were made during the course of CCFRA’s Club and EU-funded novel MAP research: • High O2 compatible MAP machines were used safely and successfully during the course of the project’s experimental trial work. A non-confidential guidelines document on the safe use of high O2 MAP was published (BCGA, 1998). • Enzymic discolorations of prepared non-sulphite dipped potatoes and apples were generally more effectively inhibited by anaerobic (<2% O2) MAP combinations of N2, Ar and CO2, compared with high O2 MAP. However, high O2 MAP was found to have certain odour and textural benefits for prepared potatoes and apples. Also, high O2 MA packed non-sulphite dipped prepared potatoes and bananas were found to have longer achievable shelflives, in comparison with equivalent low O2 (8%) MA packed control samples. • For most prepared produce items, under defined storage and packaging conditions, high O2 MAP was found to have beneficial effects on sensory quality in comparison with industry-standard air packing and low O2 MAP. High O2 MAP was found to be effective for extending the achievable shelflives of prepared iceberg lettuce, sliced mushrooms, broccoli florets, Cos lettuce, baby-leaf spinach, raddichio lettuce, lollo rossa lettuce, flat-leaf parsley, cubed swede, coriander, raspberries, strawberries, grapes and oranges (Tables 10.1 and 10.2). • Ar-containing and N2O-containing MAP treatments were found to have negligible, variable or only minor beneficial effects on the sensory quality of several prepared produce items, in comparison with equivalent N2-containing MAP treatments. • High O2 MAs were found to inhibit the growth of several generic groups of bacteria, yeasts and moulds, as well as a range of specific food pathogenic Novel MAP applications for fresh-prepared produce 193
194 Novel food packaging techniques Table 10.1 Overall achievable shelf-life obtained from fresh prepared iceberg lettuce LAP Storage days at 8 C to drop to Shelf-life limiting Overall treatments uality attribute(s) achievable shelf-life Appearance Odour Texture 095 Appearance/texture 4 days CO285%N27 Appearance/odour 7 days 80%Oy 20%N2 11 11 Appearance/odour/ 11 days and spoilage microorganisms, namely Aeromonas hydrophila, salmonella enteritidis, Pseudomonas putida, Rhizopus stolonifer, Botrytis cinerea Penicillium roqueforti, Penicillium digitatum and Aspergillus niger (e.g Figs 10.3 and 10. 4). High O MAs alone were not found to inhibit or stimulate the growth of Pseudomonas fragi, Bacillus cereus, Lactobacillus sake, Yersinia enterocolitica and Listeria monocytogenes, but the addition of 10-30%CO2 inhibited the growth of all these bacteria. Ar-containing and N2O-containing MAs were found to have negligible antimicrobial effects on Table 10.2 Overall achievable shelf-life obtained from several fresh prepared produce Prepared produce items Overall achievable shelf-life(days)at &C Industry standard air/low High O2 MAP O, MAP 4-11 ananas 4 Cos lettuce Strawberries Baby leaf spinach Lolla rossa lettuce Radicchio lettuce Flat leaf parsley Coriander Cubed swede 3 9 Little gem lettuce 4-8 Dipped potate 3-6 Baton carrots Sliced mushrooms
and spoilage microorganisms, namely Aeromonas hydrophila, Salmonella enteritidis, Pseudomonas putida, Rhizopus stolonifer, Botrytis cinerea, Penicillium roqueforti, Penicillium digitatum and Aspergillus niger (e.g. Figs 10.3 and 10.4). High O2 MAs alone were not found to inhibit or stimulate the growth of Pseudomonas fragi, Bacillus cereus, Lactobacillus sake, Yersinia enterocolitica and Listeria monocytogenes, but the addition of 10–30% CO2 inhibited the growth of all these bacteria. Ar-containing and N2O-containing MAs were found to have negligible antimicrobial effects on Table 10.1 Overall achievable shelf-life obtained from fresh prepared iceberg lettuce trial MAP Storage days at 8ºC to drop to Shelf-life limiting Overall treatments quality grade C quality attribute(s) achievable shelf-life Appearance Odour Texture 5% O2/95% N2 4 7 4 Appearance/texture 4 days 5% O2/10% CO2/85% N2 7 7 8 Appearance/odour 7 days 80% O2/ 20% N2 11 11 11 Appearance/odour/ 11 days texture Table 10.2 Overall achievable shelf-life obtained from several fresh prepared produce trials Prepared produce items Overall achievable shelf-life (days) at 8ºC Industry standard air/low High O2 MAP O2 MAP Iceberg lettuce 2–4 4–11 Dipped sliced bananas 2 4 Broccoli florets 2 9 Cos lettuce 3 7 Strawberries 1–2 4 Baby leaf spinach 7 9 Lolla Rossa lettuce 4 7 Radicchio lettuce 3 4 Flat leaf parsley 4 9 Coriander 4 7 Cubed swede 3 10 Raspberries 5–7 9 Little Gem lettuce 4–8 6–8 Dipped potatoes 2–3 3–6 Baton carrots 3–4 4 Sliced mushrooms 2 6 194 Novel food packaging techniques