Acrylamide concentrations in potato crisps in Europe from 2002 to 2011

Figures & data

Table 1. Number of observations (n), mean (ng g^–1), standard error of mean (SE), variance, minimum, median (Q50), 95% quantile (Q95) and maximum values for acrylamide in samples of potato crisps from 2002 to 2011.

Year	n	Mean	SE	Variance	Minimum	Q50	Q95	Maximum
2002	42	763	91.1	348,149	70	493	2080	2500
2003	136	573	27.3	101,440	160	475	1118	2080
2004	321	624	26.6	227,186	130	490	1580	4450
2005	230	621	21.3	103,875	100	565	1210	1780
2006	1151	577	11.9	163,776	22	460	1350	2830
2007	3206	570	7.0	157,220	30	476	1270	5900
2008	5692	472	5.1	145,005	30	367	1170	4300
2009	6493	500	5.8	215,229	40	350	1400	6000
2010	10,971	435	4.1	182,087	22	330	1020	12,000
2011	12,213	358	2.5	74,727	17	280	870	3090

Figure 1. Distribution (histogram) of the log_e(acrylamide) values (ng g⁻¹) in samples of potato crisps.

Table 2. Mean acrylamide (ng g^–1) on the natural log (to base e) scale in samples of potato crisps for each year from 2002 to 2011, with number of observations (n).

Year	Mean (on loge scale)	n	Year	Mean (on loge scale)	n
2002	6.351	42	2007	6.148	3206
2003	6.217	136	2008	5.908	5692
2004	6.250	321	2009	5.899	6493
2005	6.286	230	2010	5.833	10,971
2006	6.158	1151	2011	5.654	12,213

Table 3. Least significant difference (LSD) values on 40,445 degrees of freedom at the 5% (p < 0.05) level of significance, from analysis of variance of acrylamide in samples of potato crisps from 2002 to 2011.

2003	0.2367
2004	0.2200	0.1372
2005	0.2250	0.1451	0.1158
2006	0.2107	0.1216	0.0846	0.0969
2007	0.2083	0.1174	0.0785	0.0915	0.0461
2008	0.2077	0.1164	0.0769	0.0902	0.0433	0.0296
2009	0.2076	0.1162	0.0767	0.0900	0.0429	0.0289	0.0243
2010	0.2073	0.1157	0.0759	0.0893	0.0415	0.0269	0.0219	0.0210
2011	0.2073	0.1156	0.0758	0.0892	0.0413	0.0266	0.0215	0.0206	0.0176
	2002	2003	2004	2005	2006	2007	2008	2009	2010

Note: The value for a particular comparison of the means in Table 2 is given by reading along the appropriate row and up the appropriate column.

Figure 2. Overall mean acrylamide levels (ng g⁻¹) in samples of potato crisps shown over years from 2002 to 2011, with standard errors and with trend in 95% (Q95) quantiles (red).

Figure 3. Seasonality in acrylamide levels in samples of potato crisps from 2002 to 2011. (a) Mean acrylamide levels over time (2002–2011) with standard errors, plotted monthly. (b) Mean acrylamide levels per month over all years with standard errors and with trend in 95% (Q95) quantiles (red).

Table 4. Number of observations (n), mean (ng g^–1), standard error of mean (SE), median (Q50) and 95% quantile (Q95) values for acrylamide in samples of potato crisps for each month using data from 2002 to 2011.

Month	n	Mean	SE	Q50	Q95
January	2561	554	8.0	453	1285
February	2543	540	7.8	422	1300
March	3689	546	7.4	434	1310
April	3258	519	7.2	420	1200
May	3615	551	9.2	419	1375
June	3377	462	6.8	354	1200
July	3191	302	5.2	220	763
August	3279	318	5.1	233	800
September	3779	314	4.8	230	820
October	3339	395	5.2	316	970
November	4088	434	5.4	340	1060
December	3736	450	5.4	360	1040

Figure 4. Percentage of samples of potato crisps in each year from 2002 to 2011 containing >1000 or 2000 ng g⁻¹ acrylamide.

Table 5. Number and percentage of potato crisp samples containing more than 1000 or 2000 ng g^–1 acrylamide for each year from 2002 to 2011.

Year	Total number	Number > 1000 ng g^–1	Percentage > 1000 ng g^–1	Number > 2000 ng g^–1	Percentage > 2000 ng g^–1
2002	42	10	23.8	2	4.8
2003	136	11	8.1	1	0.7
2004	321	41	12.8	4	1.2
2005	230	31	13.5	0	0.0
2006	1151	130	11.3	15	1.3
2007	3206	320	10.0	28	0.9
2008	5692	429	7.5	44	0.8
2009	6493	706	10.9	97	1.5
2010	10,971	566	5.2	105	1.0
2011	12,213	386	3.2	27	0.2